Kawasaki KX125 is a high-performance motorcycle designed for motocross racing. It features a powerful 125cc two-stroke engine that delivers explosive acceleration and lightning-fast response. The KX125's lightweight chassis and nimble handling make it easy to maneuver through tight corners and over challenging terrain. With its advanced suspension system and powerful brakes, the KX125 provides exceptional stability and control, allowing riders to push their limits and experience the thrill of motocross racing.
Advertisement
Advertisement
KX125
KX250
This quick reference guide will assist you in locating a desired topic or procedure.
•Bend the pages back to match the black tab of the desired chapter number with the black tab on the edge at each table of contents page.
•Refer to the sectional table of contents for the exact pages to locate the specific topic required.
Engine Bottom End/Transmission 8 j
KX125
KX250
All rights reserved. No parts of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic mechanical photocopying, recording or otherwise, without the prior written permission of Quality Assurance Division/Consumer Products & Machinery
Company/Kawasaki Heavy Industries, Ltd., Japan.
No liability can be accepted for any inaccuracies or omissions in this publication, although every possible care has been taken to make it as complete and accurate as possible.
The right is reserved to make changes at any time without prior notice and without incurring an obligation to make such changes to products manufactured previously. See your Motorcycle dealer for the latest information on product improvements incorporated after this publication.
All information contained in this publication is based on the latest product information available at the time of publication. Illustrations and photographs in this publication are intended for reference use only and may not depict actual model component parts.
© 2002 Kawasaki Heavy Industries, Ltd., 7th Edition (1) : Mar. 22, 2007 (K)
ft g h
L
°C
DC
F
°F
A
ABDC
AC
ATDC
BBDC
BDC
BTDC ampere(s) after bottom dead center alternating current after top dead center before bottom dead center bottom dead center before top dead center degree(s) Celsius direct current farad(s) degree(s) Fahrenheit foot, feet gram(s) hour(s) liter(s)
LIST OF ABBREVIATIONS
TIR
V
W
Ω lb m min
N
Pa
PS psi r rpm
TDC pound(s) meter(s) minute(s) newton(s) pascal(s) horsepower pound(s) per square inch revolution revolution(s) perminute top dead center total indicator reading volt(s) watt(s) ohm(s)
This manual is designed primarily for use by trained mechanics in a properly equipped shop.
However, it contains enough detail and basic information to make it useful to the owner who desires to perform his own basic maintenance and repair work. A basic knowledge of mechanics, the proper use of tools, and workshop procedures must be understood in order to carry out maintenance and repair satisfactorily. Whenever the owner has insufficient experience or doubts as to his ability to do the work, all adjustments, maintenance, and repair should be carried out only by qualified mechanics.
In order to perform the work efficiently and to avoid costly mistakes, read the text, thoroughly familiarize yourself with the procedures before starting work, and then do the work carefully in a clean area. Whenever special tools or equipment are specified, do not use makeshift tools or equipment. Precision measurements can only be made if the proper instruments are used, and the use of substitute tools may adversely affect safe operation.
To get the longest life out of your motorcycle:
•
Follow the Periodic Maintenance Chart in the
Service Manual.
•
Be alert for problems and non-scheduled maintenance.
•
Use proper tools and genuine Kawasaki motorcycle parts. Special tools, gauges, and testers that are necessary when servicing
Kawasaki Motorcycles are introduced by the
Service Manual. Genuine parts provided as spare parts are listed in the Parts Catalog.
•
Follow the procedures in this manual carefully. Don’t take shortcuts.
•
Remember to keep complete records of maintenance and repair with dates and any new parts installed.
In this manual, the product is divided into its major systems and these systems make up the manual’s chapters. The Quick Reference
Guide shows you all of the product’s system and assists in locating their chapters. Each chapter in turn has its own comprehensive Table of Contents.
For example, if you want ignition coil information, use the Quick Reference Guide to locate the Electrical System chapter. Then, use the
Table of Contents on the first page of the chapter to find the Ignition Coil section.
Whenever you see these WARNING and
CAUTION symbols, heed their instructions!
Always follow safe operating and maintenance practices.
WARNING
This warning symbol identifies special instructions or procedures which, if not correctly followed, could result in personal injury, or loss of life.
CAUTION
This caution symbol identifies special instructions or procedures which, if not strictly observed, could result in damage to or destruction of equipment.
This manual contains four more symbols (in addition to WARNING and CAUTION) which will help you distinguish different types of information.
NOTE
○
•
Indicates a procedural step or work to be done.
○
Indicates a procedural sub-step or how to do the work of the procedural step it follows. It also precedes the text of a NOTE.
Indicates a conditional step or what action to take based on the results of the test or inspection in the procedural step or sub-step it follows.
In most chapters an exploded view illustration of the system components follows the Table of
Contents. In these illustrations you will find the instructions indicating which parts require specified tightening torque, oil, grease or a locking agent during assembly.
Table of Contents
1
Before Servicing
Before starting to perform an inspection service or carry out a disassembly and reassembly operation on a motorcycle, read the precautions given below. To facilitate actual operations, notes, illustrations, photographs, cautions, and detailed descriptions have been included in each chapter wherever necessary. This section explains the items that require particular attention during the removal and reinstallation or disassembly and reassembly of general parts.
Especially note the following:
(1) Dirt
Before removal and disassembly, clean the motorcycle. Any dirt entering the engine will shorten the life of the motorcycle. For the same reason, before installing a new part, clean off any dust or metal filings.
(2) Battery Ground
Disconnect the ground (–) cable from the battery before performing any disassembly operations on the motorcycle. This prevents the engine from accidentally turning over while work is being carried out, sparks from being generated while disconnecting the leads from electrical parts, as well as damage to the electrical parts themselves. For reinstallation, first connect the positive cable to the positive (+) terminal of the battery
(3) Installation, Assembly
Generally, installation or assembly is the reverse of removal or disassembly. However, if installation or assembly sequence is given in this Service Manual, follow it. Note parts locations and cable, wire, and hose routing during removal or disassembly so they can be installed or assembled in the same way. It is preferable to mark and record the locations and routing whenever possible.
(4) Tightening Sequence
When installing bolts, nuts, or screws for which a tightening sequence is given in this Service
Manual, make sure to follow the sequence. When installing a part with several bolts, nuts, or screws, start them all in their holes and tighten them to a snug fit, thus ensuring that the part has been installed in its proper location. Then, tighten them to the specified torque in the tightening sequence and method indicated. If tightening sequence instructions are not given, tighten them evenly in a cross pattern. Conversely, to remove a part, first loosen all the bolts, nuts, or screws that are retaining the part a 1/4-turn before removing them.
(5) Torque
When torque values are given in this Service Manual, use them. Either too little or too much torque may lead to serious damage. Use a good quality, reliable torque wrench.
(6) Force
Common sense should dictate how much force is necessary in assembly and disassembly. If a part seems especially difficult to remove or install, stop and examine what may be causing the problem. Whenever tapping is necessary, tap lightly using a wooden or plastic-faced mallet. Use an impact driver for screws (particularly for the removing screws held by non-permanent locking agent) in order to avoid damaging the screw heads.
(7) Edges
Watch for sharp edges, as they could cause injury through careless handling, especially during major engine disassembly and assembly. Use a clean piece of thick cloth when lifting the engine or turning it over.
(8) High-Flash Point Solvent
A high-flash point solvent is recommended to reduce fire danger. A commercial solvent commonly available in North America is standard solvent (generic name). Always follow manufacturer and container directions regarding the use of any solvent.
(9) Gasket, O-ring
Replace a gasket or an O-ring with a new part when disassembling. Remove any foreign matter from the mating surface of the gasket or O-ring to ensure a perfectly smooth surface to prevent oil or compression leaks.
(10)Liquid Gasket, Locking Agent
Clean and prepare surfaces where liquid gasket or non-permanent locking agent will be used.
Apply them sparingly. Excessive amount may block engine oil passages and cause serious damage.
Before Servicing
(11)Press
When using a press or driver to install a part such as a wheel bearing, apply a small amount of oil to the area where the two parts come in contact to ensure a smooth fit.
(12)Ball Bearing and Needle Bearing
Do not remove a ball bearing or a needle bearing unless it is absolutely necessary. Replace any ball or needle bearings that were removed with new ones. Install bearings with the manufacturer and size marks facing out, applying pressure evenly with a suitable driver. Apply force only to the end of the race that contacts the press fit portion, and press it evenly over the base component.
(13)Oil Seal and Grease Seal
Replace any oil or grease seals that were removed with new ones, as removal generally damages seals. Oil or grease seals should be pressed into place using a suitable driver, applying a force uniformly to the end of seal until the face of the seal is even with the end of the hole, unless instructed otherwise. When pressing in an oil or grease seal which has manufacturer’s marks, press it in with the marks facing out.
(14)Circlip, Retaining Ring, and Cotter Pin
When installing circlips and retaining rings, take care to compress or expand them only enough to install them and no more. Install the circlip with its chamfered side facing load side as well.
Replace any circlips, retaining rings, and cotter pins that were removed with new ones, as removal weakens and deforms them. If old ones are reused, they could become detached while the motorcycle is driven, leading to a major problem.
(15)Lubrication
Engine wear is generally at its maximum while the engine is warming up and before all the sliding surfaces have an adequate lubricative film. During assembly, make sure to apply oil to any sliding surface or bearing that has been cleaned. Old grease or dirty oil could have lost its lubricative quality and may contain foreign particles that act as abrasives; therefore, make sure to wipe it off and apply fresh grease or oil. Some oils and greases in particular should be used only in certain applications and may be harmful if used in an application for which they are not intended.
(16)Direction of Engine Rotation
To rotate the crankshaft manually, make sure to do so in the direction of positive rotation. Positive rotation is counterclockwise as viewed from the left side of the engine. To carry out proper adjustment, it is furthermore necessary to rotate the engine in the direction of positive rotation as well.
(17)Replacement Parts
When there is a replacement instruction, replace these parts with new ones every time they are removed.
Replacement parts will be damaged or lose their original function once they are removed. Therefore, always replace these parts with new ones every time they are removed. Although the previously mentioned gasket, O-ring, ball bearing, needle bearing, grease seal, oil seal, circlip, and cotter pin have not been so designated in their respective text, they are replacement parts.
(18)Electrical Leads
All the electrical leads are either one-color or two-color. A two-color lead is identified first by the primary color and then the stripe color. For example, a yellow lead with thin red stripes is referred to as a “yellow/red” lead; it would be a “red/yellow” lead if the colors were reversed.
Unless instructed otherwise, electrical leads must be connected to leads of the same color.
Two-Color Electrical
Before Servicing
(19)Inspection
When parts have been disassembled, visually inspect these parts for the following conditions or other damage. If there is any doubt as to the condition of them, replace them with new ones.
Abrasion
Bent
Color change
Crack
Dent
Deterioration
Hardening
Scratch
Seizure
Warp
Wear
(20)Specifications
Specification terms are defined as follows:
“Standards” show dimensions or performances which brand-new parts or systems have.
“Service Limits” indicate the usable limits. If the measurement shows excessive wear or deteriorated performance, replace the damaged parts.
Model Identification
KX125-M1 Left Side View
KX125-M1 Right Side View
Model Identification
KX250-M1 Left Side View
KX250-M1 Right Side View
General Specifications
Items
Dimensions
Overall Length
Overall Width
Overall Height
Wheelbase
Road Clearance
Seat Height
Dry Mass
Curb Mass:
Front
Rear
Fuel Tank Capacity
Engine
Type
KX125-M1
2 155 mm (84.8 in.)
825 mm (32.5 in.)
1 200 mm (47.2 in.)
1 455 mm (57.3 in.)
340 mm (13.4 in.)
930 mm (36.6 in.)
87 kg (192 lb)
45 kg (99 lb)
47 kg (104 lb)
8.2 L (2.2 US gal)
2-stroke, single cylinder, crankcase reed valve
Liquid-cooled
54.0 × 54.5 mm (2.13 × 2.15 in.)
124 cm³(7.6 cu in.)
Cooling System
Bore and Stroke
Displacement
Compression Ratio:
Low Speed
High Speed
Carburetion System
Starting System
Ignition System
Ignition Timing
Spark Plug
Port Timing
Inlet:
Open
Close
Scavenging:
Open
Close
Exhaust:
Open
10.6 : 1
8.1 : 1
Carburetor, MIKUNI TMX38χ
Primary kick
CDI
13° BTDC @9 710 r/min (rpm)
NGK BR9EIX
Full open
–
64.9° BBDC
64.9° ABDC
Close
73.8° BBDC (low speed),
95.4° BBDC (high speed)
73.8° ABDC (low speed),
95.4° ABDC (high speed)
Petrol mix (32 : 1) Lubrication System
(Gasoline : Oil)
Drive Train
Primary Reduction
System:
Type
Reduction Ratio
Gear
3.200 (64/20)
KX125-M2
∼
M3 KX125M6F
∼
2 165 mm (85.2 in.)
840 mm (33.1 in.) 815 mm (32.1 in.)
1 265 mm (49.8 in.)
1 470 mm (57.9 in.)
←
940 mm (37.0 in.)
←
←
←
←
←
←
←
←
←
←
←
←
←
11.1 : 1 (EUR) 10.9 : 1
8.5 : 1 (EUR) 8.3 : 1
←
←
←
13° BTDC @9 710 r/min (rpm)
NGK R6918B-9 NGK BR9ECMVX
←
–
←
←
←
←
Viscosity
Capacity
Frame
Type
Steering Angle
Caster (rake angle)
Trail
Front Tire:
Size
Make/Type
Rear Tire:
Size
Make/Type
Rim Size:
Front
Rear
Front Suspension:
Type
Wheel Travel
Rear Suspension:
Type
Wheel Travel
Brake Type:
Front and Rear
General Specifications
Items
Clutch Type
Transmission:
Type
KX125-M1
Wet, multi disc
6-speed, constant mesh, return shift
Gear Ratios:
1st
2nd
3rd
4th
5th
6th
Final Drive System:
Type
Reduction Ratio
Overall Drive Ratio
Transmission Oil:
Grade
2.384 (31/13)
1.857 (26/14)
1.529 (26/17)
1.294 (22/17)
1.125 (27/24)
1.000 (25/25)
Chain drive
3.923 (51/13)
12.553 @Top gear
API SE, SF or SG
API SH or SJ with JASO MA
SAE 10W-40
0.7 L (0.74 US qt)
Tubular, semi-double cradle
45° to either side
27.5°
100 mm (3.9 in.)
80/100-21 51M
DUNLOP, Tube type
100/90-19 57M
DUNLOP, Tube type
21 × 1.60
19 × 1.85
Telescopic fork (up side down)
300 mm (11.8 in.)
Swingarm (Uni-trak)
310 mm (12.2 in.)
Single disc
KX125-M2
∼
M3 KX125M6F
∼
←
←
←
←
←
←
←
←
←
←
←
←
←
API SH, SJ or
SL with JASOMA
(KX125M7F
∼
)
←
←
42° to either side
27°
113 mm (4.4 in.)
←
←
←
←
←
←
←
←
Swingarm (New Uni-trak)
←
←
General Specifications
Rear
Items
Effective Disc Diameter:
Front
KX125-M1
220 mm (8.7 in.)
200 mm (7.9 in.)
KX125-M2
∼
M3 KX125M6F
225 mm (8.9 in.)
215 mm (8.5 in.)
Specifications are subject to change without notice, and may not apply to every country.
(EUR): Europe Model
∼
General Specifications
Items
Dimensions
Overall Length
Overall Width
Overall Height
Wheelbase
Road Clearance
Seat Height
Dry Mass
Curb Mass:
Front
Rear
Fuel tank Capacity
Engine
Type
KX250-M1
2 175 mm (85.6 in.)
825 mm (32.5 in.)
1 205 mm (47.4 in.)
1 480 mm (58.3 in.)
355 mm (14.0 in.)
945 mm (37.2 in.)
97 kg (214 lb)
50 kg (110 lb)
51 kg (112 lb)
8.2 L (2.2 US gal)
Cooling System
Bore and Stroke
Displacement
Compression Ratio
Low Speed
High Speed
Carburetion System
Starting System
Ignition System
Ignition Timing
Spark Plug
Port Timing:
Inlet:
Open
Close
Scavenging:
2-stroke, single cylinder, piston reed valve
Liquid-cooled
66.4 × 72.0 mm (2.61 × 2.85 in.)
249 cm³ (15.25 cu in.)
10.1 : 1
8.6 : 1
Carburetor, KEIHIN PWK38S
Primary kick
CDI
14° BTDC @7 740 r/min (rpm)
NGK BR8EIX
Full open
–
Open
Close
Exhaust:
Open
57.6° BBDC
57.6° ABDC
78.1° BBDC (low speed),
91.4° BBDC (high speed)
78.1° ABDC (low speed), Close
91.4° ABDC (high speed)
Lubrication System (Gasoline: Oil) Petrol mix (32 : 1)
Drive Train
Primary Reduction System:
Type
Reduction ratio
Clutch Type
Gear
3.000 (63/21)
Wet, multi disc
KX250-M2
←
840 mm (33.1 in.)
1 265 mm (49.8 in.)
←
340 mm (13.4 in.)
←
←
←
←
←
←
←
←
←
10.5 : 1
8.8 : 1
←
←
←
←
←
←
–
59.3° BBDC
59.3° ABDC
78.4° BBDC (low speed),
92.2° BBDC (high speed)
78.4° ABDC (low speed),
92.2° ABDC (high speed)
←
←
←
←
General Specifications
Transmission:
Type
Items
Gear Ratios:
1st
2nd
3rd
4th
5th
Final Drive System
Type
Reduction Ratio
Overall Drive Ratio
Transmission Oil:
Grade
Viscosity
Capacity
Frame
Type
Steering Angle
Caster (rake angle)
Trail
Front Tire:
Size
Make/Type
Rear Tire:
Size
Make/Type
Rim Size:
Front
Rear
Front Suspension:
Type
Wheel Travel
Rear Suspension:
Type
Wheel Travel
Brake Type:
Front and Rear
KX250-M1
5 speed, constant mesh, return shift
1.800 (27/15)
1.437 (23/16)
1.176 (20/17)
1.000 (21/21)
0.869 (20/23)
Chain drive
3.769 (49/13)
9.832 @Top gear
API SE, SF or SG
API SH or SJ with JASO MA
SAE 10W-40
0.85 L (0.90 US qt)
Tubular, semi-double cradle
45° to either side
27°
97 mm (3.8 in.)
80/100-21 51M
BRIDGESTONE, Tube type
(EUR) DUNLOP, Tube type
110/90-19 62M
BRIDGESTONE, Tube type
(EUR) DUNLOP, Tube type
21 × 1.60
19 × 2.15
Telescopic fork (up side down)
300 mm (11.8 in.)
Swingarm (Uni-trak)
310 mm (12.2 in.)
Single disc
KX250-M2
←
←
←
←
←
←
←
←
←
←
←
←
←
←
42° to either side
←
112 mm (4.4 in.)
←
←
←
←
←
←
←
←
←
←
Swingarm (New Uni-trak)
←
←
General Specifications
Front
Rear
Items
Effective Disc Diameter:
KX250-M1 KX250-M2
220 mm (8.7 in.)
200 mm (7.9 in.)
225 mm (8.9 in.)
215 mm (8.5 in.)
Specifications are subject to change without notice, and may not apply to every country.
(EUR): Europe Model
Technical Information
Ratchet-Type Shift Mechanism (KX250M, KX125M)
○
The shift mechanism of the KX250M (5-speed) is shown in the following figure.
○
This mechanism is stronger and simpler than the usual slide type and enables light and positive shifting. When the shift pedal [D] is applied, its turning force is transmitted almost directly to the shift drum [E].
○
The mechanism has shorter length between the shift drum and the drive shaft, compared with the previous model (for example, from 67 mm to 43.2 mm for KX125).
○
The shift force is transmitted as follows:
Shift Pedal → Shift Shaft [F] → Shift Mechanism Arm [G] → Ratchet [H] → Pawls [I], [M] in Ratchet
→ Shift Drum Cam [J] → Shift Forks → Gears
A. Top View
B. Front
C. Ratchet Plate
D. Shift Pedal
E. Shift Drum
F. Top View
G. Shift Mechanism Arm
H. Ratchet
I. Upper Pawls
J. Shift Drum Cam
K. Gear Set Lever
L. Return Spring Pin
M. Lower Pawl
N. Neutral Detent
O. Return Spring
Technical Information
○
This mechanism operates as follows:
1. Suppose the 1st gear position is set as shown.
Neutral Detent [N]
2. Shift Up (for example: shift from 1st to 2nd)
(→) : transmitting of shift force
The shift pedal is lifted. → The arm [G] turns counterclockwise until it stops at pin [L]. → ratchet [H] → lower pawl [M] → shift drum cam [J] → shift drum → The gear is shifted in 2nd position.
3. Ratchet Returns.
The arm [G] returns by force of spring [O]. → The ratchet
[H] disengages to be free by itself. → The set lever [K] holds the shift drum cam [J]. → The ratchet [H] returns
(turns clockwise).
4. The 2nd Gear Position settles.
The upper and lower pawls [I], [M] catch the next teeth inside the shift drum cam [J] → The ratchet [H] settles in position. → The 2nd gear position settles.
5. Shift Down (for example: shift from 2nd to 1st)
The shift pedal is depressed. → The arm [G] turns clockwise until it stops at the pin [L]. → ratchet [H] → upper pawl [I] → shift drum cam [J] → shift drum → The gear is shifted into 1st position. → (continues to operate in the same way as Shift Up)
Technical Information
Chrome Composite Plating Cylinder (KX250M, KX125M)
○
This new cylinder bore [A] has Kawasaki’s composite cylinder plating, which is used for the first time on two stroke engines. The composite plating includes a nickel-phosphorous alloy, inorganic materials like ceramic, silicone carbide and some organic materials.
○
The treatment improves heat transfer of the cylinder for consistent power output, allows closer piston-to-cylinder clearances for more horsepower.
○
The treatment is porous, so it holds lubrication well, and hard, so it resists abrasion and seizure.
○
This plating gets on well even the chamfered edge of the cylinder top or port.
○
This improves the surface of the chamber at the top of the cylinder, preventing hot spots, resultant pre-ignition and other abnormal combustion in the chamber.
Previous Cylinder [A]
New Cylinder [B]
Exhaust Port [C]
Cylinder Top [D]
○
This enables the top end of the exhaust port from round to straight in order to make gas flow smooth and improve mid-high performance and extending piston ring life.
Previous Cylinder [A]
New Cylinder [B]
Exhaust Port [C]
Technical Information
KIPS (Kawasaki Integrated Power Valve System, KX250M, KX125M)
○
KIPS varies the exhaust port height to broaden the useful rpm range for low end and mid-range without sacrificing the top end power (see ’95 KDX200H Service Manual (Part No. 99924-1181-01) for basic information about KIPS).
○
KIPS is 2-stage-3-way type: the main exhaust port is opened earlier than the sub-exhaust ports
(2-stage) and they are opened differently in low, middle and high rpm (3-way).
(In low rpm) resonator: open to fully, sub-exhaust ports and main exhaust port: close
(In middle rpm) resonator: close, main exhaust port: open to fully, sub-exhaust ports open to halfway
(In high rpm) resonator: close, main exhaust port and sub-exhaust ports open fully.
○
The KIPS valve is now made of aluminum instead of steel to save weight.
○
The KIPS main valve holder shape is modified to match the straightened exhaust port, and timing for the main and sub-valves is changed to deliver more power in the low to mid-range.
○
The main valve end is changed from thick end to thin end, reducing exhaust pressure on the valve and making valve operation smooth.
(KX250M)
A. Previous KIPS
B. New KIPS
Technical Information
(KX125M)
A. Previous KIPS
B. New Model
C. Full Opened Position
D. Low Speed Position
E. Straightened Exhaust Passage
○
The KIPS governor is modified so that the exhaust valves operate over a wider rpm range to improve low and mid
-range power and smooth the power delivery.
○
The KX250’s governor inside is changed from straight to concave in order to move the balls smoothly.
Previous Governor [A]
New Governor [B]
Carburetor (KX250M)
○
The 38.7 mm (1.524 in.) Keihin PWK 38S carburetor helps boost mid-range and top-end power.
Technical Information
○
The crescent shaped slide [A] enables the needle to sit closer to the intake ports for quicker throttle response.
○
Large bores in the front and back of the carburetor and a smoother shape (38 to 40 mm-tapered bore [B]) boost mixture flow for more mid-range and top-end power.
○
The semi air bleed needle jet [C] improves throttle response in the very low and low range.
Front [D]
○
The air baffle forms vacuum, the stop narrows the outlet and speeds up outflow from the needle jet, improving atomization.
←—: Fuel Droplets
← - -: Fuel Mist
A. Previous Carburetor
B. New Carburetor
C. Jet Needle
D. Air Baffle
E. Needle Jet
F. Stop
G. Engine Inlet
H. Main Air
○
The new main air inlet tends to take in static pressure and to exclude dynamic pressure and vortexes, making the main air flow stable.
Technical Information
A. Previous Carburetor
B. New Carburetor
C. Jet Needle
D. Air Baffle
E. Main Air
F. Needle Jet
G. Engine Inlet
Carburetor (KX125M)
○
The 38 mm (1.496 in.) Mikuni TMX 38-27 carburetor helps boost mid-range and top-end power.
○
The arched slide [A] improves throttle response in the very low and low ranges.
○
Large bores in the front and back of the carburetor and a smoother shape (38 to 40 mm-tapered bore [B]) boost mixture flow for more mid-range and top-end power.
○
The semi air bleed needle jet [C] improves throttle response in the low range and provides proper mixture from the low to top range.
Front [D]
Technical Information
○
In low range, fuel drops in the fuel/air mixture is larger and tends to stick to the carburetor wall.
The arched slide deflects fuel/air mixture flow from the wall to the middle of the carburetor for better atomization and better throttle response.
A. Previous Carburetor
B. New Carburetor
C. Flat Slide (piston valve)
D. Arched Shape Slide (piston valve)
E. Engine Intake
○
The semi air bleed hole is positioned at the side of the needle jet, where fuel mixes with air well (due to enough fuel and faster air flow than in main bore), resulting in better atomizing. The air screen suppresses dynamic pressure around the main air inlet.
A. Previous Carburetor
B. New Carburetor
C. Jet Needle
D. Air Baffle
E. Main Air
F. Needle Jet
G. Engine Intake
H. Semi Air Bleed Hole
I. Air Screen
Unit Conversion Table
Prefixes for Units:
Prefix mega kilo centi milli micro
Symbol
M k c m
µ
Power
× 1 000 000
× 1 000
× 0.01
× 0.001
× 0.000001
Units of Mass:
kg g
×
×
2.205
=
0.03527
=
Units of Volume:
L × 0.2642
=
L × 0.2200
=
L
L
L
L mL mL mL
×
×
×
×
×
×
×
1.057
=
0.8799
=
2.113
1.816
=
=
0.03381
=
0.02816
=
0.06102
=
Units of Force:
N × 0.1020
=
N kgf kgf
×
×
×
0.2248
=
9.807
=
2.205
=
Units of Temperature:
lb oz kgf lb
N lb gal (US) gal (imp) qt (US) qt (imp) pint (US) pint (imp) oz (US) oz (imp) cu in
Units of Length:
km m mm
×
×
×
0.6214
=
3.281
=
0.03937 =
Units of Torque:
N·m × 0.1020
=
N·m × 0.7376
=
N·m kgf·m kgf·m kgf·m
×
×
×
×
8.851
9.807
7.233
86.80
=
=
=
=
Units of Pressure:
kPa × 0.01020 = kPa × 0.1450
= kPa × kgf/cm² × kgf/cm² × cm Hg ×
0.7501
=
98.07
=
14.22
1.333
=
=
Units of Speed:
km/h
× 0.6214
=
Units of Power:
kW kW
PS
PS
×
×
×
×
1.360
1.341
0.7355
=
0.9863
=
=
= mile ft in
PS
HP kW
HP kgf·m ft·lb in·lb
N·m ft·lb in·lb mph kgf/cm² psi cm Hg kPa psi kPa
Table of Contents
2
Periodic Maintenance Chart
The maintenance must be done in accordance with this chart to keep the motorcycle in good running condition.
FREQUENCY
OPERATION
Spark plug - clean and inspect †
Clutch - inspect
E Clutch plates - inspect †
Throttle cable - inspect
Air cleaner element - clean and inspect
N Air cleaner element - replace
Carburetor - inspect
Transmission oil - change
G Piston and piston ring - clean and inspect†
Cylinder head, cylinder - inspect
Connecting rod- inspect †
Exhaust valve - clean and inspect
Exhaust system - inspect
N Muffler - clean and inspect †
Muffler baffle - change
Kick pedal and shift pedal - clean
E Sprockets - inspect †
Coolant - inspect †
Water hoses and connections - inspect †
Brake adjustment - inspect †
C Brake pad wear - inspect †
Brake fluid level - inspect †
H Brake fluid - change
A
Brake master cylinder cup and dust cover replace
Brake caliper fluid seal and dust seal replace
S Brake hoses and pipe - replace
Brake hoses, connections - inspect †
S Spoke tightness and rim runout - inspect †
After each race or
Every
3 races or 7.5
Every
5 races or 12.5
Every
10 races
•
•
•
•
•
2.5 hr
• hr hr
•
•
•
•
R
•
R
If damaged
•
•
•
•
R
•
•
•
•
•
•
Every 2 years or 25 hr
R
•
•
Every 2 years
Every 2 years
Every 4 years
As required
See
Page
2-47
2-25
2-26
2-14
2-15
2-15
2-15
2-27
2-20
2-19
2-23
2-24
2-24
2-24
2-25
–
2-34
R 2-17
2-19
2-34
2-37
2-35
2-36
2-37
2-37
2-38
2-38
2-30
Wheel bearing - inspect †
•
2-30
I Drive chain - inspect
Drive chain - lubricate
•
•
2-31
2-33
S Drive chain wear - inspect †
Chain slipper and guide - replace
Rear sprocket warp (runout) - inspect †
•
If damaged
•
2-32
2-43
2-34
Front fork - inspect and clean
•
2-39
Periodic Maintenance Chart
OPERATION
Front fork oil - change
FREQUENCY After each race or
2.5 hr
Every
3 races or 7.5
hr
Every
5 races or 12.5
hr
Every
10 races or 25 hr
As required
See
Page
1st time after 2 races, then every 5 races 2-40
I
Rear shock absorber oil - change
C Fuel Tank and Tap - clean
H Fuel hose - replace
A Fuel hose, connections - inspect †
S Steering - inspect †
S Steering stem bearing - lubricate
Swingarm and Uni-Trak linkage pivots lubricate
S Swingarm and Uni-Trak linkage - inspect †
Wheel/tire (air pressure, excessive wear or damage) - inspect
•
Frame - clean and inspect
Nuts, bolts, and fasteners tightness- inspect †
•
•
General lubrication - perform
•
†: Replace, add, adjust, clean or torque if necessary.
1st time after 2 races, then every 5 races 2-42
•
2-16
Every 4 years 2-14
•
•
2-14
2-43
•
•
•
2-46
2-42
2-42
2-28
2-46
2-49
2-48
R: Replace
Torque and Locking Agent
Tighten all bolts and nuts to the proper torque using an accurate torque wrench. If insufficiently tightened, a bolt or nut may become damaged, strip an internal thread, or break and then fall out. The following table lists the tightening toque for the major bolts and nuts, and the parts requiring use of a non-permanent locking agent or liquid gasket.
When checking the tightening toque of the bolts and nuts, first loosen the bolt or nut by half a turn and then tighten to specified torque.
Letters used in the “Remarks” column mean:
L : Apply a non-permanent locking agent to the threads.
LG : Apply liquid gasket to the threads.
S : Tighten the fasteners following the specified sequence.
Fastener
Torque
N·m kgf·m ft·lb
Remarks
Fuel System
Carburetor Holder Mounting Bolts
Carburetor Holding Clamp Screw
Reed Valve Screws
Carburetor Top Cover Screws (KX125)
Carburetor Top Cover Allen Bolts (KX250)
Throttle Sensor Bolt (KX250)
Rear Frame Mounting Bolts
Air Cleaner Duct Clamp Screw
Fuel Tap Plate Mounting Screws
Air Cleaner Duct Nuts
Air Cleaner Housing Bolts
Cooling System
Water Pump Cover Bolts
Water Pump Impeller Bolt
Water Hose Clamp Screws
Coolant Drain Bolt (Water Pump Cover)
Coolant Drain Bolt (Cylinder) (KX250)
Water Hose Elbow Fitting Bolts (Cylinder) (KX250)
Water Pump Cover Fitting Bolts (KX250)
Radiator Shroud Bolts
Radiator Mounting Bolts
Radiator Screen Bolts
Radiator Bracket Bolts
Engine Top End
Main Valve Cover Bolts
Cylinder Head Nuts
Spark Plug
Engine Mounting Bracket Nuts:
Engine Side 10 mm (KX125/250-M1)
Engine Side 10 mm (KX125/250-M2
∼
)
Frame Side 8 m
8.8
1.5
1.0
3.0
3.9
2.0
34
1.5
0.8
3.0
8.8
8.8
6.9
1.5
8.8
8.8
8.8
5.9
8.8
8.8
8.8
8.8
5.9
25
27
44
49
29
0.9
0.15
13 in·lb
0.1
9 in·lb
0.3
0.4
0.2
3.5
0.15
13 in·lb
0.08
7 in·lb
0.3
0.9
0.9
78 in·lb
26 in·lb
35 in·lb
17 in·lb
25
26 in·lb
78 in·lb
0.7
61 in·lb
0.15
13 in·lb
0.9
0.9
0.9
0.6
0.9
0.9
0.9
0.9
0.6
2.5
2.8
4.5
5.0
3.0
78 in·lb
78 in·lb
78 in·lb
78 in·lb
52 in·lb
78 in·lb
78 in·lb
78 in·lb
78 in·lb
52 in·lb
18
20
33
36
22
S
Torque and Locking Agent
Fastener
KIPS Cover Bolts:
KX125-M1
KX125-M2
∼
KX250
Cylinder Nuts:
KX125
KX250
Cylinder Left Cover Bolts (KX250)
Main Lever Mounting Allen Bolt
Governor Shaft Lever Mounting Bolt (KX125)
Exhaust Valve Retaining Bolts (KX125)
Main Shaft Stopper Pin Plug (KX125)
Main Valve Retaining Bolts (KX250)
Operating Rod Retaining Screw (KX250)
Operating Rod Left Side Plug (KX250)
Main Valve Rod Cover Screw (KX250)
Coolant Drain Plug (Cylinder) (KX250)
Inner Pipe Mounting Bolts
Muffler Pipe Mounting Bolts
Muffler Damper Mounting Bolts (KX125/250-M2
∼
)
Expansion Chamber Mounting Bolt (KX125/250-M2
∼
)
Muffler Mounting Bolt
Engine Right Side
Clutch Hub Nut
Clutch Spring Bolts
Clutch Cover Bolts
Governor Shaft Lever Positioning Plug
Oil Filler Cap
Right Engine Cover Bolts
Governer Shaft Lever Mounting Bolt (KX125)
Exhaust Valve Advancer Lever Mounting Allen Bolts
Primary Gear Nut (KX125)
Gear Set Lever Nut
Ratchet Plate Mounting Bolts
Kick Ratchet Guide Bolt
Kick Pedal Bolt:
KX125
KX250
Shift Pedal Bolt
External Shift Mechanism Return Spring Pin (KX250)
Gear Set Lever Pivot Stud
Torque
N·m kgf·m ft·lb
4.9
8.8
2.9
25
34
5.9
3.9
6.9
5.9
0.8
5.9
5.4
22
5.9
8.8
8.8
8.8
8.8
12
8.8
98
8.8
8.8
0.6
1.5
8.8
6.9
3.9
59
8.8
8.8
8.8
12
25
9.8
42
–
0.5
0.9
0.3
2.5
3.5
0.6
0.4
0.7
0.6
0.08
18
25
52 in·lb
35 in·lb
61 in·lb
52 in·lb
7 in·lb
0.6
52 in·lb
0.55
48 in·lb
2.2
0.6
16
52 in·lb
0.9
0.9
0.9
0.9
1.2
0.9
78 in·lb
78 in·lb
78 in·lb
78 in·lb
104in·lb
78 in·lb
10.0
0.9
0.9
0.06
0.15
13 in·lb
0.9
0.7
0.4
6.0
0.9
0.9
0.9
1.2
2.5
1.0
4.3
–
43 in·lb
78 in·lb
26 in·lb
72
78 in·lb
78 in·lb
5 in·lb
78 in·lb
61 in·lb
35 in·lb
43
78 in·lb
78 in·lb
78 in·lb
104 in·lb
18
87 in·lb
31
–
Remarks
L
L
L
L
L
L (Planted
Side)
Torque and Locking Agent
Fastener
Engine Removal/Installation
Engine Mounting Nuts:
KX125/250-M1
KX125/250-M2
∼
Engine Mounting Bracket Nuts:
Engine Side 10 mm (KX125/250-M1)
Engine Side 10 mm (KX125/250-M2
∼
)
Frame Side 8 mm
Swingarm Pivot Shaft Nut
Engine Bottom End/Transmission
Output Shaft Bearing Retaining Screws
Shift Drum Bearing Retaining Screws (KX125-M1)
Shift Drum Bearing Retaining Bolts (KX125-M2
∼
)
Shift Drum Bearing Retaining Bolts (KX250)
Drive Shaft Bearing Retaining Bolts (KX250)
Engine Oil Drain Bolt
Crankcase Bolts
Flywheel Bolt (KX125)
Flywheel Nut (KX250)
Shift Drum Operating Cam Bolt
Cylinder Stud
Wheels/Tires
Front Axle Nut
Front Axle Clamp Bolts
Rear Axle Nut
Spoke Nipple
Final Drive
Rear Axle Nut
Rear Sprocket Nuts
Engine Sprocket Cover Bolts
Brakes
Front Master Cylinder Clamp Bolts
Brake Lever Pivot Bolt
Brake Lever Pivot Bolt Locknut
Brake Hose Banjo Bolts
Brake Pad Bolt
Caliper Bleed Valves (Front, Rear)
Caliper Mounting Bolts (Front)
Rear Master Cylinder Mounting Bolts
Rear Master Cylinder Push Rod Locknut
Torque
N·m kgf·m ft·lb
Remarks
44
49
44
49
29
98
4.5
5.0
4.5
5.0
3.0
10.0
33
36
33
36
22
72
5.4
6.4
8.8
8.8
8.8
20
8.8
22
78
24
–
8.8
5.9
5.9
25
18
7.8
25
9.8
18
2.2
8.0
2.4
–
0.55
48 in·lb
0.65
56 in·lb
0.9
78 in·lb
0.9
0.9
2.0
0.9
78 in·lb
78 in·lb
14.5
78 in·lb
16
58
17
–
L
L
L
L
L
L (Planted
Side)
78
20
108
2.2 or more
8.0
2.0
11.0
0.22 or more
58
14.5
80
19 in·lb or more
108
34
4.9
11.0
3.5
0.5
80
25
43 in·lb
0.9
78 in·lb
0.60
52 in·lb
0.60
52 in·lb
2.5
1.8
0.8
2.5
1.0
1.8
18
13
69 in·lb
18
87 in·lb
13
Torque and Locking Agent
Fastener
Brake Disc Mounting Bolts:
Front
Rear
Caliper Holder Shaft
Rear Brake Pad Bolt Plug
Brake Pedal Mounting Bolt
Suspension
Front Fork Top Plug
Front Fork Clamp Bolts (Upper, Lower)
Piston Rod Nut
Front Axle Clamp Bolts
Front Fork Cylinder Valve Assembly
Swingarm Pivot Shaft Nut
Tie-Rod Mounting Nut (Front, Rear)
Rocker Arm Pivot Nut
Rear Shock Absorber Mounting Nuts:
Upper
Lower
Steering
Steering Stem Head Nut
Steering Stem Locknut
Handlebar Holder Bolts
Front Fork Clamp Bolts (Upper, Lower)
Electrical System
Flywheel Bolt
Flywheel Nut
Stator Plate Mounting Screws
Spark Plug
Magneto Cover Bolts: (KX125/250-M1)
Magneto Cover Bolts: KX125/250-M2
∼
)
C.D.I Unit Mounting Bolts
Ignition Coil Mounting Bolts
39
34
98
4.9
25
20
22
78
4.4
27
4.9
3.9
8.8
8.8
20
54
98
83
83
29
20
28
Torque
N·m kgf·m ft·lb
9.8
23
27
2.5
25
1.0
2.3
2.8
87 in·lb
17
20
0.25
22 in·lb
2.5
18
Remarks
L
L
3.0
2.0
2.9
2.0
5.5
10.0
8.5
8.5
22
14.5
21
14.5
40
72
61
61
L
4.0
3.5
10.0
0.5
2.5
2.0
29
25
72
43 in·lb
18
14.5
2.2
16
8.0
58
0.45
39 in·lb
2.8
0.5
0.4
0.9
0.9
20
43 in·lb
35 in·lb
78 in·lb
78 in·lb
Torque and Locking Agent
Basic Torque for General Fasteners
Threads dia. (mm)
12
14
16
18
20
5
6
8
10
N·m
3.4
∼
4.9
5.9
∼
7.8
14
∼
19
25
∼
34
44
∼
61
73
∼
98
115
∼
155
165
∼
225
225
∼
325
Torque kgf·m
0.35
∼
0.50
0.60
∼
0.80
1.4
∼
1.9
2.6
∼
3.5
4.5
∼
6.2
7.4
∼
10.0
11.5
∼
16.0
17.0
∼
23.0
23
∼
33
ft·lb
30
∼
43 in·lb
52
∼
69 in·lb
10.0
∼
13.5
19.0
∼
25
33
∼
45
54
∼
72
83
∼
115
125
∼
165
165
∼
240
Specifications
Item
Fuel System
Throttle Grip Free Play
Air Cleaner Element Oil
Read Valve Warp
Cooling System
Coolant:
Type (recommended)
Color
Mixed Ratio
Freezing Point
Total Amount:
KX125
KX250
Engine Top End
Cylinder Head Warp
Cylinder, Piston (KX125):
Cylinder Inside Diameter (15 mm
(0.59 in.) below of the cylinder head)
Piston Diameter
2
∼
3 mm (0.08
Permanent type antifreeze
Green
Soft water 50% and coolant 50%
–35°C (–31°F)
– – –
54.010
(2.1264
∼
∼
Standard
∼
0.12 in.)
High quality foam air filter oil
0.97 L (1.02 US qt)
1.20 L (1.27 US qt)
54.025 mm
2.1270 in.)
Service Limit
– – –
– – –
0.5 mm (0.020 in.)
– – –
0.03 mm (0.0012 in.)
54.10 mm (2.130 in.)
Piston/Cylinder Clearance
Piston Ring/Groove clearance
Piston Ring Groove Width
Piston Ring Thickness
Piston Ring End Gap
Piston Pin Diameter
Piston Pin Hole Diameter
Connection Rod Small End Inside
Diameter
Cylinder, Piston (KX250):
Cylinder Inside Diameter (30 mm
(1.18 in.) below of the cylinder
Head)
Piston Diameter
Piston/Cylinder Clearance
Piston Ring/Groove Clearance
Piston Ring Groove Width
Piston Ring Thickness
Piston Ring End Gap
Piston Pin Diameter
53.955
∼
53.970 mm
(2.1242
∼
2.1480 in.)
0.040
∼
0.070 mm (0.0016
∼
0.0028 in.)
0.015
∼
0.050 mm (0.0006
∼
0.0020 in.) 0.15 mm (0.006 in.)
1.01
∼
1.03 mm (0.0398
∼
0.0406 in.) 1.11 mm (0.044 in.)
0.980
∼
0.995 mm (0.0386
∼
0.0392 in.) 0.91 mm (0.036 in.)
0.35
∼
0.55 mm (0.0138
∼
0.0217 in.) 0.85 mm (0.033 in.)
14.995
∼
15.000 mm
(0.5904
∼
0.5906 in.)
14.96 mm (0.589 in.)
15.001
∼
15.011 mm
(0.5906
∼
0.5910 in.)
19.003
∼
19.014 mm
(0.7481
∼
0.7486 in.)
53.81 mm (2.118 in.)
– – –
15.08 mm (0.594 in.)
19.05 mm (0.750 in.)
66.400
∼
66.415 mm
(2.6142
∼
2.6148 in.)
66.46 mm (2.617 in.)
66.336
∼
66.351 mm
(2.6116
∼
2.6122 in.)
0.049
∼
0.079 mm (0.0019
∼
0.0031 in.)
66.19 mm
(2.6059 in.)
– – –
0.025
∼
0.06 mm
(0.00098
∼
0.00236 in.)
0.16 mm (0.006 in.)
1.01
∼
1.03 mm (0.0398
∼
0.0406 in.) 1.11 mm (0.044 in.)
0.970
∼
0.985 mm (0.0382
∼
0.0388 in.) 0.90 mm (0.035 in.)
0.25
∼
0.45 mm (0.0098
∼
0.0177 in.) 0.75 mm (0.030 in.)
17.995
∼
18.000 mm
(0.7085
∼
0.7087 in.)
17.96 mm (0.707 in.)
Specifications
Item
Piston Pin Hole Diameter
Connection Rod Small End Inside
Diameter
Engine Right Side
Clutch Lever Free Play
Friction Plate Thickness
KX125
KX250
Steel Plate Thickness:
KX125
KX250
Friction Plate Warp
Steel Plate Warp
Engine Bottom End/Transmission
Transmission Oil:
Grade
Standard
18.001
∼
18.011 mm
(0.7087
∼
0.7091 in.)
22.003
∼
22.012 mm
(0.8663
∼
0.8666 in.)
2
∼
3 mm (0.08
∼
0.12 in.)
2.72
∼
2.88 mm (0.107
∼
0.113 in.)
2.92
∼
3.08 mm (0.115
∼
0.121 in.)
1.5
∼
1.7 mm (0.059
∼
0.067 in.)
1.46
∼
1.74 mm (0.057
∼
0.069 in.)
0.15 mm (0.006 in.) or Less
0.2 mm (0.008 in.) or Less
API SE, SF or SG
API SH or SJ with JASO MA
API SH, SJ or SL with JASO MA
(KX125M7F
∼
)
SAE 10W-40 Viscosity
Capacity:
KX125
KX250
Wheels/Tires
Rim Runout (with tire installed):
Axial
Radial
Final Drive
Drive Chain Slack
Drive Chain 20 Link Length
0.7 L (0.74 US qt)
0.85 L (0.90 US qt)
TIR 1.0 mm (0.04 in.) or less
TIR 1.0 mm (0.04 in.) or less
52
∼
317.5
62 mm (2.05
∼
∼
2.44 in.)
318.2 mm (12.50
∼
12.53 in.)
Rear Sprocket Warp (Runout) TIR 0.4 mm (0.016 in.) or less
Brakes
Brake Lever Play
Brake Fluid:
Type:
Front
Rear
Brake Pad Lining Thickness:
Front
Rear
Adjustable (to suit rider)
DOT3 or DOT4
DOT4
3.8 mm (0.150 in.)
6.4 mm (0.252 in.)
Service Limit
18.08 mm (0.712 in.)
22.05 mm (0.868 in.)
– – –
2.6 mm (0.102 in.)
2.8 mm (0.110 in.)
1.4 mm (0.055 in.)
1.36 mm (0.054 in.)
0.3 mm (0.012 in.)
0.3 mm (0.012 in.)
– – –
TIR 2 mm (0.08 in.)
TIR 2 mm (0.08 in.)
– – –
323 mm (12.72 in.)
TIR 0.5 mm (0.020
in.)
– – –
– – –
– – –
1 mm (0.04 in.)
1 mm (0.04 in.)
Specifications
Item
Suspension
Fork Oil:
Oil Viscosity
Oil Capacity (par unit):
KX125-M1
KX125-M2
∼
KX250-M1
KX250-M2
∼
Oil Level (fully compressed, spring removed):
KX125-M1
KX125-M2
∼
KX250-M1
KX250-M2
∼
Electrical System
Spark Plug Gap
Standard
KHL15-10 (KAYABA 01) or equivalent
652 ±4 mL (22.04 ±0.14 US oz.)
565 ±4 mL (19.10 ±0.14 US oz.)
664 ±4 mL (22.45 ±0.14 US oz.)
578 ±4 mL (19.54 ±0.14 US oz.)
135 ±2 mm (5.31 ±0.08 in.)
105 ±2 mm (4.13 ±0.08 in.)
125 ±2 mm (4.92 ±0.08 in.)
88 ±2 mm (3.46 ±0.08 in.)
0.7
∼
0.8 mm (0.028
∼
0.031 in.)
Service Limit
– – –
– – –
– – –
– – –
(Adjustable range)
100
∼
145 mm
70
∼
120 mm
(3.94
∼
5.71 in.)
(2.76
∼
4.72 in.)
– – –
Special Tools
Steering Stem Nut Wrench:
57001-1100
Jack:
57001-1238
Fork Piston Rod Puller, M12 × 1.25:
57001-1289
Fork Oil Level Gauge:
57001-1290
Periodic Maintenance Procedures
Fuel System
○
The fuel hoses are designed to be used throughout the motorcycle’s life without any maintenance, however, if the motorcycle is not properly handled, the inside the fuel line can cause fuel to leak [A] or the hose to burst. Remove the fuel tank and check the fuel hose.
Replace the fuel hose if any fraying, cracks [B] or bulges
[C] are noticed.
•
Inspect that the hoses are securely connected and clamps are tightened correctly.
•
When installing, route the hoses according to Cable,
Wire, and Hose Routing section in the Appendix chapter.
•
When installing the fuel hoses, avoid sharp bending, kinking, flattening or twisting, and route the fuel hoses with a minimum of bending so that the fuel flow will not be obstructed.
Replace the hose if it has been sharply bent or kinked.
Throttle Grip Free Play Inspection
•
Inspect throttle grip free play [B] by lightly turning the throttle grip [A] back and forth.
If the free play is improper, adjust the throttle cable.
Throttle Grip Free Play
Standard: 2
∼
3 mm (0.08
∼
0.12 in.)
•
Inspect that the throttle grip moves smoothly from full open to close, and the throttle closes quickly and completely in all steering positions by the return spring.
If the throttle grip does not return properly, check the throttle cable routing, grip free play, and cable damage. Then lubricate the throttle cable.
•
Run the engine at the idle speed, and turn the handlebar all the way to the right and left to ensure that the idle speed does not change.
If the idle speed increase, check the throttle cable free play and the cable routing.
Throttle Grip Free Play Adjustment
•
Loosen the locknut [A] at the upper end of the throttle cable.
•
Turn the adjuster [B] until the proper amount of throttle grip free play is obtained.
•
Tighten the locknut.
Periodic Maintenance Procedures
If the throttle grip free play cannot be adjusted with the adjuster at the upper end of the throttle cable, use the
• cable adjuster [A] at the carburetor.
Free the fuel cut valve connector from the frame.
•
Pull the boot off of the carburetor top. Make the necessary free play adjustment at the lower cable adjuster, tighten the locknut [B], and install the boot.
•
Turn the handlebar from side to side while idling the engine. If idle speed varies, the throttle cable may be poorly routed or it may be damaged.
WARNING
Operation with an improperly adjusted, incorrectly routed, or damaged cable could result in an unsafe riding condition.
•
Idle Speed Inspection
Start the engine and warm it up thoroughly.
•
With the engine idling, turn the handlebar to both sides.
If handlebar movement changes the idle speed, the throttle cable may be improperly adjusted or incorrectly routed, or it may be damaged. Be sure to correct any of these conditions before riding (see Cable, Wire, and Hose Routing in the Appendix chapter).
WARNING
Operation with an improperly adjusted, incorrectly routed, or damaged cable could result in an unsafe riding condition.
•
Check idle speed.
Adjust it as needed.
Idle Speed Adjustment
•
First turn in the air screw [A] until it seats lightly, and back it out the specified number of turns. (see specifications in
• the Fuel System chapter)
Start the engine and warm it up thoroughly.
•
Turn the idle adjusting screw [B] to obtain desired idle speed. If no idle is preferred, turn out the screw until the engine stops.
•
Open and close the throttle a few times to make sure that the idle speed is as desired. Readjust if necessary.
NOTE
○
In dusty areas, the element should be cleaned more frequently than recommended interval.
○
After riding through rain or on muddy roads, the element should be cleaned immediately.
○
Since repeated cleaning opens the pores of the element, replace it with a new one in accordance with the
Periodic Maintenance Chart. Also, if there is a break in the element material or any other damage to the element, replace the element with a new one.
Periodic Maintenance Procedures
WARNING
Clean the element in a well-ventilated area, and take care that there are no sparks or flame anywhere near the working area; this includes any appliance with a pilot light. Because of the danger of highly flammable liquids, do not use gasoline or a low flash-point solvent to clean the element.
•
Remove the air cleaner element, and separate the element [A] from the frame [B].
•
Clean the element in a bath of a high-flash point solvent using a soft bristle brush. Squeeze it dry in a clean towel.
Do not wring the element or blow it dry; the element can be damaged.
•
Inspect all the parts of the element for visible damage.
If any of the parts of the element are damaged, replace them.
•
After cleaning, saturate the element with a high-quality foam-air-filter oil, squeeze out the excess, then wrap it in a clean rag and squeeze it as dry as possible. Be careful
• not to tear the sponge filter.
Assemble the element.
•
Remove the towel from the carburetor.
•
Install the element.
WARNING
Clean the fuel tank in a well-ventilated area, and take care that there is no sparks or flame anywhere near the working area. Because of the danger of highly flammable liquids, do not use gasoline or low flash-point solvent to clean the tank.
•
Remove the fuel tank and drain it.
•
Pour some high-flash point solvent into the fuel tank and shake the tank to remove dirt and fuel deposits.
•
Pour the solvent out of the tank.
•
Remove the fuel tap from the tank by taking out the bolts.
•
Clean the fuel tap filter screen in a high-flash point solvent.
•
Pour high-flash point solvent through the tap in all lever
• positions.
Dry the tank and tap with compressed air.
•
Install the tap in the fuel tank.
•
Install the fuel tank.
Cooling System
Check the coolant level each day before riding the motorcycle, and replenish coolant if the level is low. Change the coolant in accordance with the Periodic Maintenance Chart.
WARNING
To avoid burns, do not remove the radiator cap or try to inspect the coolant level or change the coolant when the engine is still hot. Wait until it cools down.
Periodic Maintenance Procedures
Coolant Level Inspection
NOTE
○
Inspect the level when the engine is cold (room or ambient temperature).
•
Situate the motorcycle so that it is perpendicular to the ground.
•
Remove the radiator cap [A].
NOTE
○
Remove the radiator cap in two steps. First turn the cap counterclockwise to the first stop and wait there for a few seconds. Then push down and turn it further in the same direction and remove the cap.
•
Inspect the coolant level. The coolant level [A] should be at the bottom of the filler neck [B].
If the coolant level is low, add coolant through the filler opening to the bottom of the filler neck. Install the cap.
Recommended coolant:
Permanent type of antifreeze (soft water and ethylene glycol plus corrosion and rust inhibitor chemicals for aluminum engines and radiators)
Water and coolant mixture ratio:
1:1 (water 50 %, Coolant 50 %)
Total amount:
KX125: 0.97 L (1.02 US qt.)
KX250: 1.20 L (1.27 US qt.)
Coolant Deterioration Inspection
•
Visually inspect the coolant.
If whitish cotton-like wafts are observed, aluminum parts in the cooling system are corroded. If the coolant is brown, iron or steel parts are rusting. In either case, flush the cooling system.
If the coolant gives off an abnormal smell, check for a cooling system leak. It may be caused by exhaust gas leaking into the cooling system.
Coolant Draining
The coolant should be changed periodically to ensure long engine life.
WARNING
To avoid burns, do not remove the radiator cap or try to change the coolant when the engine is still hot. Wait until it cools down.
Coolant on tires will make them slippery and can cause an accident and injury. Immediately wipe up or wash away any coolant that spills on the frame, engine or other painted parts. Since coolant is harmful to the human body, do not use for drinking.
Periodic Maintenance Procedures
•
Remove the radiator cap.
NOTE
○
Remove the radiator cap in two steps. First turn the cap counterclockwise to the first stop and wait there for a few seconds. Then push down and turn it further in the same direction and remove the cap.
•
Place a container under the coolant drain plug (KX125)
[A] or plugs (KX250) [B], and drain the coolant from the radiator and engine by removing the drain plug on the water pump cover and the cylinder (KX250). Immediately wipe or wash out any coolant that spills on the frame, engine, or wheel.
•
Inspect the old coolant for visual evidence of corrosion and abnormal smell (see Coolant Deterioration Inspection).
Coolant Filling
CAUTION
Use coolant containing corrosion inhibitors made specifically for aluminum engines and radiators in accordance with the instruction of the manufacture’s. Soft or distilled water must be used with the antifreeze (see below for antifreeze) in the cooling system. If hard water is used in the system, it causes scale accumulation in the water passages, and considerably reduces the efficiency of the cooling system.
Recommended Coolant
Type: Permanent type antifreeze (soft water and ethylene glycol plus corrosion and rust inhibitor chemicals for aluminum engines and radiators)
Color:
Mixed ratio:
Green
Soft water 50%, Coolant 50%
Freezing point: −35°C (−31°F)
Total amount KX125: 0.97 L (1.02 US qt.)
KX250: 1.20 L (1.27 US qt.)
•
Install the drain plug.
○
Replace the gasket with a new one.
•
Tighten:
Torque - Coolant Drain Plug on Water Pump Cover: 8.8 N·m
(0.9 kgf·m, 78 in·lb)
Coolant Drain Plug on Cylinder (KX250): 8.8 N·m
(0.9 kgf·m, 78 ft·lb)
Periodic Maintenance Procedures
•
Fill the radiator up to the bottom of the radiator filler neck
[B] with coolant [A], and install the cap, turning it clockwise about 1/4 turn.
NOTE
○
Pour in the coolant slowly so that it can expel the air from the engine and radiator. The radiator cap must be installed in two steps. First turn the cap clockwise to the first stop. Then push down on it and turn it the rest of the way.
•
Check the cooling system for leaks.
Air Bleeding
Before putting the motorcycle into operation, any air
• trapped in the cooling system must be removed as follows.
•
Start the engine, warm up the engine thoroughly, and then stop the engine. Wait until the engine cools down.
•
Remove the radiator cap.
Inspect the coolant level.
If the coolant level is low, add coolant up to the bottom of
• the filler neck.
•
Install the radiator cap.
Inspect the cooling system for leaks.
○
The high pressure inside the water hose can cause coolant to leak [A] or the hose to burst if the line is not properly maintained. Visually inspect the hoses for signs of deterioration. Squeeze the hoses. A hose should not be hard and brittle, nor should it be soft or swollen.
Replace the hose if any fraying, cracks [B] or bulges [C] are noticed.
•
Check that the hoses are securely connected and clamps are tightened correctly.
Torque - Water Hose Clamp Screws: 1.5 N·m (0.15 kgf·m,
13 in·lb)
Engine Top End
•
Lay a straightedge [A] across the lower surface of the head at several different points, and measure warp by inserting a thickness gauge [B] between the straightedge and the head.
If warp exceeds the service limit, repair the mating surface. Replace the cylinder head if the mating surface is badly damaged.
Cylinder Head Warp
Service Limit: 0.03 mm (0.0012 in.)
Periodic Maintenance Procedures
NOTE
○
Measure the cylinder inside diameter when the cylinder is cold (room or ambient temperature).
•
Visually Inspect the inside of the cylinder for scratches and abnormal wear.
If the cylinder is damaged or badly worn, replace it with a new one.
•
Since there is a difference in cylinder wear in different directions, take a side-to-side and a front-to back measurement shown in the figure.
If any of the cylinder inside diameter measurements exceeds the service limit, the cylinder must be replaced with a new one since the PLATING cylinder cannot be bored or honed.
(A): KX125 - 15 mm (0.6 in.)
KX250 - 30 mm (1.2 in.)
Cylinder Inside Diameter
KX125:
Standard 54.010
∼
54.025 mm (2.1264
∼
2.1270
in.), and less than 0.01 mm (0.0004
in.) difference between any two measurements.
Service Limit 54.10 mm (2.130 in.), or more than
0.05 mm (0.020 in.) difference between any two measurements.
KX250:
Standard 66.400
∼
66.415 mm (2.6142
∼
2.6148
in.), and less than 0.01 mm (0.0004
in.) difference between any two measurements.
Service Limit 66.46 mm (2.617 in.), or more than
0.05 mm (0.020 in.) difference between any two measurements.
•
Measure the outside diameter of the piston 15.0 mm (0.59
in.) (KX125) or 20.5 mm (0.81 in.) (KX250) [A] up from the bottom of the piston at a right angle to the direction of the piston pin.
If the measurement is under the service limit, replace the piston.
(A): KX125 - 15.0 mm (0.59 in.)
KX250 - 20.5 mm (0.81 in.)
Periodic Maintenance Procedures
Piston Diameter
KX125:
Standard: 53.955
∼
53.970 mm (2.1242
∼
2.1248
in.)
Service Limit: 53.81 mm (2.118 in.)
KX250:
Standard: 66.336
∼
66.351 mm (2.6116
∼
2.6122
in.)
Service Limit: 66.19 mm (2.606 in.)
The piston-to-cylinder clearance is measured whenever a piston or cylinder is replaced with a new one. The standard piston-to-cylinder clearance must be adhered to whenever the cylinder is replaced.
If only a piston is replaced, the clearance may exceed the standard slightly. But it must not be less than the minimum, in order to avoid piston seizure.
The most accurate way to find the piston clearance is by making separate piston and cylinder diameter measurements and then computing the difference between the two values. Measure the piston diameter as just described, and measure the cylinder diameter at the very bottom of the cylinder.
Piston/Cylinder Clearance
Standard:
KX125: 0.040
∼
0.070 mm (0.0016
∼
0.0028 in.)
KX250: 0.049
∼
0.079 mm (0.0023
∼
0.0031 in.)
Periodic Maintenance Procedures
•
Visually inspect the piston rings and the piston ring grooves.
If the rings are worn unevenly or damaged, they must be replaced.
If the piston ring grooves are worn unevenly or damaged, the piston must be replaced and fitted with new rings.
•
Inspect for uneven groove wear by inspecting the ring seating.
•
The rings should fit perfectly parallel to the groove surfaces. If not, the piston must be replaced.
•
With the piston ring in its groove, make several measurements with a thickness gauge [A] to determine piston ring/groove clearance.
If the clearance exceeds the service limit, measure the thickness of the piston ring
If the ring has worn down to less than the service limit, replace the ring; if the groove width exceeds the service limit, replace the piston.
Piston Ring/Groove Clearance
KX125:
Standard: 0.015
∼
0.050 mm (0.0006
∼
0.0020 in.)
Service Limit: 0.15 mm (0.0059 in.)
KX250:
Standard: 0.025
∼
0.060 mm (0.0010
∼
0.0024 in.)
Service Limit: 0.16 mm (0.006 in.)
Piston Ring Thickness
KX125:
Standard: 0.980
∼
0.995 mm (0.0386
∼
0.0392 in.)
Service Limit: 0.91 mm (0.036 in.)
KX250:
Standard: 0.970
∼
0.985 mm (0.0382
∼
0.0388 in.)
Service Limit: 0.90 mm (0.035 in.)
Piston Ring Groove Width
KX125:
Standard: 1.01
∼
1.03 mm (0.0398
∼
0.0406 in.)
Service Limit: 1.11 mm (0.044 in.)
KX250:
Standard: 1.01
∼
1.03 mm (0.0398
∼
0.0406 in.)
Service Limit: 1.11 mm (0.044 in.)
Periodic Maintenance Procedures
•
Place the piston ring [A] inside the cylinder [B], using the piston to locate the ring squarely in place.
•
Set it close to the bottom of the cylinder, where cylinder wear is low.
•
Measure the gap between the ends of the ring with a thickness gauge [C]
If the gap is wider than the service limit, the ring is overworn and must be replaced.
Piston Ring End Gap
KX125:
Standard:
Service Limit:
KX250:
Standard:
Service Limit:
0.35
∼
0.55 mm (0.0138
∼
0.0217 in.)
0.85 mm (0.033 in.)
0.25
∼
0.45 mm (0.0098
∼
0.0177 in.)
0.75 mm (0.030 in.)
•
Visually inspect the snap ring [A] still fitted in place.
If the ring shows weakness or deformation, replace the ring. Also if the pin hole groove shows excessive wear, replace the piston.
•
Measure the diameter of the piston pin [B] with a micrometer.
If the piston pin diameter is less than the service limit at any point, replace the piston pin.
•
Using a cylinder gauge, measure the diameter of both of piston pin holes [C] in the piston and the inside diameter of the connecting rod small end.
If either piston pin hole diameter exceeds the service limit, replace the piston.
If the connecting rod small end inside diameter exceeds
• the service limit, replace the crankshaft assembly.
Inspect the needle bearing [D].
○
The rollers in a needle bearing normally wear very little, and wear is difficult to measure. Instead of measuring, inspect the bearing for abrasion, color change, other damage.
If there is any doubt as to the condition of a needle bearing, replace the bearing and piston pin.
Periodic Maintenance Procedures
Piston Pin Diameter
KX125
Standard: 14.995
∼
15.000 mm (0.5904
∼
0.5906
in.)
Service Limit: 14.96 mm (0.589 in.)
KX250
Standard: 17.995
∼
18.000 mm (0.7085
∼
0.7087
in.)
Service Limit: 17.96 mm (0.707 in.)
Piston Pin Hole Diameter
KX125
Standard: 15.001
∼
15.011 mm (0.5906
∼
0.5910
in.)
Service Limit: 15.08 mm (0.594 in.)
KX250
Standard: 18.001
∼
18.011 mm (0.7087
∼
0.7091
in.)
Service Limit: 18.08 mm (0.712 in.)
Connecting Rod Small End Inside Diameter
KX125
Standard: 19.003
∼
19.014 mm (0.7481
∼
0.7486
in.)
Service Limit: 19.05 mm (0.750 in.)
KX250
Standard: 22.003
∼
22.012 mm (0.8663
∼
0.8666
in.)
Service Limit: 22.05 mm (0.868 in.)
•
Refer to the Exhaust Valve (KIPS) section in the Engine
Top End chapter.
•
The exhaust system, in particular, the baffle is equipped in the muffler body to reduce exhaust noise and conduct the exhaust gases away from the rider while minimizing power loss. If carbon has built up inside the baffle, exhaust efficiency is reduced, causing engine performance to drop.
•
Check the muffler body conditions.
If the muffler body is badly damaged, dented, cracked or rusted, replace it. Replace the muffler baffle if the exhaust noise becomes too loud or engine performance drops.
Periodic Maintenance Procedures
•
Remove the muffler body.
•
Remove the muffler pipe mounting bolts [A], and pull the muffler pipe [B] from the muffler body.
•
Unscrew the inner pipe bolts [A].
•
Pull the inner pipe [B] from the muffler body.
•
Pull off the old muffler baffle, and install the new muffler baffle [A] into the muffler body.
•
Apply silicone sealant to the circumference [B] of the muffler pipe and inner pipe.
•
Apply a non-permanent locking agent to the pipe mounting bolts.
•
Tighten:
Torque - Inner Pipe Mounting Bolts: 8.8 N·m (0.9 kgf·m, 78 in·lb)
Muffler Pipe Mounting Bolts: 8.8 N·m (0.9 kgf·m,
78 in·lb)
•
Install the muffler body and tighten the bolts.
Torque - Muffler Mounting Bolts: 8.8 N·m (0.9 kgf·m, 78 in·lb)
Engine Right Side
WARNING
To avoid a serious burn, never touch the hot engine or exhaust chamber during clutch adjustment.
•
Clutch Lever Free Play Inspection
Slide the clutch lever dust cover [A] out of place.
•
Inspect that the clutch cable upper end is fully seated in the adjuster [B].
•
Inspect that the clutch lever [C] has 2
∼
3 mm (0.08
∼
0.12
in.) of play [D].
If it does not, adjust the clutch lever free play.
Periodic Maintenance Procedures
•
Clutch Lever Free Play Adjustment
Slide the clutch lever dust cover out of place.
•
Loosen the knurled locknut [A].
•
Turn the adjuster [B] so that the clutch lever will have 2
∼
3 mm (0.08
∼
0.12 in.) of play [C].
NOTE
○
Be sure that the outer cable end at the clutch lever is fully seated in the adjuster at the clutch lever, or it could slip into the place later, creating enough cable play to prevent clutch disengagement.
•
Tighten the locknut.
•
If it cannot be done, loosen the locknut [A] at the lower of the clutch cable, and turn the adjusting nut [B] so that clutch lever has 2
∼
3 mm (0.08
∼
0.12 in.) of play.
•
After the adjustment is made, tighten the locknut, and start the engine and check that the clutch does not slip and that it release properly.
Friction and Steel Plates Wear, Damage Inspection
•
Visually inspect the friction and steel plates to see if they show any signs of seizure, or uneven wear.
If any plates show signs of damage, replace the friction plates and steel plates as a set.
•
Measure the thickness [A] of the friction plates [B] and steel plates with vernier calipers.
If they have worn past the service limit, replace them with new ones.
Friction Plate Thickness
KX125:
Standard: 2.72
∼
2.88 mm (0.107
∼
0.113 in.)
Service Limit: 2.6 mm (0.102 in.)
KX250:
Standard: 2.92
∼
3.08 mm (0.115
∼
0.121 in.)
Service Limit: 2.8 mm (0.110 in.)
Steel Plate Thickness
KX125:
Standard: 1.5
∼
1.7 mm (0.059
∼
0.067 in.)
Service Limit: 1.4 mm (0.055 in.)
KX250:
Standard: 1.46
∼
1.74 mm (0.057
∼
0.069 in.)
Service Limit: 1.36 mm (0.054 in.)
Periodic Maintenance Procedures
Friction and Steel Plate Warp Inspection
•
Place each friction plate or steel plate on a surface plate, and measure the gap between the surface plate [A] and each friction plate or steel plate [B] with a thickness gauge
[C]. The gap is the amount of friction or steel plate warp.
If any plate is warped over the service limit, replace it with a new one.
Friction and Steel Plates Warp
Standard:
Friction Plate 0.15 mm (0.006 in.) or less
Steel Plate
Service Limit:
0.2 mm (0.008 in.) or less
Friction Plate 0.3 mm (0.012 in.)
Steel Plate 0.3 mm (0.012 in.)
Engine Bottom End/Transmission
In order for the transmission and clutch to function properly, always maintain the transmission oil at the proper level and change the oil periodically.
WARNING
Motorcycle operation with insufficient, deteriorated, or contaminated transmission oil will accelerated wear and may result in transmission seizure, and injury.
Transmission Oil Level Inspection
•
Situate the motorcycle so that it is perpendicular to the ground.
•
If the motorcycle has just been used, wait several minutes until the oil settles.
•
Inspect that the oil level comes up between the upper level [A] and lower level [B] through the oil level gauge
[C] on the clutch cover.
If the oil level is too high, remove the excess oil through the oil filler opening using a syringe or some other suitable device.
If the oil level is too low, add the correct amount of oil.
Use the same type and make of oil that is already in the engine.
NOTE
○
If the transmission oil type and make are unknown, use any brand of the specified oil to top up the level in preference to running the engine with the oil level low. Then at your earliest convenience, change the oil completely.
Periodic Maintenance Procedures
•
Transmission Oil Change
•
Warm up the engine thoroughly so that the oil will pick up any sediment and drain easily. Then stop the engine.
•
Place an oil pan beneath the engine.
Remove the engine oil drain plug [A] on the bottom of the engine, and let the oil drain completely.
NOTE
○
Hold the motorcycle upright so that the oil may drain completely.
•
Replace the gasket at the drain plug with a new one.
•
After the oil has completely drained out, install the drain plug with the gasket, and tighten it.
Torque - Engine Oil Drain Plug: 20 N·m (2.0 kgf·m, 14.5 ft·lb)
•
Fill the transmission with a good quality engine oil specified below.
•
Inspect the oil level.
Recommended Transmission Oil
Grade API SE, SF or SG
Viscosity
API SH, SJ or SL with JASO MA
SAE10W-40
Capacity KX125: 0.7 L (0.74 US qt.)
KX250: 0.85 L (0.90 US qt.)
NOTE
○
Although 10W-40 engine oil is the recommended oil for most conditions, the oil viscosity may need to be changed to accommodate atmospheric conditions in your riding area.
Wheels/Tires
•
Using tire air pressure gauge [A], measure the tire pressure when the tires are cold.
Adjust the tire air pressure to suit track conditions and rider preference, but do not stray too far from the recommended pressure.
Tire Pressure Track Condition
When the track is wet, muddy, sandy or slippery, reduce the tire pressure to increase the tire tread surface on the ground.
When the track is pebbly or hard, increase the tire pressure to prevent damage or punctures, though the tires will skid more easily.
80 kPa (0.8 kgf/cm²,
11 psi)
↑
↓
100 kPa (1.0 kgf/cm²,
14 psi)
Periodic Maintenance Procedures
As the tire tread wears down, the tire becomes more susceptible the puncture and failure.
•
Remove any imbedded stones or other foreign particles from the tread.
•
Visually inspect the tire for cracks and cuts, replacing the tire in case of bad damage. Swelling or high spots indicate internal damage, requiring tire replacement.
WARNING
To ensure safe handling and stability, use only the recommended standard tires for replacement, inflated to the standard pressure.
NOTE
○
Check and balance the wheel when a tire is replaced with a new one.
Standard Tire
KX125
Front:
Size:
Make:
80/100-21 51M
DUNLOP
Type:
(KX125-M1
∼
M2) D739FA, Tube (EUR) D755FJ,
Tube
(KX125-M3
∼
) D742F, Tube (EUR) D755FJ,
Tube
Rear:
Size:
Make:
100/90-19 57M
DUNLOP
Type:
(KX125-M1
∼
M2) D739, Tube (EUR) D755G, Tube
(KX125-M3
∼
) D756, Tube (EUR) D755G, Tube
KX250:
Front:
Size:
Make:
Type:
Rear:
80/100-21 51M
BRIDGESTONE (EUR) DUNLOP
M601, Tube (EUR) D755FJ, Tube
Size:
Make:
Type:
110/90-19 62M
BRIDGESTONE (EUR) DUNLOP
M602, Tube (EUR) D755J, Tube
EUR: Europe Model
Periodic Maintenance Procedures
•
Inspect that all the spokes are tightened evenly.
If spoke tightness is uneven or loose, tighten the spoke nipples evenly.
Torque - Spoke Nipples: 2.2 N·m (0.22 kgf·m, 19 in·lb)
•
Inspect the rim runout.
WARNING
If any spoke breaks, it should be replaced immediately. A missing spoke places an additional load on the other spokes, which will eventually cause other spokes to break.
•
Place the jack under the frame so that the front/rear wheel off the ground.
Special Tool - Jack: 57001-1238
•
Inspect the rim for small cracks, dents, bending, or warping.
If there is any damage to the rim, it must be replaced.
•
Set a dial gauge against the side of the rim, and rotate the rim to measure the axial runout [A]. The difference between the highest and lowest dial readings is the amount of runout.
•
Set a dial gauge against the outer circumference of the rim, and rotate the rim to measure radial runout [B]. The difference between the highest and lowest dial readings is the amount of runout.
If rim runout exceeds the service limit, check the wheel bearings first. Replace them if they are damaged. If the problem is not due to the bearings, correct the rim warp
(runout). A certain amount of rim warp can be corrected by recentering the rim. Loosen some spokes and tighten others within the standard torque to change the position of different parts of the rim. If the rim is badly bent, however, it must be replaced.
Rim Runout (with tire installed)
Standard:
Axial
Radial
Service Limit:
TIR 1.0 mm (0.04 in.) or less
TIR 1.0 mm (0.04 in.) or less
Axial
Radial
TIR 2 mm (0.08 in.)
TIR 2 mm (0.08 in.)
•
Refer to the Hub Bearing Inspection in the Wheels/Tires chapter.
Periodic Maintenance Procedures
Final Drive
Drive Chain Slack Inspection
•
Raise the rear wheel off the ground, rotate the rear wheel to find the place where the chain is tightest (because it wears unevenly).
Special Tool - Jack: 57001-1238
•
Inspect the wheel alignment (see Wheel Alignment Inspection in the Final Drive chapter), and adjust it if necessary (see Wheel Alignment Adjustment in the Final Drive chapter).
NOTE
○
Clean the drive chain if it is dirty, and lubricate it if it appears dry.
•
Rotate the rear wheel to find the position where the chain is tightest.
•
Measure the space (chain slack) [A] between the chain and the swing-arm at the rear of the chain slipper as shown.
If the drive chain slack exceeds the standard, adjust it.
Chain Slack
Standard: 52
∼
62 mm (2.05
∼
2.44 in.)
•
Drive Chain Slack Adjustment
Loosen the left and right chain adjuster locknuts [A].
•
Remove the cotter pin [B] and loosen the axle nut [C].
If the chain is too tight, back out the left and right chain adjusting bolts [D] evenly, and push the wheel forward until the chain is too loose.
If the chain is too loose, turn both chain adjusting bolts evenly until the drive chain has the correct amount of slack. To keep the chain and wheel properly aligned, the rear end of the left chain adjuster should align with the same swingarm mark [E] as the right chain adjuster rear end [F].
•
Inspect the wheel alignment.
•
Tighten both chain adjuster locknuts securely.
•
Tighten the axle nut.
Torque - Rear Axle Nut: 108 N·m (11.0 kgf·m, 80 ft·lb)
•
Rotate the wheel, measure the chain slack again at the tightest position, and readjust if necessary.
•
Install a new cotter pin [A] through the axle nut and axle, and spread its ends.
Periodic Maintenance Procedures
NOTE
○
When inserting the cotter pin, if the slots in the nut do not align with the cotter pin hole in the axle shaft, tighten the nut clockwise [A] up to next alignment.
○
It should be within 30 degree.
○
Loosen once tighten again when the slot goes past the nearest hole.
WARNING
If the axle nut is not securely tightened, or the cotter pin is not installed, an unsafe riding condition may result.
•
Inspect the rear brake (see Brakes chapter).
NOTE
○
In wet and muddy conditions, mud sticks to the chain and sprockets resulting in an overly tight chain, and the chain may break. To prevent this, adjust the chain to 62
∼
72 mm (2.44
∼
2.83 in.) of slack whenever necessary.
•
Rotate the rear wheel to inspect the drive chain for damaged rollers, and loose pins and links.
If there is any irregularity, replace the drive chain.
Lubricate the drive chain if it appears dry.
A. Bushing
B. Roller
C. Pin
D. Pin Link
E. Roller Link
•
Stretch the chain taut by hanging a 98 N (10 kgf, 20 lb) weight [A] on the chain.
•
Measure the length of 20 links [B] on the straight part [C] of the chain from the pin center of the 1st pin to the pin center of the 21st pin. Since the chain may wear unevenly, take measurements at several places.
Chain 20-link Length
Standard: 317.5
∼
318.2 mm (12.50
∼
12.53 in.)
Service Limit: 323 mm (12.72 in.)
If any measurements exceed the service limit, replace the chain. Also, replace the front and rear sprockets when the drive chain is replaced.
Periodic Maintenance Procedures
WARNING
If the drive chain wear exceeds the service limit, replace the chain or an unsafe riding condition may result. A chain that breaks or jumps off the sprockets could snag on the engine sprocket or lock the rear wheel, severely damaging the motorcycle and causing it to go out of control.
Standard Chain
Make:
Type:
Link:
DAIDO
D.I.D 520DMA2
KX125-M1 112 Links
KX125-M2
∼
114 Links
KX250 114 Links
•
If the chain appears especially dirty, it should be cleaned before lubrication with high flash-point solvent.
•
If a special lubricant is not available, a heavy oil such as
SAE90 is preferred to a lighter oil because it will stay on the chain longer and provide better lubrication.
•
Apply oil to the sides of the rollers so that oil will penetrate to the rollers and bushings.
•
Wipe off any excess oil.
Oil applied area [A]
•
Visually inspect the front and rear sprocket teeth for wear and damage.
If they are worn as illustrated or damaged, replace the sprocket.
A. Worn Tooth (Engine Sprocket)
B. Worn Tooth (Rear Sprocket)
C. Direction of Rotation
NOTE
○
If a sprocket requires replacement, the chain is probably worn also. When replacing a sprocket, inspect the chain.
Periodic Maintenance Procedures
•
Using the jack, raise the rear wheel off the ground.
Special Tool - Jack: 57001-1238
•
Set a dial gauge [A] against the rear sprocket [B] near the teeth as shown and rotate [C] the rear wheel to measure the sprocket runout (warp). The difference between the highest and lowest dial gauge readings is the amount of runout (warp).
If the runout exceeds the service limit, replace the rear sprocket.
Rear Sprocket Warp (Runout)
Standard: TIR 0.4 mm (0.016 in.) or less
Service Limit: TIR 0.5 mm (0.020 in.)
Brakes
•
Adjust the front brake lever [A] to suit you.
•
Slide the brake lever dust cover [B] out of place.
•
Loosen the adjuster locknut [C] and turn the adjuster [D] to either side.
•
After adjustment, tighten the locknut.
WARNING
Always maintain proper brake adjustment. If adjustment is improper, the brake could drag and overheat. This could damage the brake assembly and possibly lock the wheel resulting in loss of control.
Periodic Maintenance Procedures
In accordance with the Periodic Maintenance Chart, inspect the brake fluid level in the front or rear brake fluid reservoirs.
•
Check the brake fluid level in the front or rear brake reservoir [A].
NOTE
○
Hold the reservoir horizontal when checking brake fluid level.
○
The front or rear reservoir must be kept above the lower level line [B]. If the fluid level in front or rear reservoir is lower than the lower level line, fill the reservoir to the upper level line. Inside the reservoir is stopped end showing the upper level line [C].
Periodic Maintenance Procedures
In accordance with the Periodic Maintenance Chart, change the brake fluid. The brake fluid should also be changed if it becomes contaminated with dirt or water.
Furthermore, the brake fluid should be changed to bleed the air quickly and completely whenever the brake line parts are removed.
WARNING
Change the brake fluid in the brake line completely if the brake fluid must be refilled but the type and brand of the brake fluid that already is in the reservoir are unidentified. After changing the fluid, use only the same type and brand of fluid thereafter.
Mixing different types and brand of brake fluid lowers the brake fluid boiling point and could cause the brake to be ineffective. It may also cause the rubber brake parts to deteriorate.
Recommended Disc Brake Fluid
Type:
Front
Rear
DOT3 or DOT4
DOT4
NOTE
○
The procedure to change the front brake fluid. Changing the rear brake fluid is the same as for the front brake.
•
Level the brake fluid reservoir.
•
Remove the reservoir cap.
•
Remove the rubber cap [A] on the bleed valve [B].
•
Attach a clear plastic hose to the bleed valve on the caliper, and run the other end of the hose into a container.
•
For KX125/250-M2 model
∼
; as shown in the figure.
Periodic Maintenance Procedures
•
Change the brake fluid as follows:
○
Repeat this operation until fresh brake fluid comes out from the plastic hose or the color of the fluid changes.
1. Open the bleed valve [A]
2. Apply the brake and hold it [B]
3. Close the bleed valve [C]
4. Release the brake [D]
○
Fill the reservoir with fresh specified brake fluid.
NOTE
○
The fluid level must be checked often during the changing operation and replenished with fresh brake fluid. If the fluid in the reservoir runs out any time during the changing operation, the brakes will need to be bled since air will have entered the brake line.
•
Remove the clear plastic hose.
•
Tighten the bleed valves, and install the rubber caps.
Torque - Caliper Bleed Valve: 7.8 N·m (0.8 kgf·m, 69 in·lb)
•
After changing the fluid, check the brake for good braking power, no brake drag, and no fluid leakage.
If necessary, bleed the air from the lines.
WARNING
Do not mix two brands of fluid. Change the brake fluid in the brake line completely if the brake fluid must be refilled but the type and brand of the brake fluid that is already in the reservoir are unidentified.
•
Remove the brake pad (see Brake Pad Removal in
Brakes chapter).
•
Inspect the lining thickness and condition of the pads in each caliper.
If either pad is damaged, replace both pads in the caliper as a set.
If the lining thickness [A] of either pad is less than the service limit [B], replace both pads in the caliper as a set.
Lining Thickness
Standard:
Front
Rear
3.8 mm (0.150 in.)
6.4 mm (0.252 in.)
Service Limit:
Front 1 mm (0.04 in.)
Rear 1 mm (0.04 in.)
•
Install the brake pad (see Brake Pad Installation in Brakes chapter).
•
Tighten:
Torque - Brake Pad Bolt: 18 N·m (1.8 kgf·m, 13 ft·lb)
•
Refer to the Master Cylinder section in the Brakes chapter.
•
Refer to the Calipers section in the Brakes chapter.
Periodic Maintenance Procedures
•
Inspect the brake hose and fittings for deterioration, cracks and signs of leakage.
○
The high pressure inside the brake line can cause fluid to leak [A] or the hose to burst if the line is not properly maintained. Bend and twist the rubber hose while examining it.
Replace the hose if any cracks [B] or bulges [C] are noticed.
Tighten any loose fittings.
CAUTION
Brake fluid quickly ruins painted surfaces; any spilled fluid should be completely washed away immediately.
•
When removing the brake hose, take care not to spill the brake fluid on the painted or plastic parts.
•
When removing the brake hose temporarily secure the end of the brake hose to some high place to keep fluid loss to a minimum.
•
Immediately wash away any brake fluid that spills.
•
Remove each banjo bolts [A] and washers [B].
•
Replace the washers with new ones.
For Front Brake Hose
•
Remove
Bolts [A]
Brake Hose Clamps [B]
Periodic Maintenance Procedures
For Rear Brake Hose
•
Remove:
Master Cylinder [A]
Hose Clamps [B]
•
When installing the hoses, avoid sharp bending, kinking, flattening or twisting, and route the hoses according to
Cable, Wire, and Hose Routing section in the Appendix chapter.
•
Tighten the banjo bolts on the hose fittings.
Torque - Brake Hose Banjo Bolts: 25 N·m (2.5 kgf·m, 18 ft·lb)
•
Fill the brake line after installing the brake hose (see
Brake Fluid Change).
Suspension
•
Visually inspect the front fork for oil leakage, scoring or scratches on the outer surface of the inner tube [A].
If necessary, repair any damage.
•
Nick or rust damage can sometimes be repaired by using a wet-stone to remove sharp edges or raised areas which cause seal damage.
If the damage is not repairable, replace the inner tube.
Since damage to the inner tube damages the oil seal, replace the oil seal whenever the inner tube is repaired or replaced.
•
Temporarily assemble the inner and outer tubes, and pump them back and forth manually to check for smooth operation.
CAUTION
If the inner tube is badly bent or creased, replace it.
Excessive bending, followed by subsequent straightening, can weaken the inner tube.
•
For KX125/250-M2 model
∼
; as shown in the figure.
Periodic Maintenance Procedures
•
Loosen the front fork upper clamp bolts.
•
Place the handlebar on one side, and loosen the fork top
• plug.
Remove the front fork.
•
Hold the inner tube lower end in a vise.
•
Disassemble the top plug from the outer tube.
•
Push the outer tube all the way down away from the top plug and hold it there throughout the following procedure.
○
For KX125/250-M1 model, pull the fork spring [A] away from the top plug a little and slip the spanner wrench [B] in on top of the spring seat and under the push rod nut
[C].
•
Use wrenches on the rod nut and the top plug [A] to loosen the push rod nut.
•
Remove the top plug from the push rod.
•
Lift the fork spring [B] and its top spring seat [C] out of the outer tube.
•
For KX125/250-M2 model
∼
; as shown in the figure.
•
Take the rebound damping adjuster rod [A] out of the push rod.
Periodic Maintenance Procedures
•
Hold the fork tube [A] upside down over a clean container
[B] and pump it to drain the oil.
NOTE
○
To discharge the fork oil, pump the push rod up [C] and down ten times.
•
Hold the fork tube upright, press the outer tube and the push rod all the way down.
•
Insert the rebound damping adjuster rod into the push rod.
NOTE
○
The spring should not be installed.
•
Fill the specified oil to the outer tube.
Recommended Oil
KHL15-10 (KAYABA 01) or equivalent
Front Fork Oil Capacity
KX125-M1:
KX125-M2
∼
:
KX250-M1:
KX250-M2
∼
:
652 ±4 mL (22.04 ±0.14 US oz)
565 ±4 mL (19.10 ±0.14 US oz)
664 ±4 mL (22.45 ±0.14 US oz)
578 ±4 mL (19.54 ±0.14 US oz)
NOTE
○
While doing this, take care to keep the oil level topped off so that it stays above the two large holes [A] near the top of the inner tube [B].
•
Screw the fork piston rod puller [A] onto the end of the push rod.
Special Tool - Fork Piston Rod Puller, M12 x 1.25: 57001
-1289
•
Purge the air from the fork cylinder by gently moving the piston rod puller up and down five times.
•
Remove the fork piston rod puller.
Periodic Maintenance Procedures
•
Purge the air from between the inner and outer tubes by pumping the outer tube [A] up and down.
•
After purging the air from the assembly, let it sit for about five minutes so that any suspended air bubbles can sur-
• face.
•
Install the spring guide.
Screw the push rod nut.
•
Adjust the oil level.
○
With the fork fully compressed, put the oil level gauge [A] and the stopper [B], and inspect the distance from the top of the inner tube to the oil.
Special Tool - Fork Oil Level Gauge: 57001-1290
Oil Level (fully compressed, without spring)
Standard
KX125-M1: 133
∼
137 mm (5.24
∼
5.39 in.)
KX125-M2
∼
:
KX250-M1:
KX250-M2
∼
:
103
∼
107 mm (4.06
∼
4.21 in.)
123
∼
127 mm (4.84
∼
5.00 in.)
86
∼
90 mm (3.39
∼
3.54 in.)
Adjustable Range
KX125/250-M1:
KX125/250-M2
∼
:
100
∼
145 mm (3.94
∼
5.71 in.)
70
∼
120 mm (2.76
∼
4.72 in.)
If no oil is drawn out, there is insufficient oil in the outer tube. Pour in enough oil, then drawn out the excess oil.
•
Install the parts removed (see Front Fork Assembly in the
Suspension chapter).
•
Refer to the Rear Suspension (Uni-Trak) section in the
Suspension chapter for Rear Shock Absorber Disassembly (Oil Change) and Assembly.
•
Inspect the uni-trak component parts for wear periodically, or whenever excessive play is suspected.
•
Using the jack under the frame, raise the rear wheel off the ground.
Special Tool - Jack: 57001-1238
•
Push and pull on the swingarm [A], up and down, to check for wear.
A small amount of play on the swingarm is normal and no corrective action is needed. However, if excessive play is felt, remove the uni-trak parts from the frame and check for wear.
•
Refer to the Swingarm Bearing Installation, and Tie-Rod and Rocker Arm Bearing Installation in the Suspension chapter.
Periodic Maintenance Procedures
•
Visually inspect the drive chain guide [A] and replace it if excessively worn or damaged.
•
Visually inspect the upper and lower chain slippers [A] on the swingarm [B] and replace them if worn or damaged.
Steering
Steering Play Inspection
•
Using the jack, raise the front wheel off the ground.
Special Tool - Jack: 57001-1238
•
With the front wheel pointing straight ahead, alternately nudge each end of the handlebar. The front wheel should swing fully left and right from the force of gravity until the fork hits the stop.
If the steering binds or catches before the stop, check the routing of the cables, hoses, and harnesses.
If the steering feels tight, adjust or lubricate the steering.
•
Feel for steering looseness by pushing and pulling the forks.
If you feel looseness, adjust the steering.
•
For KX125/250-M2 model
∼
; as shown in the figure.
Steering Play Adjustment
•
Using the jack, raise the front wheel off the ground.
Special Tool - Jack: 57001-1238
Periodic Maintenance Procedures
•
KX125-M1
∼
M3/KX250-M1
∼
M2;
•
Slide the holder belt [A] out off.
Remove number plate bolt [B] and number plate [C].
•
Remove:
Handlebar Holder Bolts [A]
Handlebar Holder [B]
Handle Bar [C]
KX125M6F
∼
;
•
Remove:
Number Plate [A]
Pad [B]
•
Remove:
Handlebar Holder Bolts [A]
Handlebar Holders [B]
Handlebar [C]
•
Loosen the front fork upper clamp bolts [A], and remove the steering stem head nut [B] and steering stem head
[C].
Periodic Maintenance Procedures
•
Turn the steering stem locknut [A] with the steering stem nut wrench [B] to obtain the proper adjustment.
If the steering is too tight, loosen the stem locknut a fraction of a turn; if the steering is too loose, tighten the locknut a fraction of a turn.
Special Tool - Steering Stem Nut Wrench: 57001-1100
NOTE
○
Turn the locknut 1/8 turn at a time maximum.
•
Install the steering stem head.
•
Tighten the following:
Torque - Steering Stem Head Nut: 98 N·m (10.0 kgf·m, 72 ft·lb)
Front Fork Clamp Bolts: (Upper): 20 N·m (2.0
kgf·m, 14.5 ft·lb)
NOTE
○
Tighten the two clamp bolts alternately two times to ensure even tightening torque.
•
Check the steering again.
If the steering is too tight or too loose, repeat the adjustment as mentioned above.
KX125-M1
∼
M3/KX250-M1
∼
M2;
•
Install the handlebar [A] on the handlebar holder as shown.
Same Length [B]
Bridge Bar [C]
•
Install the handlebar holder [A] together with the handlebar so that the cut side [B] on the holder points at the front.
•
Tighten the handlebar holder bolts [C].
Torque - Handlebar Holder Bolts: 25 N·m (2.5 kgf·m, 18 ft·lb)
○
Tighten the holder bolts, rear first and then the front. If the handlebar holder is correctly installed, there will be no gap at the rear and a gap at the front after tightening.
•
Install the number plate.
Periodic Maintenance Procedures
KX125M6F
∼
;
•
Install the handlebar [A] on the handlebar holder as shown.
Same Length [B]
Bridge Bar [C]
Protrusion of Graduation [D]
•
Install the handlebar holders [A] with handlebar.
○
Tighten the front and rear bolts [B] of the handlebar holders equally.
Torque - Handlebar Holder Bolts: 25 N·m (2.5 kgf·m, 18 ft·lb)
If the handlebar holders are correctly installed, there will be same amount of gap [C] on the front and rear side of the holder after the bolts tightening.
•
Install:
Pad
Number Plate
•
Remove the steering stem (see Steering Stem Removal in the Steering chapter).
•
Using a high-flash point solvent, wash the upper and lower tapered rollers in the cages, and wipe the upper and lower outer races, which are press-fitted into the frame head pipe, clean off grease and dirt.
•
Visually check the outer races and the rollers.
Replace the bearing assemblies if they show wear or damage.
•
Pack the upper and lower tapered roller bearings [A] in the cages with grease, and apply a light coat of grease to the upper and lower outer races.
•
Install the steering stem, and adjust the steering (see
Steering Stem, Stem Bearing Installation, Steering Adjustment in the Steering chapter).
Frame
•
Clean the frame with steam cleaner.
•
Visually inspect the frame and rear frame for cracks, dents, bending, or warp.
If there is any damage to the frame, replace it.
WARNING
A repaired frame may fail in use, possibly causing an accident. If the frame is bent, dented, cracked, or warped, replace it.
Periodic Maintenance Procedures
Electrical System
•
Remove the spark plug, and visually inspect it.
•
Clean the spark plug, preferably in a sandblasting device, and then clean off any abrasive particles. The plug may also be cleaned using a high-flash point solvent and a wire brush or other suitable tool.
If the spark plug electrodes are corroded or damaged, or if the insulator is cracked, replace the plug. Use the standard spark plug.
•
Measure the gap [A] with a wire-type thickness gauge.
If the gap is incorrect, carefully bend the side electrode
[B] with a suitable tool to obtain the correct gap.
Spark Plug Gap
Standard 0.7
∼
0.8 mm (0.028
∼
0.031 in.)
Periodic Maintenance Procedures
General Lubrication
•
Before lubricating each part, clean off any rusty spots with rust remover and wipe off any grease, oil, dirt, or grime.
•
Lubricate the points listed below with indicated lubricant.
NOTE
○
Whenever the vehicle has been operated under wet or rainy conditions, or especially after using a high-pressure water spray, perform the general lubrication.
Point: Lubricate with Engine Oil
Rear Brake Rod Joint
Drive Chain
Points: Lubricate with Grease.
Clutch Inner Cable Upper and Lower Ends [A]
Throttle Inner Cable Upper End
Swingarm Pivot
Tie-Rod Pivot
Rocker Arm Pivot
Steering Stem Bearing
Clutch Lever Pivot
Brake Lever Pivot
Kick Pedal
Shift Pedal
Cables: Lubricate with Rust Inhibitor.
Throttle Cable
Clutch Cable
•
With the cable disconnected at the both ends, the cable should move freely [A] within the cable housing.
If cable movement is not free after lubricating, if the cable is frayed [B], or if the cable housing is kinked [C], replace the cable.
Periodic Maintenance Procedures
Nut, Bolt, and Fastener Tightness
•
Inspect the tightness of bolts and nuts listed here. Also, check to see that each cotter pin is in place and in good condition.
NOTE
○
For the engine fasteners, check the tightness of them when the engine is cold (at room temperature).
If there are loose fasteners, retorque them to the specified torque following the specified tightening sequence.
Refer to the appropriate chapter for torque specifications.
If torque specifications are not in the appropriate chapter, see the Standard Torque Table. For each fastener, first loosen it by 1/2 turn, then tighten it.
If cotter pins are damaged, replace them with new ones.
Nut, Bolt and Fastener to be checked
Wheels:
Spoke Nipples
Front Axle Nut
Rear Axle Nut Cotter Pin
Rear Axle Nut
Final Drive:
Chain Adjuster Locknuts
Rear Sprocket Nuts
Brakes:
Front Master Cylinder Clamp Bolts
Caliper Mounting Bolts (Front)
Rear Master Cylinder Mounting Bolts
Rear Master Cylinder Joint Cotter Pin
Brake Lever Pivot Nut
Brake Pedal Mounting Bolt
Suspension:
Front Fork Clamp Bolts
Rear Shock Absorber Mounting Nuts
Swingarm Pivot Shaft Nut
Uni-Trak Link Nuts
Steering:
Steering Stem Head Nut
Handlebar Holder Bolts
Engine:
Engine Mounting Nuts
Engine Bracket Nuts
Cylinder Head Nuts
Shift Pedal Bolt
Muffler Bolt and Nut
Kick Pedal Bolt
Others:
Rear Frame Mounting Bolts
Front Fender Mounting Bolts
Table of Contents
3
Exploded View
KX125M:
Exploded View
No.
Fastener
1 Carburetor Holder Mounting Bolts
2 Carburetor Holding Clamp Screw
3 Reed Valve Screws
4 Carburetor Top Cover Screws
5. Throttle Cable
6. Throttle Grip
7. Spring
8. Retainer
9. Connector
10. Jet Needle Clip
11. Jet Needle
12. Throttle Valve
13. Choke Knob
14. Idle Adjusting Screw
15. Air Screw
16. Slow Jet
17. Main Jet
18. Needle Jet
19. Main Jet Holder
20. Float Valve Needle
21. Float
22. Carburetor Holder
23a. Reed Valve (KX125-M1 Model)
23b. Reed Valve (KX125-M2 Model
∼
)
G: Apply grease.
O: Apply oil.
N·m
8.8
1.5
1.0
3.0
Torque kgf·m
0.9
0.15
0.1
0.3
ft·lb
78 in·lb
13 in·lb
9 in·lb
26 in·lb
Remarks
Exploded View
KX250M:
Exploded View
No.
Fastener
1 Carburetor Holder Mounting Bolts
2 Carburetor Holding Clamp Screw
3 Reed Valve Screws
4 Throttle Sensor Bolt
5 Carburetor Top Cover Allen Bolts
6. Throttle Cable
7. Throttle Grip
8. Spring
9. Retainer
10. Connector
11. Jet Needle Clip
12. Jet Needle
13. Throttle Valve
14. Choke Knob
15. Idle Adjusting Screw
16. Spring
17. Air Screw
18. Slow Jet
19. Power Jet
20. Main Jet
21. Float Valve Needle
22. Float
23. Throttle Sensor
24. Fuel Cut Valve
25. Carburetor Holder
26. Reed Valve
G: Apply grease.
O: Apply oil.
N·m
8.8
1.5
1.0
2.0
3.9
Torque kgf·m
0.9
0.15
0.1
0.2
0.4
ft·lb
78 in·lb
13 in·lb
9 in·lb
17 in·lb
35 in·lb
Remarks
Exploded View
Exploded View
No Fastener
1 Rear Frame Mounting Bolts
2 Air Cleaner Duct Clamp Screw
3 Fuel Tap Plate Mounting Screws
4 Air Cleaner Duct Nuts
5 Air Cleaner Housing Bolts
6. Fuel Tank Cap
7. Fuel Tank
8. Fuel Tap
9. Element
10. Frame
11. Holder
12. Air Cleaner Duct
13. Air Cleaner Housing
14. Rear Frame
G: Apply grease.
O: High-quality foam-air-filter oil.
N·m
34
1.5
0.8
3.0
8.8
Torque kgf·m
3.5
0.15
0.08
0.3
0.9
ft·lb
25
13 in·lb
7 in·lb
26 in·lb
78 in·lb
Remarks
Specifications
KX125:
Item
Carburetor
Make/Type
Main Jet:
Throttle Valve Cutaway
Jet Needle
Jet Needle Clip Position
Slow Jet (Pilot Jet)
Air Screw (Turns out)
Service Fuel Level
(above the bottom edge of the carb. body)
Float Height
KX125-M1
Standard
KX125-M2 KX125-M3
∼
MIKUNI TMX38
#420
#5.75
6CHJ 11-82
3rd groove from the top
#40
2 1/2
10 ±1 mm (0.394 ±0.039 in.)
6CHJ 10-82
1 1/2
9.5 ±1 mm (0.374 ±0.039 in.)
Service Limit
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
KX250:
Item
Carburetor
Make/Type
Main Jet:
Power Jet:
Throttle Valve Cutaway
Jet Needle
Jet Needle Clip Position
Slow Jet (Pilot Jet)
Air Screw (Turns out)
Service Fuel Level
(above the bottom edge of the carb. body)
Float Height
Fuel Cut Valve
Throttle Sensor
KX250-M1
Standard
KEIHIN PWK38S
#165
#50
#8
NAFH
2nd groove from the top
#52
NALF
2 1 1/2
10.5 ±1 mm (0.413 ±0.039 in.)
6.5 ±1 mm (0.256 ±0.039 in.) see Electrical System chapter see Electrical System chapter
KX250-M2
Service Limit
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
Special Tools
Fuel Level Gauge, M18 × 1.0:
57001-122
Fuel Level Gauge:
57001-1577
Graduated Cylinder & Tube:
57001-1584
Throttle Grip and Cable
If the throttle grip has excessive free play due to cable stretch or misadjustment, there will be a delay in throttle response. Also, the throttle valve may not open fully at full throttle. On the other hand, if the throttle grip has no play, the throttle will be hard to control, and the idle speed will be erratic. Check the throttle grip play periodically in accordance with the Periodic Maintenance Chart, and adjust the play if necessary.
The throttle cable routing is shown in Cable, Wire and
Hose Routing in the Appendix chapter.
•
Refer to the Throttle Cable Inspection in the Periodic
Maintenance chapter.
•
Refer to the Throttle Cable Inspection in the Periodic
Maintenance chapter.
•
Install the throttle cable in accordance with the Cable,
Wire and Hose Routing section in the Appendix chapter.
•
After the installation, adjust each cable properly.
WARNING
Operation with an incorrectly routed or improperly adjusted cable could result in an unsafe riding condition.
•
Whenever the throttle cable is removed or in accordance with the Periodic Maintenance Chart, lubricate the these cables (see General Lubrication in the Periodic Maintenance chapter).
○
Apply a thin coating of grease to the cable upper end.
○
Use a commercially available pressure cable lubricator to lubricate these cables.
•
With the throttle cable disconnected at both ends, the cable should move freely [A] within the cable housing.
If cable movement is not free after lubricating, if the cable is frayed, or if the housing is kinked, replace the cable.
Carburetor
Since the carburetor regulates and mixes the fuel and air going to the engine, there are two general types of carburetor trouble: too rich a mixture (too much fuel), and too lean a mixture (too little fuel). Such trouble can be caused by dirt, wear, maladjustment, or improper fuel level in the float chamber. A dirty or damaged air cleaner can also alter the fuel to air ratio.
•
Refer to the Carburetor Inspection in the Periodic Maintenance chapter.
•
Refer to the Carburetor Inspection in the Periodic Maintenance chapter.
WARNING
Gasoline is extremely flammable and can be explosive under certain conditions. Always stop the engine and do not smoke. Make sure the area is well ventilated and free from any source of flame or sparks; this includes any appliance with a pilot light.
•
•
Turn the fuel tap to the OFF position.
Remove the fuel tank.
•
Remove the carburetor, and hold it in true vertical position on a stand. The fuel hose and carburetor cable do not have to be removed to inspect the fuel level.
•
Put the fuel tank on a bench, and connect the fuel tap to the carburetor using a suitable hose.
•
Remove the drain plug from the bottom of the float bowl, and screw a fuel level gauge [A] into the plug hole.
Special Tools - Fuel Level Gauge: 57001-1577 (KX125)
Graduated Cylinder & Tube: 57001-1584
Fuel Level Gauge, M18 × 1.0: 57001-122
(KX250)
•
Hold the gauge vertically against the side of the carburetor body so that the "zero" line [B] is several millimeters higher than the bottom edge [C] of the carburetor body.
•
Turn the fuel tap to the ON position to feed fuel to the carburetor.
•
Wait until the fuel level in the gauge settles.
Carburetor
•
Keeping the gauge [A] vertical, slowly lower the gauge to measure the actual fuel level [B] until the “zero” line [C] is even with the bottom edge [D] of the carburetor body.
NOTE
○
Do not lower the “zero” line below the bottom edge of the carburetor body. If the gauge is lowered and then raised again, the fuel level measure shows somewhat higher than the actual fuel level. If the gauge is lowered too far, dump the fuel out of it into a suitable container and start the procedure over again.
•
Read the fuel level in the gauge and compare it to the specification.
Service Fuel Level
(above the bottom edge of the carb.
body)
Standard: 10 ±1 mm (0.394 ±0.039 in.) (KX125)
10.5 ±1 mm (0.413 ±0.039 in.) (KX250)
If the fuel level is incorrect, adjust it.
•
Turn the fuel tap to the OFF position and remove the fuel level gauge.
•
Install the drain plug on the bottom of the float bowl.
WARNING
Gasoline is extremely flammable and can be explosive under certain conditions. Always stop the engine and do not smoke. Make sure the area is well-ventilated and free from any source of flame or sparks; this includes any appliance with a pilot light.
•
Remove the carburetor, and drain the fuel into a suitable container.
•
Remove the float bowl.
KX125:
Carburetor
•
Unscrew the pivot pin screw [A] and remove the float [B].
KX250:
•
Drive out the pivot pin [A] and remove the float [B].
•
Bend the tang [A] on the float arm very slightly to change the float height. Increasing the float height lowers the fuel level and decreasing the float height raises the fuel level.
Float Height
Standard: 9.5 ±1 mm (0.374 ±0.039 in.) (KX125)
6.5 ±1 mm (0.256 ±0.039 in.) (KX250)
NOTE
○
Float height [A] is the distance from the float bowl mating surface [B] of the carburetor body (with the gasket removed) to the top of the float [C]. Measure the height with the carburetor upside down.
○
Do not push the needle rod [D] in during the float height measurement.
•
Assemble the carburetor, and recheck the fuel level.
If the fuel level cannot be adjusted by this method, the float or the float valve is damaged.
Carburetor
WARNING
Gasoline is extremely flammable and can be explosive under certain conditions. Always stop the engine and do not smoke. Make sure the area is well-ventilated and free from any source of flame or sparks; this includes any appliance with a pilot light.
•
Turn the fuel tap to the OFF position and pull the fuel hose off the tap.
•
For KX250, disconnect the carburetor lead connector.
•
Loosen the clamps [A], and remove the carburetor from the end of the air cleaner duct, and then pull it out of the carburetor holder.
If necessary, do the following procedure.
○
Remove:
Seat
Right Side Cover
Silencer
Rear Frame Bolt [A]
○
Loosen the rear frame bolts [B], pull up the rear frame [C] with the air cleaner housing and remove the carburetor.
•
Drain the fuel from the float bowl by removing the drain plug. After draining, install the drain plug securely.
•
Unscrew the carburetor cap screws (KX125) or bolts
(KX250) [A].
Carburetor
•
Pull out the throttle valve assembly [A].
CAUTION
If the throttle valve is not removed from the cable, wrap it in a clean cloth to avoid damage.
•
After removing the carburetor, push a clean, lint-free towel into the carburetor holder and the air cleaner duct to keep dirt or other foreign material from entering.
WARNING
If dirt or dust is allowed to pass through into the carburetor, the throttle may become stuck, possibly causing an accident.
CAUTION
If dirt gets through into the engine, excessive engine wear and possibly engine damage will occur.
•
For KX250, lifting up the link shaft end [A] of the throttle sensor install the throttle valve assembly.
•
Being careful not to bend the throttle valve assembly or otherwise damage the jet needle. Check to see that the throttle valve [B] goes all the way down into the carburetor body, and slides smoothly.
•
Tighten:
Torque - Carburetor Top Cover Screws: 3.0 N·m (0.3 kgf·m,
26 in·lb) (KX125)
Carburetor Top Cover Allen Bolts: 3.9 N·m (0.4
kgf·m, 35 in·lb) (KX250)
•
When installing the carburetor into the carburetor holder, align the center [A] of the carburetor with the groove [B] on the holder.
•
Tighten the clamps securely.
Torque - Carburetor Holding Clamp Screw: 1.5 N·m (0.15
kgf·m, 13 in·lb)
Carburetor
•
Route the air vent and overflow hoses properly (see Cable, Wire and Hose Routing in the Appendix chapter).
CAUTION
Always keep the hoses free of obstruction, and make sure they do not get pinched by the chain or shock absorber.
•
•
For KX250, connect the carburetor lead connector.
After installing the carburetor, do the following.
○
Turn the fuel tap to the ON position, and check for fuel leakage from the carburetor.
WARNING
Fuel spilled from the carburetor is hazardous.
○
Adjust the following items if necessary:
Throttle Cable
Idle Speed
WARNING
Gasoline is extremely flammable and can be explosive under certain conditions. Always stop the engine and do not smoke. Make sure the area is well-ventilated and free from any source of flame or sparks; this includes any appliance with a pilot light.
•
Turn the fuel tap to the OFF position.
•
Remove the carburetor.
•
Place a suitable container beneath the carburetor.
•
Remove the drain plug [A] from the bottom of the float bowl and check for water or dirt in the fuel.
If any water or dirt comes out, clean the carburetor, fuel tap and fuel tank (see this chapter).
•
Install the drain plug on the float bowl, and tighten it securely.
•
Install the carburetor.
•
Remove the carburetor.
•
Unscrew the carburetor top cap screws (KX125) or bolts
(KX250) [A].
•
Pull out the throttle valve assembly.
Carburetor
•
Remove the throttle valve assembly [A], spring [B], retainer [C] and carburetor cap from the carburetor cable lower end.
•
Disassemble the throttle valve assembly; connector [A], jet needle with circlip [B] and throttle valve [C].
•
Remove the choke knob/choke plunger assembly [A] from the carburetor.
(For KX250)
•
Remove the fuel cut valve [A] from the carburetor.
•
(For KX250)
Remove the throttle sensor mounting bolt [A].
•
Before removing the throttle sensor [B], mark [C] the carburetor body and sensor so that it can be installed later in the same position.
Carburetor
•
(For KX250)
•
Remove the throttle sensor link assembly screws [A].
Remove the link assembly [B].
KX125:
•
Remove the following parts from the carburetor body.
A. Idle Adjusting Screw
B. Nut
C. Air Screw
D. Spring
E. Slow Jet
F. Main Jet
G. Float Valve Needle
H. Float
I. Pin Screw
J. O-ring
K. Float Bowl
L. Needle Jet
M. Main Jet Holder
N. Float Plate
KX250:
•
Remove the following parts from the carburetor body.
A. Idle Adjusting Screw
B. Spring
C. Air Screw
D. Spring
E. Slow Jet
F. Main Jet
G. Float Valve Needle
H. Float
I. Pin
J. O-ring
K. Float Bowl
L. Power Jet
Carburetor
•
Clean the disassembly parts before assembling.
•
Replace the O-rings with a new one if it is deteriorated or damaged.
•
Turn in the air screw [A] fully but not tightly, and then back it out the specified number of turns. (see Specifications of this chapter)
•
For KX250, install the throttle sensor so that the marks aligns and check it position (see Electrical System chapter).
•
Tighten:
Torque - Throttle Sensor bolt: 20 N·m (0.2 kgf·m, 17 in·lb)
WARNING
Clean the carburetor in a well-ventilated area, and take care that there is no spark or flame anywhere near the working area; this includes any appliance with a pilot light. Because of the danger of highly flammable liquids, do not use gasoline or low flash
-point solvent to clean the carburetor.
•
Make sure the fuel tap is in the OFF position.
•
Remove the carburetor.
•
Drain the fuel in the carburetor.
•
Disassemble the carburetor.
CAUTION
Do not use compressed air on an assembled carburetor, the float may be deformed by the pressure.
Remove as many rubber or plastic parts from the carburetor as possible before cleaning the carburetor with a cleaning solution. This will prevent damage or deterioration of the parts. Do not use a strong carburetor cleaning solution which could attack the plastic parts; instead, use a mild high flash-point cleaning solution safe for plastic parts.
Do not use wire or any other hard instrument to clean carburetor parts, especially jets, as they may be damaged.
•
Immerse all the metal parts in a carburetor cleaning solution.
•
Rinse the parts in water.
•
After the parts are cleaned, dry them with compressed air.
•
Blow through the air and fuel passages with compressed air.
•
Assemble the carburetor, and install it on the motorcycle.
Carburetor
WARNING
Gasoline is extremely flammable and can be explosive under certain conditions. Always stop the engine and do not smoke. Make sure the area is well-ventilated and free from any source of flame or sparks; this includes any appliance with a pilot light.
•
Remove the carburetor.
•
Before disassembling the carburetor, check the fuel level
(see Fuel Level Inspection).
If the fuel level is incorrect, inspect the rest of the carburetor before correcting it.
•
Pull the carburetor cable to check that the throttle valve
[A] moves smoothly and returns by spring pressure.
If the throttle valve does not move smoothly. Replace the
• carburetor.
Disassemble the carburetor.
•
Clean the carburetor.
•
Inspect the O-rings on the float bowl, pilot screw, and throttle sensor are in good condition.
If any of the O-rings are not in good condition, replace them.
•
Inspect the tapered portion [A] of the pilot screw [B] for wear or damage.
If the pilot screw is worn or damaged on the tapered portion, it will prevent the engine from idling smoothly. Replace it.
•
Remove the float valve needle.
•
Inspect the plastic tip [A] of the float valve needle [B] for wear.
If the needle is worn as shown right [C], replace the valve needle.
•
Push the rod [D] in the valve needle, then release it.
If the rod does not come out fully by spring tension, replace the valve needle.
Push and release [E]
Carburetor
•
•
Remove the slow jet.
•
Inspect the slow jet for any damage.
If the slow jet is damaged, replace it with a new one.
•
Remove the throttle valve and jet needle.
Inspect the outside of the throttle valve for scratches and abnormal wear.
If it is badly scratched or worn, replace the throttle valve.
•
Inspect the inside of the carburetor body for these same faults.
If it is badly scratched or worn, replace the entire carburetor.
•
Inspect the jet needle for wear.
A worn jet needle should be replaced.
•
Clean the fuel and air passages with a high flash-point solvent and compressed air.
Air Cleaner
•
Remove:
Side Covers
Seat
Muffler (see Engine Top End chapter)
Bolts and Rear Fender [A]
Screws and Rear Flap [B]
•
Rear Frame Mounting Bolts [C]
Loosen the air cleaner duct clamp [D].
•
•
Remove the rear frame with the air cleaner housing [E].
•
Unscrew the air cleaner housing bolts [F].
Remove the air cleaner housing.
•
Installation is the reverse of the removal.
•
Install the air cleaner housing and tighten the bolts [A].
Torque - Air Cleaner Housing Bolts: 8.8 N·m (0.90 kgf·m, 78 ft·lb)
•
Tighten the rear frame mounting bolts [B].
Torque - Rear Frame Mounting Bolts: 34 N·m (3.5 kgf·m, 25 ft·lb)
•
Remove the seat.
•
Remove the wing bolt [A] and pull out the element [B].
•
Stuff a clean, lint-free towel into the carburetor so no dirt is allowed to enter the carburetor.
•
Wipe out the inside of the air cleaner housing with a clean damp towel.
CAUTION
Check inside of the inlet tract and carburetor for dirt. If dirt is present, clean the inlet tract and carburetor thoroughly. You may also need to replace the element and seal the housing and inlet tract.
•
When installing the element, coat the lip of the element with a thick layer of all purpose grease [A] to assure a complete seal against the air cleaner element base. Also, coat the base where the lip of the element fits.
•
Apply grease to all connections and screw holes in the air cleaner housing and inlet tract.
•
Take out the towel from the carburetor securely.
Air Cleaner
•
Install the element so that its tab [A] faces upward and fit the element projections [B] to the holes of the housing [C].
•
Refer to the Air Cleaner Element Cleaning and Inspection in the Periodic Maintenance chapter.
Fuel Tank
WARNING
Gasoline is extremely flammable and can be explosive under certain conditions. Always stop the engine and do not smoke. Make sure the area is well-ventilated and free from any source of flame or sparks; this includes any appliance with a pilot light.
•
Remove:
Radiator Shrouds
•
Seat
Turn the fuel tap to the OFF position.
•
Pull the fuel hose off the fuel tap.
•
Remove the fuel tank mounting bolt [A] and band [B].
•
•
Remove the fuel tank breather hose [C].
•
Remove the fuel tank [D].
Drain the fuel tank.
•
Check the rubber dampers [A] on the frame.
If the dampers are damaged or deteriorated, replace them.
•
Be sure the fuel hose is clamped to the fuel tap to prevent leaks.
•
Insert the fuel tank breather hose outlet end into the steering stem hole (see Appendix chapter).
•
Remove the fuel tank and drain it.
•
Remove the mounting bolts [A] and take out the fuel tap
[B].
•
•
Be sure the O-ring is in good condition to prevent leaks.
Be sure to clamp the fuel hose to the tap to prevent leaks.
Fuel Tank
•
Remove the fuel tap.
•
Check the fuel tap filter screen [A] for any breaks or deterioration.
If the fuel tap screen have any breaks or is deteriorated, it may allow dirt to reach the carburetor, causing poor running. Replace the fuel tap.
If the fuel tap leaks, or allows fuel to flow when it is at OFF position, replace the damaged O-ring [B].
•
Refer to the Fuel Tank and Tap Cleaning in the Periodic
Maintenance chapter.
Reed Valve
•
Remove the reed valve in accordance with the following procedure.
KX125
○
Remove the carburetor holder mounting bolts, and carburetor holder.
○
Remove the reed valve [A] out of the crankcase.
KX250
○
Drain the coolant.
○
Remove the carburetor and water hose [A].
○
Remove the holder mounting bolts [B], and take off the carburetor holder [C].
○
Take off the reed valve [A] out of the cylinder.
•
For KX125, install the reed valve [A] as shown.
Upward [B]
•
For KX250, install the reed valve [A] so that the ”↑” marked side [B] faces upward.
•
Tighten the carburetor holder mounting bolts.
Torque - Carburetor Holder Mounting Bolts: 8.8 N·m (0.9
kgf·m, 78 in·lb)
Read Valve Screws: 1.0 N·m (0.1 kgf·m, 9 in·lb)
Reed Valve
•
Inspect the reeds for cracks, folds, or other visible damage.
If there is any doubt as to the condition of a reed, replace the reed valve part with a new one.
If a reed becomes wavy, replace the valve part with a new one even if its warp is less than the service limit.
•
Measure the clearance between the reed [A] and holder
[B], and check the reed warp as shown.
If any one of the clearance measurements exceeds the service limit, replace the damaged valve parts with a new one.
Reed Warp
Service Limit: 0.5 mm (0.020 in.)
Table of Contents
4
Exploded View
KX125:
Exploded View
No.
Fastener
1 Water Pump Cover Bolts
2 Coolant Drain Bolt (Water Pump Cover)
3 Water Pump Impeller Bolt
4 Right Engine Cover Bolts
5 Radiator Shroud Bolts
6 Radiator Mounting Bolts
7 Radiator Screen Bolts
8 Radiator Bracket Bolts
9 Water Hose Clamp Screws
10. Radiator
11. Radiator Cap
12. Water Pump Cover
13. Impeller
14. Oil Seal (Short)
15. Oil Seal (Long)
16. Bearing
17. Water Pump Gear
18. Right Engine Cover
19. Cylinder Head
20. Cylinder
G: Apply grease.
M: Apply molybdenum disulfide grease.
8.8
8.8
8.8
8.8
N·m
8.8
8.8
6.9
8.8
1.5
Torque kgf·m
0.9
0.9
0.7
0.9
0.9
0.9
0.9
0.9
0.15
ft·lb
78 in·lb
78 in·lb
61 in·lb
78 in·lb
78 in·lb
78 in·lb
78 in·lb
78 in·lb
13 in·lb
Remarks
Exploded View
KX250:
Exploded View
No.
Fastener
1 Water Pump Cover Bolts
2 Water Pump Cover Fitting Bolts
3 Coolant Drain Bolt (Water Pump Cover)
4 Water Pump Impeller Bolt
5 Right Engine Cover Bolts
6 Coolant Drain Plug (Cylinder)
7 Water Hose Elbow Fitting Bolts
8 Radiator Shroud Bolts
9 Radiator Mounting Bolts
10 Radiator Screen Bolts
11 Radiator Bracket Bolts
12 Water Hose Clamp Screws
13. Radiator
14. Radiator Cap
15. Water Pump Cover
16. Impeller
17. Oil Seal (Short)
18. Oil Seal (Long)
19. Bearing
20. Water Pump Gear
21. Right Engine Cover
22. Cylinder Head
23. Cylinder
24. Elbow Fitting
G: Apply grease.
M: Apply molybdenum disulfide grease.
6.9
8.8
8.8
8.8
N·m
8.8
5.9
8.8
8.8
8.8
8.8
8.8
1.5
0.9
0.9
0.9
0.9
0.9
0.9
0.15
Torque kgf·m
0.9
0.6
0.9
0.7
0.9
ft·lb
78 in·lb
52 in·lb
78 in·lb
61 in·lb
78 in·lb
78 in·lb
78 in·lb
78 in·lb
78 in·lb
78 in·lb
78 in·lb
13 in·lb
Remarks
Specifications
Item
Coolant
Type
Color
Mixed Ratio
Total Amount:
KX125
KX250
Radiator
Cap Relief Pressure
Service Limit
Permanent type antifreeze for aluminum engines and radiators
Green
Soft water 50%, antifreeze 50%
0.97 L (1.02 US qt.)
1.20 L (1.27 US qt.)
93
∼
123 kPa (0.95
∼
1.25 kgf/cm², 13
∼
18 psi)
Special Tool
Bearing Driver Set:
57001-1129
Coolant
Check the coolant level each day before riding the motorcycle, and replenish coolant if the level is low. Change the coolant in accordance with the Periodic Maintenance Chart
(see Periodic Maintenance chapter).
WARNING
To avoid burns, do not remove the radiator cap or try to inspect the coolant level or change the coolant when the engine is still hot. Wait until it cools down.
•
Refer to the Coolant Inspection in the Periodic Maintenance chapter.
•
Refer to the Coolant Inspection in the Periodic Maintenance chapter.
•
Refer to the Coolant Inspection in the Periodic Maintenance chapter.
•
Refer to the Coolant Inspection in the Periodic Maintenance chapter.
•
Refer to the Coolant Inspection in the Periodic Maintenance chapter.
CAUTION
During pressure testing, do not exceed the pressure for which the system is designed to work. The maximum pressure is 123 kPa (1.25 kgf/cm², 18 psi).
•
Remove the radiator cap, and install a cooling system pressure tester [A] and adapter [B] on the radiator filler neck [C].
NOTE
○
Wet the adapter cap sealing surfaces with water or coolant to prevent pressure leaks.
•
Build up pressure in the system carefully until the pressure reaches 123 kPa (1.25 kgf/cm², 18 psi).
•
Watch the gauge for at least 6 seconds. If the pressure holds steady, the cooling system is all right.
•
Remove the pressure tester, replenish the coolant, and install the radiator cap.
If the pressure drops and no external source is found, check for internal leaks. Check the cylinder head gasket for leaks.
Coolant
Over a period of time, the cooling system accumulates rust, scale, and lime in the water jacket and radiator. When this accumulation is suspected or observed, flush the cooling system. If this accumulation is not removed, it will clog up the water passages and considerably reduce the effi-
• ciency of the cooling system.
Drain the cooling system.
•
Fill the cooling system with fresh water mixed with a flushing compound.
CAUTION
Avoid the use of a flushing compound which is harmful to the aluminum engine and radiator.
Carefully follow the instructions supplied by the manufacture of the cleaning product.
•
Warm up the engine, and run it at normal operating temperature for about ten minutes.
•
Stop the engine, and drain the cooling system after the coolant cools down.
•
•
Fill the system with fresh water.
•
Warm up the engine and drain the system after the coolant cools down.
•
Repeat the previous two steps once more.
Fill the system with a permanent type coolant, and bleed the air from the system (see Air Bleeding).
Disassembly and Assembly Precautions
•
Prior to disassembly of cooling system parts (radiator, pump, etc), wait until the coolant cools down, and then drain the coolant.
•
After assembling and filling the system with coolant, bleed any air from the system.
Water Pump
•
Drain the coolant (see Coolant Draining).
•
Loosen the water hose clamps [A], and disconnect the water hoses on the water pump cover [B].
•
Unscrew the cover bolts [C], and remove the water pump cover.
•
Replace the pump cover gasket with a new one.
•
Tighten the water pump cover bolts and clamps.
Torque - Water Pump Cover Bolts: 8.8 N·m (0.9 kgf·m, 78 in·lb)
Water Hose Clamp Screws: 1.5 N·m (0.15 kgf·m,
•
13 in·lb)
•
Fill the cooling system (see Coolant Filling).
Bleed the air from the cooling system.
•
Drain the coolant (see Coolant Draining).
•
Remove the cover bolts and take out the water pump cover from the right engine cover with the water hoses attached.
•
Remove the impeller bolt [A], and take out the impeller [B] and washer.
•
Tighten the impeller bolt.
Torque - Water Pump Impeller Bolt: 6.9 N·m (0.7 kgf·m, 61 in·lb)
Water Pump
•
Visually check the impeller [A].
If the surface is corroded, or if the blades [B] are damaged, replace the impeller.
•
Remove:
Right Engine Cover (see Right Engine Cover Removal in the Engine Right Side chapter)
•
Pull out the water pump shaft [A] toward inside of the right engine cover.
•
To prevent the oil seal lips from peeling, apply a molybdenum disulfide grease [A] to the water pump shaft [B] and insert it into the oil seals [C] from the inside of the right engine cover [D].
CAUTION
Be sure to apply a molybdenum disulfide grease to the water pump shaft when installing. If it is installed dry, the seals may wear excessively.
•
Instal the impeller and check to see that the impeller turn freely.
•
Remove:
Right Engine Cover (see Right Engine Cover Removal in the Engine Right Side chapter)
Water Pump Shaft
•
Insert a bar [A] into the water pump shaft hole from the outside of the right engine cover, and remove the ball bearing [B] by tapping [C] evenly around the bearing inner race.
Water Pump
•
Insert a bar [A] into the water pump shaft hole from the inside of the right engine cover, and remove the oil seal
[B] by tapping [C] evenly around the seal lips.
CAUTION
If the oil seal or ball bearing is removed, replace all of them with new ones at the same time
•
Be sure to replace the oil seals.
•
Apply plenty of high temperature grease to the oil seal lips
[A].
•
Press the oil seals [B] into the hole from the outside of the right engine cover.
Special Tool - Bearing Driver Set: 57001-1129 [C]
•
Set the oil seal (thick) so that dual lips side face outward and set the oil seal (thin) so that a lip faces outward as shown.
NOTE
○
Use a bearing driver larger in diameter than the oil seal, and press the oil seal into the hole until the edge of the oil seal located 0.1
∼
0.5 mm (0.0039
∼
0.0197 in.) [D] deep from the surface of the hole.
•
Press the ball bearing into the hole until the bearing is bottomed against the step [E].
Special Tool - Bearing Driver Set: 57001-1129
Radiator
•
Drain the coolant (see Coolant Draining)
•
Remove:
Radiator Shrouds
Fuel Tank (see Fuel Tank Removal in the Fuel System
• chapter)
•
Unscrew the clamps [A] and the bolts [B].
Remove the radiator screens [C].
•
Unscrew the bolts [A].
•
Remove:
Radiator Brackets [B]
Radiator [C] with the cooling hoses
○
For KX125 be sure to remove the magneto lead (harness) from left radiator.
•
Radiator installation is the reverse of removal.
•
Tighten:
Torque - Water Hose Clamp Screws: 1.5 N·m (0.15 kgf·m,
13 in·lb)
Radiator Bracket Bolts: 8.8 N·m (0.90 kgf·m, 78 in·lb)
Radiator Mounting Bolts 8.8 N·m (0.90 kgf·m, 78 in·lb)
Radiator Screen Bolts 8.8 N·m (0.90 kgf·m, 78 in·lb)
Radiator Shroud Bolts 8.8 N·m (0.90 kgf·m, 78 in·lb)
•
Route the water and breather hoses correctly.
Radiator
•
Check the radiator core.
If there are obstructions to air flow, remove them.
If the corrugated fins are deformed, carefully straighten them with the thin blade of a screwdriver [A].
CAUTION
Do not tear the radiator tubes while straightening the fins.
If the air passages of the radiator core are blocked more than 20% by unremovable obstructions or irreparably deformed fins, replace the radiator with a new one.
CAUTION
When cleaning the radiator with steam cleaner, be careful of the following to prevent radiator damage.
Keep the steam gun [C] away more than 0.5 m (1.64
ft) [B] from the radiator core. Hold the steam gun perpendicular to the core surface. Run the steam gun following the core fin direction [A].
Radiator
•
Inspect the condition of the valve spring [B], and the top and bottom valve seals [A] of the radiator cap.
If any one of them shows visible damage, replace the cap.
•
Wet the top and bottom valve seals with water or coolant to prevent pressure leaks.
•
Install the cap [A] on a cooling system pressure tester [B].
•
Watching the pressure gauge, slowly pump the pressure tester to build up the pressure. The gauge hand must remain within the relief pressure range in the table below at least 6 seconds. Continue to pump the tester until the relief valve opens, indicated by the gauge hand flicking downward. The relief valve must open within the specified range.
Radiator Cap Relief Pressure:
Standard: 93
∼
123 kPa (0.95
∼
1.25 kgf/cm², 13
∼
18 psi)
If the cap cannot hold the pressure, or if the relief pressure is too high or too low, replace the cap with a new one.
•
Inspect the radiator filler neck for signs of damage.
•
Inspect the condition of the top and bottom sealing seats
[A] in the filler neck. They must be smooth and clean for the radiator cap to function properly.
•
Refer to the Water Hoses and Connections Inspection in the Periodic Maintenance chapter.
•
Install the water hoses or breather hose being careful to follow the performed bends (see Wire, Cable and Hose
Routing in the Appendix chapter). Avoid sharp bending, kinking, flattening, or twisting.
•
Tighten the hose clamps securely.
Torque - Water Hose Clamp Screws: 1.5 N·m (0.15 kgf·m,
13 in·lb)
Table of Contents
5
Exploded View
KX125:
Exploded View
No.
Fastener
1 Main Valve Cover Bolts
2 Cylinder Head Nuts
3 Spark Plug
Engine Mounting Bracket Nut (Engine Side 10 mm)
4 (KX125-M1)
(KX125-M2
∼
)
5 Engine Mounting Bracket Nuts (Frame Side 8 mm)
KIPS Cover Bolts
6 (KX125-M1)
(KX125-M2
∼
)
7 Cylinder Nuts
8 Governor Shaft Lever Mounting Bolt
9 Main Shaft Stopper Pin Plug
10 Main Lever Mounting Allen Bolt
11 Exhaust Valve Retaining Bolts
12 Muffler Pipe Mounting Bolts
13 Inner Pipe Mounting Bolts
14 Muffler Damper Mounting Bolts
15 Expansion Chamber Mounting Bolt
16 Muffler Mounting Bolts
17. Main Valve Cover
18. Cylinder Head
19. Engine Mounting Brackets
20. KIPS Cover
21. Piston Ring
22. Piston
23. “R” Mark
24. “Alphabet” Mark
25. Piston Pin
26. Cylinder
27. Main Shaft
28. Main Lever
29. Spring
30. Exhaust Valve Retaining Plate
31. Governor Shaft Lever
32. Exhaust Valve Right (Identification Slot)
33. Exhaust Valve Left
34a. Expansion Chamber (KX125-M1 model)
34b. Expansion Chamber (KX125-M2 model
∼
)
35. Rubber Seals
36. Muffler Body
G: Apply grease.
L: Apply a non-permanent locking agent.
M: Apply molybdenum disulfide grease.
O: Apply 2-stroke engine oil.
SS: Apply silicone sealant.
R: Replacement Parts
N·m
5.9
25
27
Torque kgf·m ft·lb
0.6
52 in·lb
2.5
2.8
18
20
Remarks
44
49
29
4.9
8.8
25
6.9
0.8
3.9
5.9
8.8
8.8
8.8
12
8.8
4.5
5.0
3.0
0.5
0.4
0.9
33
36
22
43 in·lb
0.9
78 in·lb
2.5
18
0.7
61 in·lb
0.08
7 in·lb
35 in·lb
0.6
52 in·lb
0.9
78 in·lb
0.9
78 in·lb
0.9
78 in·lb
1.2
8.7
78 in·lb
L
L
L
Exploded View
KX250:
Exploded View
No.
20. Cylinder Head
22. Governor Shaft Lever
23. KIPS Cover
24. Operating Rod
25. Main Valve Cover
26. Main Lever
27. Spring
(KX250-M1 model)
29. Main Valve Rod Cover
30. Main Valve Rod
31. Main Shaft
32. Cylinder Left Cover
33. Cylinder
34. Exhaust Valve (Left)
35. Exhaust Valve (Right)
36. Guide
37. O-ring
Fastener
1 Cylinder Head Nuts
2 Spark Plug
3 Main Valve Cover Bolts
4 Main Valve Retaining Bolts
5 Main Valve Rod Cover Screw
6 Main Lever Mounting Allen Bolt
7 Operating Rod Retaining Screw
8 Coolant Drain Plug (Cylinder)
9 Cylinder Nuts
10 Operating Rod Left Side Plug
11 Cylinder Left Cover Bolts
12 KIPS Cover Bolts
13 Engine Mounting Bracket Nuts (Frame Side 8 mm)
Engine Mounting Bracket Nuts (Engine Side 10 mm)
14 (KX250-M1)
(KX250-M2
∼
)
15 Muffler Pipe Mounting Bolts
16 Inner Pipe Mounting Bolts
17 Muffler Damper Mounting Bolts
18 Expansion Chamber Mounting Bolt
19 Muffler Mounting Bolts
21. Engine Mounting Brackets
28a. Main Exhaust Valve Assembly
28b. Main Exhaust Valve Assembly
(KX250-M2 model
∼
)
N·m
25
27
5.9
5.9
34
22
5.9
2.9
29
5.9
3.9
5.4
8.8
Torque kgf·m
2.5
ft·lb
18
2.8
20
0.6
52 in·lb
0.6
52 in·lb
0.6
0.4
0.55
0.9
3.5
2.2
0.6
0.3
3.0
52 in·lb
35 in·lb
48 in·lb
78 in·lb
25
16
52 in·lb
26 in·lb
22
Remarks
L
44
49
8.8
8.8
8.8
12
8.8
4.5
5.0
0.9
0.9
0.9
1.2
0.9
33
36
78 in·lb
78 in·lb
78 in·lb
8.7
78 in·lb
L
L
38. Idle Gear
39. Guide
40. Piston Ring
41. Piston
42. “IN” Mark
43. Piston Pin
44. Reed Valve
45a. Expansion Chamber
(KX250-M1 model)
45b. Expansion Chamber
(KX250-M2 model
∼
)
46. Rubber Seals
47. Gasket
48. Muffler Body
49. Vent Hose (KX250-M2 model
∼
)
G: Apply grease.
L: Apply a non-permanent locking agent.
M: Apply molybdenum disulfide grease.
O: Apply 2-stroke engine oil.
SS: Apply silicone sealant.
R: Replacement Parts
Specifications
KX125:
Item
Cylinder Head
Standard Service Limit
Cylinder Compression
Cylinder Head Warp
(Usable range)
890
∼
1 370 kPa
(9.1
∼
14.0 kgf/cm², 129
∼
199 psi)
– – –
– – –
0.03 mm (0.0012 in.)
Cylinder, Piston
Cylinder Inside Diameter (15 mm (0.59 in.) below of the cylinder head)
54.010
∼
54.025 mm (2.1264
∼
2.1270 in.) 54.10 mm (2.130 in.)
Piston Diameter
Piston/Cylinder Clearance
53.955
∼
53.970 mm (2.1242
∼
2.1248 in.) 53.81 mm (2.118 in.)
0.040
∼
0.070 mm (0.0016
∼
0.0028 in.) – – –
Piston Ring/Groove Clearance 0.015
∼
0.050 mm (0.0006
∼
0.0020 in.)
Piston Ring Groove Width 1.01
∼
1.03 mm (0.0398
∼
0.0406 in.)
0.15 mm (0.006 in.)
1.11 mm (0.044 in.)
Piston Ring Thickness
Piston Ring End Gap
Piston Pin Diameter
Piston Pin Hole Diameter
Small End Inside Diameter
0.980
∼
0.995 mm (0.0386
∼
0.0392 in.)
0.35
∼
0.55 mm (0.0138
∼
0.0217 in.)
0.91 mm (0.036 in.)
0.85 mm (0.033 in.)
14.995
∼
15.000 mm (0.5904
∼
0.5906 in.) 14.96 mm (0.589 in.)
15.001
∼
15.011 mm (0.5906
∼
0.5910 in.) 15.08 mm (0.594 in.)
19.003
∼
19.014 mm (0.7481
∼
0.7486 in.) 19.05 mm (0.750 in.)
KX250:
Item Standard Service Limit
Cylinder Head
Cylinder Compression
Cylinder Head Warp
(Usable range)
825
∼
1 275 kPa
(8.4
∼
13.0 kgf/cm², 119
∼
185 psi)
– – –
– – –
0.03 mm (0.0012 in.)
Cylinder, Piston
Cylinder Inside Diameter 66.400
∼
66.415 mm (2.6142
∼
2.6148 in.) 66.46 mm (2.617 in.)
(30 mm (1.18 in.) below of the cylinder head)
Piston Diameter
Piston/Cylinder Clearance
Piston Pin Hole Diameter
Small End Inside Diameter
66.336
∼
66.351 mm (2.6116
∼
2.6122 in.) 66.19 mm (2.6059 in.)
0.049
∼
0.079 mm (0.0019
∼
0.0031 in.) – – –
Piston Ring/Groove Clearance 0.025
∼
0.06 mm (0.00098
∼
0.00236 in.) 0.16 mm (0.006 in.)
Piston Ring Groove Width 1.01
∼
1.03 mm (0.0398
∼
0.0406 in.) 1.11 mm (0.044 In.)
Piston Ring Thickness
Piston Ring End Gap
Piston Pin Diameter
0.970
∼
0.985 mm (0.0382
∼
0.0388 in.) 0.90 mm (0.035 in.)
0.25
∼
0.45 mm (0.0098
∼
0.0177 in.) 0.75 mm (0.030 in.)
17.995
∼
18.000 mm (0.7085
∼
0.7087 in.) 17.96 mm (0.707 in.)
18.001
∼
18.011 mm (0.7087
∼
0.7091 in.) 18.08 mm (0.712 in.)
22.003
∼
22.012 mm (0.8663
∼
0.8666 in.) 22.05 mm (0.868 in.)
Special Tools
Compression Gauge, 20 kgf/cm²:
57001-221
Compression Gauge Adapter, M14 × 1.25:
57001-1159
Piston Pin Puller Assembly:
57001-910
Cylinder Head
•
Start the engine.
•
Thoroughly warm up the engine so that the engine oil between the piston and cylinder wall will help seal compres-
• sion as it does during normal running.
Stop the engine.
•
Remove the fuel tank (see Fuel System chapter).
•
Remove the spark plug, and screw a compression gauge firmly into the spark plug hole.
Special Tools - Compression Gauge, 20 kgf/cm²: 57001-221
[A]
Compression Gauge Adapter, M14 × 1.25:
57001-1159 [B]
•
With the throttle fully open, turn the engine over sharply with the kickstarter several times until the compression gauge stops riding; the compression is the highest reading obtainable.
Cylinder Compression
Usable Range:
KX125 890
∼
1 370 kPa (9.1
∼
14.0 kgf/cm², 129
∼
199 psi)
KX250 825
∼
1 275 kPa (8.4
∼
13.0 kgf/cm², 119
∼
185 psi)
If cylinder compression is higher than the usable range, check the following:
1. Carbon build up on the piston head and cylinder head clean off any carbon on the piston head.
2. Cylinder head gasket, cylinder base gasket - use only the proper gaskets for the cylinder head and base. The use of gasket of the incorrect thickness will change the compression.
If cylinder compression is lower than the usable range, check the following:
1. Piston/cylinder clearance, piston seizure.
2. Gas leakage around the cylinder head - replace the damaged gasket and check the cylinder head for warping.
3. Piston ring, piston ring groove.
•
Drain the coolant (see Cooling System chapter).
•
Remove:
Radiator Shrouds
Seat
Side Covers
Fuel Tank (see Fuel Tank Removal in the Fuel System chapter)
Muffler (see this chapter)
Radiators (see Radiator Removal in the Cooling System chapter)
Water Hose [A]
Spark Plug [B]
Bolts & Nuts [C]
Engine Mounting Brackets [D]
Cylinder Head
•
Remove the cylinder head nuts [A], and take off the cylinder head [B] and the O-rings (KX125) or the gasket
(KX250).
•
Replace the O-rings or the head gasket with a new one.
•
Scrape out any carbon and clean the head with a high flash-point solvent.
•
Check for a crust of minerals and rust in the head water jacket, and remove them if necessary.
•
For KX125, install new O-rings to the grooves of the cylinder securely.
•
For KX250, install a new cylinder head gasket with the EX marked side [A] forward.
•
Tighten the head nuts diagonally.
Torque - Cylinder Head Nuts: 25 N·m (2.5 kgf·m, 18 ft·lb)
•
Tighten the engine mounting bracket nuts.
Torque - Cylinder Head Nuts: 25 N·m (2.5 kgf·m, 18 ft·lb)
Engine Mounting Bracket Nuts:
10 mm: 44 N·m (4.5 kgf·m, 33 ft·lb) (KX125/250
-M1)
49 N·m (5.0 kgf·m, 36 ft·lb) (KX125/250
-M2
∼
)
8 mm: 29 N·m (3.0 kgf·m, 22 ft·lb)
•
Tighten the spark plug.
Torque - Spark Plug: 27 N·m (2.8 kgf·m, 20 ft·lb)
•
Refer to the Cylinder Head Warp Inspection in the Periodic Maintenance chapter.
Cylinder
•
Drain the coolant (see Coolant Inspection in the Periodic
Maintenance chapter).
○
For KX250: be sure to remove the cylinder drain plug.
•
•
Remove the cylinder head (see this chapter).
•
Remove the water hoses.
Remove the KIPS cover [A] at the cylinder.
•
Remove the governor shaft lever in accordance with the following procedure .
KX125
○
Remove the bolt [A] and pull out the governor shaft lever
[B] from the main shaft.
KX250
○
Loosen the clamps, and pull the carburetor out of the holder and the air cleaner duct.
○
Remove the E-clip [A] from the operating rod.
○
Put a 9 mm (0.35 in.) spanner wrench [A] on the governor shaft lever upper end.
○
Turn the governor shaft lever [B] counterclockwise with the wrench, and take off the operating rod collar [C] by pushing the operating rod into the cylinder.
○
Before pulling the governor shaft lever [A] free, turn the remaining E-clip [B] to a suitable position as shown in the figure to prevent the governor shaft lever boss [C] and the
E-clip from hitting.
Cylinder
•
For KX250, remove the magneto lead and the clutch cable from clamp.
•
Remove the cylinder nuts [A].
•
Lift off the cylinder, and remove the cylinder base gasket.
If necessary, tap lightly around the base of the cylinder with a plastic mallet [A], taking care not to damage the cylinder.
•
Remove the exhaust valves from the cylinder (see Exhaust Valve Removal).
•
Scrape any carbon out of the exhaust port.
•
Check on a crust of minerals and rust in the cylinder water jacket, and remove them if necessary.
•
Replace the cylinder base gasket with a new one.
•
Apply engine oil to the piston surface, piston rings and cylinder bore.
•
Check to see that the pin [A] in each piston ring groove is between the ends of the piston ring, and fit the base of the cylinder over each ring, pressing in on opposite sides of the ring as necessary. Be certain that the rings do not slip out of position.
•
Tighten the cylinder nuts diagonally.
Torque - Cylinder Nuts:
KX125: 25 N·m (2.5 kgf·m, 18 ft·lb)
KX250: 34 N·m (3.5 kgf·m, 25 ft·lb)
KX125
•
Using the 14 mm (0.56 in.) spanner wrench [A], turn the governor shaft counterclockwise.
•
Install the governor shaft lever [B] to the main shaft and tighten the bolt [C].
Torque - Governor Shaft Lever Mounting Bolt: 6.9 N·m (0.7
•
kgf·m, 61 in·lb)
Install the KIPS cover.
•
Tighten:
Torque - KIPS Cover Bolts:
KX125-M1: 4.9 N·m (0.5 kgf·m, 43 in·lb)
KX125-M2
∼
: 8.8 N·m (0.9 kgf·m, 78 in·lb)
Cylinder
KX250
•
Install the governor shaft lever and operating rod collar in accordance with the following procedure.
○
Put a 9 mm (0.35 in.) spanner [A] wrench on the governor shaft lever upper end.
○
Turn the governor shaft lever counterclockwise with the wrench and fit the groove of the operating rod collar [B] to the boss of the governor shaft lever, and install the collar on the operating rod while holding the governor shaft lever clockwise.
•
After installing the collar, install the E-clip [A] on the operating rod [B].
•
Install the KIPS cover.
•
Tighten:
Torque - KIPS Cover Bolts: 2.9 N·m (0.3 kgf·m, 26 in·lb)
•
Remove the cylinder.
•
Stuff a clean cloth into the crankcase opening around the connecting rod so that no parts will fall into the crankcase.
•
Remove one of the piston pin snap rings with needle nose pliers.
•
Remove the piston by pushing the piston pin out the side from which the snap ring was removed. Use a piston pin puller assembly [A], if the pin is tight.
Special Tool - Piston Pin Puller Assembly: 57001-910
•
Remove the piston ring(s).
○
Carefully spread the ring [A] opening with your thumbs and then push up on the opposite side of the ring to remove it.
•
Stuff a clean cloth into the crankcase opening around the connecting rod so that no parts will fall into the crankcase.
•
Scrape off any carbon of the piston, then lightly polish the piston with fine emery cloth.
•
Clean carbon and dirt out of the piston ring groove using a suitable tool.
CAUTION
Carbon particles can be very abrasive to piston ring. Don’t allow such particles to fall onto the cylinder walls.
Cylinder
•
When installing the piston ring on the piston, note the following:
○
For KX250, the top [A] and second [B] rings are identical.
○
First fit one end of the piston ring against the pin in the ring groove, spread the ring opening with the other hand and then slip the ring into the groove.
○
For KX125, the piston ring have a “R” mark [A] on it upper surface.
○
Install the ring so that the pin [A] in the piston ring groove is between the ends of the piston ring.
•
Apply 2-stroke engine oil to the connecting rod needle bearing and the piston pin.
•
For KX125, install the piston so that the “Alphabet” marked side [A] faces the front side (Exhaust side) of the engine.
•
For KX250, install the piston so that the “IN” marked side
[A] faces the back side of the engine.
•
When installing a piston pin snap ring [A], compress it only enough to install it and no more.
CAUTION
Do not reuse snap rings, as removal weakens and deforms them. They could fall out and score the cylinder wall.
•
Fit a new piston pin snap ring into the side of the piston so that the ring opening [B] does not coincide with the notch
[C] in the edge of the piston pin hole.
•
Refer to the Cylinder Wear Inspection in the Periodic
Maintenance chapter.
Cylinder
•
Refer to the Piston Diameter Measurement in the Periodic
Maintenance chapter.
•
Refer to the Piston/Cylinder Clearance Inspection in the
Periodic Maintenance chapter.
•
Refer to the Piston Ring, Piston Ring Groove Inspection in the Periodic Maintenance chapter.
•
Refer to the Piston Ring End Gap Inspection in the Periodic Maintenance chapter.
•
Refer to the Piston, Piston Pin, Connecting Rod Wear
Inspection in the Periodic Maintenance chapter.
Exhaust Valve (KIPS)
•
Drain the coolant.
•
Remove:
Radiator (see Radiator Removal in the Cooling System chapter)
Muffler (see Muffler Removal)
KIPS Cover (see Right Engine Cover Removal in the
Engine Right Side chapter)
Bolt [A]
Governor Shaft Lever [B]
•
Remove:
Cylinder (see Cylinder Removal)
Main Valve Cover Bolts [A]
Main Valve Cover [B]
Stopper Pin Screw [A] and Stopper Pin [B]
Allen Bolt [C]
•
Pull out the main exhaust valve shaft [A] and remove the main lever [B] with spring [C].
•
Remove the exhaust valve retaining bolts [A].
•
Pull out the exhaust valves [B].
Exhaust Valve (KIPS)
•
Remove:
Carburetor (see Carburetor Removal in the Fuel System chapter)
•
Cylinder Head (see Cylinder Head Removal)
Remove the KIPS cover at the cylinder
•
Remove the E-clip [A] and operating rod collar [B] from the operating rod.
•
Remove the cylinder (see Cylinder Removal).
•
Turn the cylinder up side down.
•
Remove the plug [A] and the gasket [B] at the left side of the cylinder.
•
Pull out the operating rod [A] as far as it goes.
•
Remove the operating rod retaining screw [B].
•
Remove the idle gear [A].
•
Lift up the exhaust valves [B], and remove the valve guides [C].
•
Lift up the exhaust valves, and pull out the operating rod
[D]. Then take out the exhaust valves.
•
Remove the main valve cover [A], main valve rod cover
[B] and cylinder left cover [C] from the cylinder.
Exhaust Valve (KIPS)
•
Unscrew the Allen bolt [A] from the main lever [B].
•
Position the main exhaust valve full open, and pull out the main shaft [C].
•
Set the main exhaust valve full closed position, and remove the main lever with spring [D].
•
Pull out the main valve rod [E] from the cylinder.
•
Unscrew the two main valve retaining bolts [A] and take out the main exhaust valve assembly [B] from the cylinder.
•
Scrape out any carbon and clean the valves with a high flash-point solvent.
•
Check the following for signs of damage:
Exhaust Valves
Oil Seal
Gaskets
•
If necessary, replace them with new ones.
Apply a 2-stroke engine oil to the operation parts.
•
Apply a high temperature grease to the oil seal lip.
•
Insert the exhaust valves [A] so that their spherical parts
[B] shall direct to downward.
NOTE
○
There are left and right sides for the exhaust valves.
○
Right exhaust valve has a identification slot [C] so that it shall be installed upward.
•
Install the retaining plate [D] and tighten exhaust valve retaining bolts [E].
Torque - Exhaust Valve Retaining Bolts: 5.9 N·m (0.6 kgf·m,
52 in·lb)
•
Check that the exhaust valves slide smoothly.
Exhaust Valve (KIPS)
•
Fit the spring [A] to the main lever [B].
•
Insert the main shaft [A] in the hole of the cylinder and through the holes in the main lever [B] with spring [C].
•
Install the stopper pin [A].
•
Tighten:
Torque - Main Shaft Stopper Pin Plug: 0.8 N·m (0.08 kgf·m,
•
7 in·lb)
Apply a non-permanent locking agent to the Allen bolt [B].
•
Fix the main lever to the main shaft with the Allen bolt.
•
Tighten:
Torque - Main Lever Mounting Allen Bolt: 3.9 N·m (0.4
•
kgf·m, 35 in·lb)
Install the main valve cover.
•
Tighten:
Torque - Main Valve Cover Bolts: 5.9 N·m (0.6 kgf·m, 52 in·lb)
NOTE
○
When main shaft [A] turns clockwise and with the exhaust valves [B] fully opened position, check the end of exhaust valves and the exhaust ports [C] are aligned with.
Exhaust Valve (KIPS)
•
Install the cylinder (see Cylinder Installation).
•
Tighten:
Torque - Cylinder Nuts: 25 N·m (2.5 kgf·m, 18 ft·lb)
•
Using the 14 mm (0.56 in.) spanner wrench [A], install the governor shaft lever [B] as shown.
•
Tighten:
Torque - Governor Shaft Lever Mounting Bolt [C]: 6.9 N·m
•
(0.7 kgf·m, 61 in·lb)
Install the KIPS cover.
•
Tighten:
Torque - KIPS Cover Bolts:
KX125-M1: 4.9 N·m (0.5 kgf·m, 43 in·lb)
KX125-M2
∼
: 8.8 N·m (0.9 kgf·m, 78 in·lb)
•
Install the removal parts.
•
Remove any carbon and clean the valves with a high flash
-point solvent.
•
Check the following for signs of damage:
Exhaust Valves
Valve Operating Rod
Oil Seal on Rod Seal Plug
O-rings
Gaskets
If necessary, replace damaged or worn items with new ones.
•
Check the gasket on the left plug for signs of damage.
If necessary, replace it with new one.
•
Install the operating rod left side plug on the cylinder.
•
Tighten:
Torque - Operating Rod Left Side Plug: 22 N·m (2.2 kgf·m,
16 ft·lb)
•
Apply a 2-stroke engine oil to the following:
Valve Guides (inside)
Valve Operating Rod Journals
Valve Operating Rod Rack
Main Exhaust Valve Parts
•
Apply a high temperature grease to the oil seal lip on the operating rod.
•
Set up the main exhaust valve assembly as shown.
Slide Valve [A]
Valve Holder [B]
•
Check the slide valve move smoothly.
Exhaust Valve (KIPS)
•
For KX250-M2 model
∼
; note the following.
○
Apply a 2-stroke engine oil to the main exhaust valve [A].
•
Insert the main exhaust valve assembly [A] into the cylinder [B].
•
Install the main valve retaining bolts [C] securely and tighten them.
Torque - Main Valve Retaining Bolts: 5.9 N·m (0.6 kgf·m, 52 in·lb)
•
Check the main exhaust valve assembly slide smoothly.
•
Fit the spring [A] to the main lever [B].
•
Install the main lever [A] with spring to the slide valve pin
[B].
•
Install the main valve rod [C] in the cylinder so that the grooved side [D] faces outward and the gear teeth face down.
•
Insert the main shaft [A] into the hole of the left upper end at the cylinder and through the hole in the main lever [B] and spring [C]. Then put the main shaft into the cylinder hole.
Exhaust Valve (KIPS)
•
Align the punch mark [A] on the main shaft gear with the groove [B] on the main valve rod.
•
Turn the cylinder upside down.
•
Push [A] the main valve rod in until it is fully seated into the cylinder.
•
Insert the sub exhaust valves partially into the cylinder so that the operating rod can pass underneath the gears.
The right sub exhaust valve [A] is smaller than the left sub exhaust valve.
•
Insert the operating rod until it is fully seated against the plug on the opposite side of the cylinder, and push the oil seal assembly into the cylinder.
•
Align the punch mark [B] (marked with red paint) on the exhaust valve rods [A] with the grooves [C] in the operating rod.
NOTE
○
The marked tooth [A] is identified by its shape also.
[B] Punch Mark (Red Panjab)
Exhaust Valve (KIPS)
•
•
Insert the idle gear.
Apply high temperature grease to the O-ring.
•
Mount the valve guides [B, D] on the sub exhaust valves
[A] and idle gear [C].
•
Apply a non-permanent locking agent to the Allen bolt.
•
Fix the main lever [A] to the main shaft [B] with the Allen bolt [C].
•
Tighten:
Torque - Main Lever Mounting Allen Bolt: 3.9 N·m (0.4
kgf·m, 35 in·lb)
•
Check that the main exhaust valve assembly slide smoothly.
NOTE
○
When tighten the main lever mounting Allen bolt [A], main exhaust valve assembly [B] should be in fully closed position as shown.
•
For KX250-M2 model
∼
; as shown in the figure.
•
There are three checks to ensure the sub exhaust valves are in the correct position:
○
With the sub exhaust valves in the fully closed position the hole leading to the left side KIPS chamber is only partially open [A].
Exhaust Valve (KIPS)
○
The distance from the top of the operating rod collar to the cylinder should be 14.5
∼
15.5 mm (0.57
∼
0.61 in.) [A].
○
In the fully open position with the main valve rod flush with the cylinder [A], the sub exhaust valves will be aligned [B] with the sub exhaust ports.
•
•
Check that the sub exhaust valves operate smoothly.
Install the operating rod retaining screw securely.
•
Tighten:
Torque - Operating Rod Retaining Screw: 5.4 N·m (0.55
kgf·m, 48 in·lb)
•
Install the main valve cover, main valve rod cover and cylinder left cover on the cylinder.
•
Tighten:
Torque - Main Valve Cover Bolts: 5.9 N·m (0.6 kgf·m, 52 in·lb)
Main Valve Rod Cover Screw: 5.9 N·m (0.6 kgf·m,
52 in·lb)
•
Install the removed parts.
Muffler (Expansion Chamber, Muffler Body)
•
Remove:
Right Radiator Shroud
Right Side Cover
•
Remove the mounting bolts [A] and pull the muffler body
[B] off toward the rear.
•
Remove the exhaust pipe holding springs [A].
•
Remove the muffler damper mounting bolts [A], and pull off the expansion chamber to the front ward.
•
Remove the O-rings from the expansion chamber.
○
For KX250: be sure to remove exhaust gasket.
•
For KX125/250-M2 model
∼
; as shown in the figure.
•
Scrape any carbon out of the expansion chamber.
•
Check the exhaust O-rings for signs of damage.
If necessary, replace them with new ones.
•
Tighten:
Torque - Muffler Damper Mounting Bolts: 8.8 N·m (0.9
kgf·m, 78 in·lb)
Muffler Mounting Bolts: 8.8 N·m (0.9 kgf·m, 78 in·lb)
•
Refer to the Muffler Baffle Change in the Periodic Maintenance chapter.
Table of Contents
6
Exploded View
KX125:
Exploded View
No.
Fastener
1 Clutch Hub Nut
2 Clutch Spring Bolts
3 Clutch Cover Bolts
4 Governor Shaft Lever Positioning Plug
5 Oil Filler Cap
6 Right Engine Cover Bolts
7 Governor Shaft Lever Mounting Bolt
8 Exhaust Valve Advancer Lever Mounting Allen Bolt 3.9
9 Primary Gear Nut 59
10 Gear Set Lever Nut
11 Ratchet Plate Mounting Bolts
8.8
8.8
12 Kick Ratchet Guide Bolt
13 Kick Pedal Bolt
14 Shift Pedal Bolt
8.8
12
9.8
0.6
1.5
8.8
6.9
N·m
98
8.8
8.8
15. Clutch Lever
16. Clutch Cable
17. Clutch Cover
18. Right Engine Cover
19. Governor Shaft Lever
20. Primary Gear
21. Exhaust Advancer Assembly
22. Gear Set Lever
23. Ratchet Assembly
24. Shift Shaft
25. Kickstarter Idle Gear
26. Ratchet Gear
27. Kick Gear
28. Kick Shaft
29. Clutch Hub
30. Release Lever Shaft
31. Push Rod
32. Steel Plate
33. Friction Plate
34. Sleeve
35. Clutch Housing
36. Push Rod Holder
37. Clutch Pressure Plate
EO: Apply engine oil.
G: Apply high temperature grease.
L: Apply a non-permanent locking agent to the threads.
M: Apply molybdenum disulfide grease
O: Apply oil.
Si: Apply silicone grease.
A: KX125-M1
∼
M3 Model
B: KX125M6F Model
∼
0.9
0.9
0.9
1.2
1.0
0.9
0.7
0.4
6.0
Torque kgf·m
10.0
0.9
0.9
0.06
0.15
ft·lb
72
78 in·lb
78 in·lb
5 in·lb
13 in·lb
78 in·lb
61 in·lb
35 in·lb
43
78 in·lb
78 in·lb
78 in·lb
104 in·lb
87 in·lb
Remarks
L
Exploded View
KX250:
Exploded View
No.
Fastener
1 Clutch Cover Bolts
2 Right Engine Cover Bolts
3 Oil Filler Cap
4 Governor Shaft Lever Positioning Plug 0.6
5 Exhaust Valve Advancer Lever Mounting Allen Bolt 3.9
6 Gear Set Lever Nut
7 Ratchet Plate Mounting Bolts
8.8
8.8
N·m
8.8
8.8
1.5
8 External Shift Mechanism Return Spring Pin
9 Clutch Hub Nut
10 Clutch Spring Bolts
11 Kick Ratchet Guide Bolt
12 Kick Pedal Bolt
13 Shift Pedal Bolt
42
98
8.8
8.8
25
9.8
14. Clutch Lever
15. Clutch Cable
16. Clutch Cover
17. Right Engine Cover
18. Governor Shaft Lever
19. Exhaust Advancer Assembly
20. Water Pump Driver Gear
21. Primary Gear
22. Gear Set Lever
23. Ratchet Assembly
24. Shift Shaft
25. Ratchet Gear
26. Kickstarter Idle Gear
27. Kick Gear
28. Kick Shaft
29. Clutch Hub
30. Steel Plate
31. Friction Plate
32. Push Rod Holder
33. Clutch Pressure Plate
34. Clutch Housing
35. Sleeve
36. Push Rod
37. Release Lever Shaft
EO: Apply engine oil.
G: Apply high temperature grease.
L: Apply a non-permanent locking agent to the threads.
M: Apply molybdenum disulfide grease.
O: Apply oil.
Si: Apply silicone grease.
Torque kgf·m
0.9
ft·lb
78 in·lb
0.9
78 in·lb
0.15
13 in·lb
0.06
0.4
0.9
0.9
5 in·lb
35 in·lb
78 in·lb
78 in·lb
4.3
10.0
0.9
0.9
2.5
1.0
31
72
78 in·lb
78 in·lb
18
87 in·lb
Remarks
L
L
Specifications
Item
Clutch
Lever Free Play
Friction Plate Thickness
KX125
KX250
Steel Plate Thickness:
KX125
KX250
Friction Plate Warp
Steel Plate Warp
Clutch Spring Free Length:
KX125
KX250
Friction Plate/Clutch Housing
Clearance
KX125
KX250
Standard
2
∼
3 mm (0.08
∼
0.12 in.)
2.72
∼
2.88 mm (0.107
∼
0.113 in.)
2.92
∼
3.08 mm (0.115
∼
0.121 in.)
1.5
∼
1.7 mm (0.059
∼
0.067 in.)
1.46
∼
1.74 mm (0.057
∼
0.069 in.)
0.15 mm (0.006 in.) or less
0.2 mm (0.008 in.) or less
46.8 mm (1.843 in.)
35.0 mm (1.378 in.)
Service Limit
– – –
2.6 mm (0.102 in.)
2.8 mm (0.110 in.)
1.4 mm (0.055 in.)
1.36 mm (0.054 in.)
0.3 mm (0.119 in.)
0.3 mm (0.119 in.)
44.9 mm (1.768 in.)
33.6 mm (1.323 in.)
0.04
∼
0.55 mm (0.0016
∼
0.0217 in.) 0.9 mm (0.0354 in.)
0.15
∼
0.45 mm (0.0059
∼
0.0177 in.) 0.8 mm (0.0315 in.)
Special Tools
Outside Circlip Pliers:
57001-144
Clutch Holder:
57001-1243
Flywheel Holder:
57001-1313
Flywheel & Pulley Holder:
57001-1605
Clutch Cable
Due to friction plate wear and clutch cable stretch over a long period of use, the clutch must be adjusted in accordance with the Periodic Maintenance Chart.
WARNING
To avoid a serious burn, never touch the hot engine or exhaust chamber during clutch adjustment.
•
Refer to the Clutch Inspection in the Periodic Maintenance chapter.
•
Refer to the Clutch Inspection in the Periodic Maintenance chapter.
•
Slide the dust cover out of place.
•
Loosen the locknut at the upper of the cable, and turn the adjusting nut to give the cable plenty of play.
•
Loosen the knurled locknut [A] at the clutch lever, and screw in the adjuster [B].
•
Line up the slots [C] in the clutch lever, knurled locknut, and adjuster, and then free the cable from the clutch lever.
○
For KX125, remove the magneto cover (see Release
Shaft Removal).
•
Free the clutch inner cable tip from the clutch release lever.
CAUTION
Do not remove the clutch release shaft unless it is absolutely necessary. If removed, release shaft oil seal must be replaced with a new one.
•
Pull the clutch cable out of the frame.
•
Run the clutch cable according to the Cable, Wire and,
Hose Routing section in the Appendix chapter.
•
Adjust the clutch cable (see Free Play Adjustment).
•
Lubricate the clutch cable using the pressure cable luber in accordance with the Periodic Maintenance Chart.
•
With the cable disconnected at both ends, the cable should move freely within the cable housing (see General Lubrication in the Periodic Maintenance chapter).
Clutch Cover
•
Drain the engine oil (see Transmission Oil Change in the
Periodic Maintenance chapter).
•
Remove the brake pedal (see Brake Pedal Removal in the Brake chapter).
•
Unbolt the clutch cover bolts [A], and take off the clutch cover [B].
•
There are two knock pins of the mating surfaces of right engine cover and clutch cover.
•
Replace the clutch cover gasket with a new one.
•
Tighten the clutch cover bolts.
Torque - Clutch Cover Bolts: 8.8 N·m (0.9 kgf·m, 78 in·lb)
•
Install the brake pedal (see Brake Pedal Installation in the
Brake chapter)
Right Engine Cover
•
Removal:
Engine Oil (drain) (see Transmission Oil Change in the
Periodic Maintenance chapter)
Coolant (drain) (see Coolant Inspection in the Periodic
Maintenance chapter)
Water Hose Lower End
Kick Pedal
Brake Pedal
Muffler
•
Unscrew the KIPS cover bolt [A] and remove the KIPS cover [B] from the right side of the cylinder.
•
Remove the governor shaft lever in accordance with the following procedure.
KX125
○
Remove the bolt [A] and pull out the governor shaft lever
[B] from the main shaft.
KX250
○
Remove the E-clip [A] from the operating rod.
○
Put a 9 mm (0.35 in.) spanner wrench [A] on the governor shaft lever upper end.
○
Turn the governor shaft lever [B] counterclockwise with the wrench, and take off the operating rod collar [C] by pushing the operating rod into the cylinder.
Right Engine Cover
○
Before pulling the governor shaft lever [A] free, turn the remaining E-clip [B] to a suitable position as shown in the figure to prevent the governor shaft lever boss [C] and the
E-clip from hitting.
○
Remove the cover bolts [A] and take off the right engine cover [B] and gasket.
•
There are two knock pins of the mating surfaces of the crankcase and right engine cover.
•
In case the exhaust advancer assembly has been removed, install it and turn the gear so as to level the gear drive pin [A].
CAUTION
If the gear drive pin is not positioned level, it may fall out when installing the right engine cover.
•
Apply a high-temperature grease to the kick pedal oil seal lips and kick shaft spline.
•
Tighten the right engine cover bolts and kick shaft mounting bolt.
Torque - Right Engine Cover Bolts: 8.8 N·m (0.9 kgf·m, 78 in·lb)
Kick Pedal Bolt:
KX125: 12 N·m (1.2 kgf·m, 104 in·lb)
KX250: 25 N·m (2.5 kgf·m, 18 ft·lb)
KX125
•
Using the 14 mm (0.56 in.) spanner wrench [A], install the governor shaft lever [B] as shown.
•
Tighten:
Torque - Governor Shaft Lever Mounting Bolt [C]: 6.9 N·m
•
(0.7 kgf·m, 61 in·lb)
Install the KIPS cover.
•
Tighten:
Torque - KIPS Cover Bolts:
KX125-M1: 4.9 N·m (0.5 kgf·m, 43 in·lb)
KX125-M2
∼
: 8.8 N·m (0.9 kgf·m, 78 in·lb)
Right Engine Cover
KX250
•
Put a 9 mm (0.35 in.) spanner wrench [A] on the governor shaft lever upper end.
•
Turn the governor shaft lever counterclockwise with the wrench and fit the groove of the operating rod collar [B] to the boss of the governor shaft lever, and install the collar on the operating rod while turning the governor shaft lever clockwise.
•
After installing the collar, install the E-clip [A] on the operating rod [B].
•
Tighten the KIPS cover bolts.
Torque - KIPS Cover Bolts: 2.9 N·m (0.3 kgf·m, 26 in·lb)
•
Apply grease to the inside of the brake pedal boss.
•
Tighten the brake pedal mounting bolt.
Torque - Brake Pedal Mounting Bolt: 25 N·m (2.5 kgf·m, 18 fl·lb)
•
Fill the cooling system with coolant (see Coolant Inspection in the Periodic Maintenance chapter).
•
Fill the transmission with engine oil (see Transmission Oil
Change in the Periodic Maintenance chapter).
•
Check the rear brake.
•
Remove the right engine cover.
•
Turn the governor shaft lever [A] to the left, and remove the exhaust advancer assembly [B].
•
Remove the Allen bolts [C], and take off the advancer lever.
•
Pull the dust cover [D].
Right Engine Cover
•
Remove the plug screw [A] and take out the governor shaft lever positioning pin.
•
Pull the governor shaft lever [B] out of the right engine cover.
•
Pull off the water pump shaft (see Water Pump Shaft Removal in the Cooling System chapter).
•
The exhaust advancer assembly [A] consists of the following parts.
A. Pins
B. Rod
C. Guide
D. O-ring
E. Steel Balls
F. Holder
G. Needle Bearing
H. Spacer
I. Collar
J. Spring
K. Gear
•
Check the exhaust advancer assembly parts for damage.
Any damaged parts should be replaced with new ones.
•
When assembling, apply molybdenum disulfide grease between the rod and inside/outside diameter parts of the holder, needle bearing and spacer .
•
Apply high temperature grease to the oil seal lips before inserting the governor shaft lever.
•
Apply molybdenum disulfide grease to the surface of the lever shaft, and insert the governor shaft lever [A] into the right engine cover hole.
•
Insert the positioning pin [B] into the hole then fit it to the grove [C] of the shaft.
•
Tighten the governor shaft lever positioning plug screw
[D] securely.
Torque - Governor Shaft Lever Positioning Plug: 0.6 N·m
(0.06 kgf·m, 5 in·lb)
•
Install the dust cover.
Right Engine Cover
•
Apply a non-permanent locking agent to the threads of the advancer lever mounting Allen bolts.
•
Tighten the advancer lever mounting Allen bolts [A].
Torque - Exhaust Valve Advancer Lever Mounting Allen
Bolts: 3.9 N·m (0.4 kgf·m, 35 in·lb)
•
Fit the advancer lever pin [B] into the groove [C] on the exhaust advancer assembly [D], and install the assembly in the engine cover while turning the governor shaft lever to the left.
Clutch
•
Remove the clutch cover (see Clutch Cover Removal).
•
Remove the clutch spring bolts [A], spring, and clutch pressure plate [B].
•
Remove the push rod holder assembly [A], friction plates, steel plates, and push rod [B].
•
For KX125, Remove steel boll [C].
•
Remove the clutch hub nut [A] and washer.
NOTE
○
Use the clutch holder [B] to prevent the clutch hub from rotating.
Special Tool - Clutch Holder: 57001-1243
•
Remove the clutch hub and housing, needle bearing [A], and sleeve [B].
Clutch
•
Apply molybdenum disulfide grease to the outside of the sleeve.
•
Apply engine oil to the inside of the clutch housing gear and kickstarter driven gear.
•
Install the sleeve, needle bearing, clutch hub and housing.
○
Do not forget to install the thrust washer [A] before installing the clutch hub [B].
•
Tighten the clutch hub nut [A].
Torque - Clutch Hub Nut: 98 N·m (10.0 kgf·m, 72 ft·lb)
NOTE
○
Use the clutch holder [B] to prevent the clutch hub from rotating.
Special Tool - Clutch Holder: 57001-1243
•
For KX250, stake the clutch hub nut [A] in three points [B] to the spline grooves to secure it in place.
CAUTION
When staking the nut, be careful not to apply shock to the shaft and bearings. Such a shock could damage the shaft and/or bearings.
•
Install the friction plates and steel plates, starting with a friction plate and alternating them. Finishing with a friction plate.
CAUTION
If dry steel plates and friction plates are installed, apply transmission oil to the surfaces of each plate to avoid clutch plate seizure.
•
For KX125, the grooves [A] on the friction plate surfaces are cut tangentially and radially, install the first and last friction plates [B] so that the grooves run toward the center in the direction of the clutch housing rotation (counterclockwise viewed from the engine right side).
•
Apply molybdenum disulfide grease to the rubbing portion of the push rod holder.
•
Tighten the clutch spring bolts fixing the flywheel with the special tool.
Torque - Clutch Spring Bolts: 8.8 N·m (0.9 kgf·m, 78 in·lb)
Special Tool - Flywheel Holder: 57001-1313
Clutch
•
For KX125; check the release shaft lever positions [A].
○
Remove the magneto cover.
○
Pushing the release shaft lever [C] lightly upward measure the distance between the release shaft lever and clutch cable set position of crankcase [D].
View [E]
Release Shaft Lever Position
Standard:
46.9
∼
53.9 mm (1.85
∼
2.12 in.)(KX125-M1)
49.0
∼
55.6 mm (1.93
∼
2.19 in.)(KX125-M2
∼
)
If the lever position is not within the standard, select the correct thickness of adjusting washer(s) [B] according to the tables shown.
Adjusting Washers
Thickness
1.5 mm (0.06 in.)
1.0 mm (0.04 in.)
Part NUMBER
92200-1548
92200-0045
Release Shaft Lever Position and Adjusting Washer Selection
(KX125-M1)
Position Distance
46.9 mm to 53.9 mm (1.85
∼
2.12
in.) (Standard)
More than 53.9 mm (2.12 in.)
Less than 46.9 mm (1.85 in.)
Washer Thickness Qty
1.5 mm (0.06 in.)
1.0 mm (0.04 in.)
1.0 mm (0.04 in.)
1
1
2
(KX125-M2
∼
)
Position Distance
49.0 mm to 55.6 mm (1.93
∼
2.19
in.) (Standard)
More than 55.6 mm (2.19 in.)
Less than 49.0 mm (1.93 in.)
Washer Thickness Qty
1.5 mm (0.06 in.)
1.0 mm (0.04 in.)
1.0 mm (0.04 in.)
1
1
2
Remove the push rod holder assembly as necessary and reinstall the clutch.
○
Install the magneto cover.
•
Refer to the Clutch Plates Inspection in the Periodic Maintenance chapter.
•
Refer to the Clutch Plates Inspection in the Periodic Maintenance chapter.
Clutch
•
Since the spring [A] becomes shorter as it weakens, check its free length to determine its condition.
If any of the springs is shorter than the service limit, it must be replaced.
Clutch Spring Free Length
KX125
Standard:
Service Limit:
46.8 mm (1.843 in.)
44.9 mm (1.768 in.)
KX250
Standard:
Service Limit:
35 mm (1.378 in.)
33.6 mm (1.323 in.)
•
Measure the clearance between the tangs [A] on the friction plate and the fingers [B] of the clutch housing.
If this clearance is excessive, the clutch will be noisy.
If the clearance exceeds the service limit, replace the friction plates.
Friction Plate/Clutch Housing Clearance
KX125:
Standard: 0.04
∼
0.55 mm (0.0016
∼
0.0217 in.)
Service Limit: 0.9 mm (0.0354 in.)
KX250:
Standard:
Service Limit:
0.15
∼
0.45 mm (0.0059
0.8 mm (0.0315 in.)
∼
0.0177 in.)
•
Visually inspect where the teeth on the steel plates wear against the splines [A] of the clutch hub.
If there are notches worn into the splines, replace the clutch hub. Also, replace the clutch plates if their teeth are damaged.
•
Remove the clutch (see Clutch Removal).
•
Remove the clutch cable upper end (see Clutch Cable
Removal).
○
For KX125; remove the magneto cover.
•
Remove the tips [A] of the clutch cable.
•
Pull the lever and shaft assembly [B] out of the crankcase.
Clutch
•
Apply high temperature grease to the oil seal lips.
•
Apply engine oil to the bearing in the hole of the crankcase.
•
Insert the release shaft straight in to the hole of the crankcase.
•
Install the clutch (see Clutch Installation).
○
For KX125; install the magneto cover.
External Shift Mechanism
•
Remove:
Shift Pedal
Right Engine Cover (see Right Engine Cover Removal)
•
Clutch (see Clutch Removal)
Pull out the external shift shaft [A].
•
Remove the bolts [B] and take off the shift ratchet assembly [C] with collar.
•
Remove the nut [D], and take off the gear set lever [E].
•
Install the gear set lever.
○
Do not forget to install the color.
•
Tighten the gear set lever nut.
Torque - Gear Set Lever Nut: 8.8 N·m (0.9 kgf·m, 78 in·lb)
•
Set up the shift ratchet assembly as shown in the figure.
Ratchet [A]
Pawls [B]
Pins [C]
Springs [D]
•
Then install the ratchet assembly [A] to the ratchet plat [B] as shown in the figure.
•
Install the ratchet assembly to the shift drum.
•
Tighten:
Torque - Ratchet Plat Mounting Bolts: 8.8 N·m (0.9 kgf·m,
78 in·lb)
•
Before installing the shift shaft, apply high temperature grease to the oil seal lips and shift shaft splines.
•
Install the shift shaft.
○
Do not forget to install the collar [A].
•
Install:
Clutch (see Clutch Installation)
Right Engine Cover (see Right Engine Cover Installation)
External Shift Mechanism
•
Instal the shift pedal [A] as shown.
0
∼
20 mm (0
∼
0.79 in.) [B]
•
Tighten:
Torque - Shift Pedal Bolt: 9.8 N·m (1.0 kgf·m, 87 in·lb)
•
Check the shift shaft [A] for bending or damage to the splines.
If the shaft is bent, straighten or replace it. If the splines are damaged, replace the shift mechanism.
•
Check the return spring [B] for cracks or distortion.
If the spring is damaged in any way, replace it.
•
Check the shift mechanism arm [C] for distortion.
If the shift mechanism arm is damaged in any way, replace the shift mechanism.
•
Check the collar [D] for damage.
If the collar is damaged in any way, replace it.
•
Check the ratchet assembly for damage.
If ratchet, pawls, pins or springs are damaged in any way, replace them.
•
For KX250, Check that the return spring pin [A] is not loose.
If it is loose, unscrew it, apply a non-permanent locking agent to the threads, and tighten it.
Torque - External Shift Mechanism Return Spring Pin: 42
N·m (4.3 kgf·m, 31 ft·lb)
•
Check the gear set lever and its spring for cracks or distortion.
If the lever or spring is damaged in any way, replace them.
•
Visually inspect the shift drum cam.
If it is badly worn or if it shows any damage, replace it.
Primary Gear
•
•
Remove the right engine cover (see Right Engine Cover
Removal)
•
Remove the clutch (see Clutch Removal).
For KX125, remove the primary gear nut [A], spring washer, woodruff key, primary gear [B], and O-ring.
NOTE
○
Use the flywheel & pulley holder to prevent the crankshaft from the rotating.
Special Tool - Flywheel & Pulley Holder: 57001-1605
•
For KX250, remove the circlip [A], and take off the water pump drive gear [B] and primary gear [C].
Special Toos - Outside Circlip Pliers: 57001-144
•
KX125
Instal the O-ring.
•
Fit the woodruff key [B] on the crankshaft groove.
•
Install the spring washer so that concave side faces [A] inward.
•
Tighten the primary gear nut.
Torque - Primary Gear Nut: 59 N·m (6.0 kgf·m, 43 ft·lb)
NOTE
○
Use the flywheel & pulley holder to prevent the crankshaft from the rotating.
Special Toos - Flywheel & Pulley Holder: 57001-1605
KX250
•
Install the primary gear [A] so that chamfered side [B] faces outward.
•
Install the water pump drive gear [C] so that the chamfered side [D] faces outward.
•
Replace the old circlip with a new one.
Special Toos - Outside Circlip Pliers: 57001-144
Kickstarter
•
Remove:
Right Engine Cover
Clutch Housing
•
Pull the end of the kick spring [A] out of the hole in the crankcase.
•
Remove the kickstarter assembly [B].
•
Remove the bolts [A], take off the ratchet guide [B].
•
The kickstarter assembly consists of the following parts.
•
Check the kickstarter assembly parts for damage. Any damaged parts should be replaced with new ones.
A. Idle Gear
B. Circlip
C. Washer
D. Spring
E. Ratchet Gear
F. Kick Gear
G. Kick Shaft
H. Kick Spring
I. Spring Guide
•
Apply molybdenum disulfide grease to the inside of the kick gear and ratchet gear.
•
When assembling the ratchet gear [A] onto the kick shaft
[B], align the punch mark [C] on the ratchet gear with the punch mark [C] on the kick shaft.
•
Replace the circlips that were removed with new ones.
Special Tool - Outside Circlip Pliers: 57001-144
Kickstarter
•
Remove:
Right Engine Cover (see Right Engine Cover Removal)
•
Clutch Housing (see Clutch Removal)
For KX125, pull off the idle gear.
•
For KX250, remove the circlip [A] and pull off the idle gear
[B].
Special Tool - Outside Circlip Pliers: 57001-144
•
Apply molybdenum disulfide grease to the inside of the idle gear.
•
Replace the circlip with a new one.
Special Tool - Outside Circlip Pliers: 57001-144
Table of Contents
7
Exploded View
Exploded View
No.
Fastener
Engine Mounting Nuts:
1 KX125/250-M1
KX125/250-M2
∼
Engine Mounting Bracket Nut (Engine Side 10 mm):
2 KX125/250-M1
KX125/250-M2
∼
3 Engine Mounting Bracket Nuts (Frame Side 8 mm)
4 Swingarm Pivot Shaft Nut
5. Frame
6. Engine Mounting Bracket
7. Pivot Shaft
8. Swingarm
G: Apply grease.
N·m
44
49
44
49
29
98
Torque kgf·m
4.5
5.0
4.5
5.0
3.0
10.0
ft·lb
Remarks
33
36
33
36
22
72
Special Tool
Jack:
57001-1238
Engine Removal/Installation
•
Drain the engine oil (see Transmission Oil Change in the
Periodic Maintenance chapter).
•
Drain the coolant (see Coolant Inspection in the Periodic
Maintenance chapter).
•
Remove:
Radiator Shrouds
Side Covers
Seat
Fuel Tank
Water Hoses
Radiators
Expansion Chamber
Ignition Coil (KX250)
Spark Plug Cap
Carburetor (with Cables and Hoses)
Clutch Cable Lower End
Drive Chain
Engine Sprocket
Shift Pedal
Brake Pedal
•
Disconnect the magneto output lead, and free the leads from the clamp at the left side of the cylinder.
•
Unbolt the mounting bolts [A] and remove the engine mounting brackets [B].
•
Place a jack [A] under the frame to lift the motorcycle off the ground, and put blocks under the front and rear tires to steady the motorcycle.
WARNING
The swingarm pivot shaft also serves as the engine mounting bolt. Take precautions to insure the frame is well supported, and that the motorcycle will not fall over when the pivot shaft is removed.
•
Special Tool - Jack: 57001-1238
Remove the engine mounting bolts [B].
•
Pull out the swing arm pivot shaft [C].
•
Lift the engine out to the right.
Engine Removal/Installation
•
Tighten the following nuts.
Torque - Engine Mounting Nuts:
44 N·m (4.5 kgf·m, 33 ft·lb) (KX125/250-M1)
49 N·m (5.0 kgf·m, 36 ft·lb) (KX125/250-M2
∼
)
Engine Mounting Bracket Nuts 10 mm:
44 N·m (4.5 kgf·m, 33 ft·lb) (KX125/250-M1)
49 N·m (5.0 kgf·m, 36 ft·lb) (KX125/250-M2
∼
)
Engine Mounting Bracket Nuts 8 mm:
29 N·m (3.0 kgf·m, 22 ft·lb)
Swingarm Pivot Shaft Nut: 98 N·m (10.0 kgf·m, 72 ft·lb)
•
To route the leads, cables and hoses, refer to the Appendix chapter.
•
To install parts removed, refer to the appropriate chapters.
•
Fill the cooling system with coolant (see Cooling System chapter).
•
Fill the transmission with engine oil (see Transmission Oil
Change in the Periodic Maintenance chapter).
•
Adjust:
Throttle Cable
Clutch Cable
Drive Chain
Rear Brake
Table of Contents
8
Exploded View
KX125:
Exploded View
No.
Fastener
1 Output Shaft Bearing Retaining Screws
2
Shift Drum Bearing Retaining Screws (KX125-M1)
Shift Drum Bearing Retaining Bolts (KX125-M2
∼
)
3 Engine Oil Drain Bolt
4 Crankcase Bolts
5 Flywheel Bolt
6 Shift Drum Operating Cam Bolt
7. Left Crankcase
8. Right Crankcase
9. Crankshaft Assembly
10. Flywheel Magneto
11. Stator
12. Drive Shaft
13. Output Shaft
14. Engine Sprocket
15. Shift Fork
16. Shift Rod
17. Shift Drum
18. Shift Drum Operating Cam
19. Shift Pedal
20. Shift Shaft
A: KX125M6F Model
∼
EO: Apply engine oil to the transmission gears and shift forks, etc.
G: Apply high temperature grease.
L: Apply a non-permanent locking agent.
LG: Apply liquid gasket to the left and right case mating surface.
O: Apply 2-stroke engine oil.
R: Replacement parts
20
8.8
22
24
N·m
5.4
6.4
8.8
Torque kgf·m ft·lb
0.55
48 in·lb
0.65
56 in·lb
0.9
78 in·lb
2.0
0.9
14.5
78 in·lb
2.2
2.4
16
17
Remarks
L
L
L
L
Exploded View
KX250:
Exploded View
No.
1 Crankcase Bolts
6 Flywheel Nut
Fastener
2 Output Shaft Bearing Retaining Screws
3 Shift Drum Bearing Retaining Bolts
4 Engine Oil Drain Bolt
5 Drive Shaft Bearing Retaining Bolts
7 Shift Drum Operating Cam Bolt
N·m
8.8
5.4
8.8
20
8.8
78
24
8. Left Crankcase
9. Right Crankcase
10. Crankshaft Assembly
11. Stator
12. Flywheel Magneto
13. Drive Shaft
14. Output Shaft
15. Engine Sprocket
16. Shift Fork
17. Shift Rod
18. Shift Drum Operating Cam
19. Shift Drum
20. Shift Pedal
21. Shift Shaft
EO: Apply engine oil to the transmission gears and shift forks, etc.
G: Apply high temperature grease.
L: Apply a non-permanent locking agent.
LG: Apply liquid gasket to the left and right case mating surface.
M: Apply molybdenum disulfide grease.
O: Apply 2-stroke engine oil.
R: Replacement parts.
Torque kgf·m
0.9
0.55
0.9
2.0
0.9
8.0
2.4
ft·lb
78 in·lb
48 in·lb
78 in·lb
14.5
78 in·lb
58
17
Remarks
L
L
Specifications
Item
Standard
KX125/250-M1
Transmission Oil
Grade API SE, SF or SG
API SA or SJ with JASO MA
API SH, SJ or SL with JASO MA
(KX125M7F
∼
)
SAE 10W-40 Viscosity
Capacity:
KX125
KX250
0.7 L (0.74 US qt)
0.85 L (0.90 US qt)
Crankshaft, Connecting Rod
Connecting Rod Bend 0.03 mm (0.0012 in.)/100 mm (3.937
in.) or less
Connecting Rod Big End
Radial Clearance:
KX125
KX250
0.036
∼
0.047 mm (0.0014
∼
0.0019
in.)
0.037
∼
0.049 mm (0.0015
∼
0.0019
in.)
Connecting Rod Big End Side
Clearance:
KX125
KX250
Crankshaft Runout
0.40
∼
0.50 mm (0.0157
∼
0.0197 in.)
0.45
∼
0.55 mm (0.0177
∼
0.0217 in.)
TIR 0.03 mm (0.0012 in.) or less
Transmission
Gear Backlash: 0.02
∼
0.20 mm (0.0008
∼
0.0078 in.)
Shift Fork Ear Thickness:
KX125
KX250
4.90
∼
5.00 mm (0.1768
∼
0.1969 in.)
4.40
∼
4.50 mm (0.1732
∼
0.1772 in.)
Gear Shift Fork Groove Width:
KX125
KX250
5.05
∼
5.15 mm (0.1988
∼
0.2028 in.)
4.55
∼
4.65 mm (0.1791
∼
0.1830 in.)
Shift Fork Guide Pin Diameter 5.90
∼
6.00 mm (0.2323
∼
0.2362 in.)
Shift Drum Groove Width 6.05
∼
6.20 mm (0.2382
∼
0.2440 in.)
Service Limit
– – –
– – –
– – –
– – –
0.2 mm (0.008 in.)/100 mm (3.937 in.)
0.10 mm (0.004 in.)
0.10 mm (0.004 in.)
0.70 mm (0.028 in.)
0.70 mm (0.028 in.)
TIR 0.05 mm (0.002 in.)
0.30 mm (0.012 in.)
4.80 mm (0.189 in.)
4.30 mm (0.169 in.)
5.25 mm (0.207 in.)
4.75 mm (0.187 in.)
5.80 mm (0.228 in.)
6.25 mm (0.246 in.)
Special Tools and Sealant
Bearing Puller Adapter:
57001-136
Bearing Driver Set:
57001-1129
Outside Circlip Pliers:
57001-144
Bearing Puller:
57001-158
Crankshaft Jig:
57001-1174
Kawasaki Bond (Liquid Gasket - Silver):
92104-002
Crankcase Splitting Tool Assembly:
57001-1098
Transmission Oil
In order for the transmission and clutch to function properly, always maintain the transmission oil at the proper level and change the oil periodically.
WARNING
Motorcycle operation with insufficient, deteriorated, or contaminated transmission oil will accelerated wear and may result in transmission seizure, and injury.
•
Refer to the Transmission Oil Change in the Periodic
Maintenance chapter.
•
Refer to the Transmission Oil Change in the Periodic
Maintenance chapter.
Crankcase
•
Remove the engine (see Engine Removal in the Engine
Removal/Installation chapter).
•
Set the engine on a clean surface while parts are being removed.
•
Remove:
Magneto Cover
Cylinder Head (see Cylinder Head Removal in the Engine Top End chapter)
Cylinder (see Cylinder Removal in the Engine Top End chapter)
Piston (see Piston Removal in the Engine Top End chapter)
Right Engine Cover (see Right Engine Removal in the
Engine Right Side chapter)
Clutch (see Clutch Removal in the Engine Right Side chapter)
Primary Gear (see Primary Gear Removal in the Engine
Right Side chapter)
Kickstarter Assembly (see Kickshaft Removal in the Engine Right Side chapter)
Kickstarter Idle Gear (see Idle Gear Removal in the Engine Right Side chapter)
External Shift Mechanism (see External Shift Mechanism Removal in the Engine Right Side chapter)
Shift Ratchet Assembly (see External Shift Mechanism
Removal in the Engine Right Side chapter)
Gear Set Lever [A]
Shift Drum Operating Cam [B]
Output Shaft Sleeve [C] and O-ring [D] (KX250, O-rings)
Flywheel Magneto and Stator (see Flywheel Magneto
Removal in the Electrical System chapter)
Reed Valve (KX125) (see Reed Valve Removal in the
Fuel System chapter)
Crankcase
•
Remove the crankcase bolts [A].
•
Install the crankcase splitting tool [A] and bearing puller adapter [B] into the left side of the crankcase. Be certain to screw the tool in all the way.
Special Tools - Crankcase Splitting Tool Assembly: 57001
-1098
Bearing Puller Adapter: 57001-136
•
Tighten the bolt on the crankcase splitting tool to split the crankcase halves.
•
Once the crankcase is split, remove the crankcase splitting tool, and lift off the left crankcase half.
•
Pull out the shift rods [A].
•
Disengage the shift fork guide pins from the shift drum grooves.
•
Take off the shift drum [B]
•
Remove the shift forks [C] from the transmission gears.
•
Take out the drive shaft [D] and output shaft [E] together with their gear meshed.
•
Remove the crankshaft from the right crankcase half using a press.
CAUTION
Do not remove the bearings and the oil seals unless it is necessary.
Removal may damage them.
Crankcase
•
Before fitting the left crankcase half on the right crankcase half, note the following:
○
Chip off the old gasket from the mating surfaces of the crankcase halves, and clean off the crankcase with a high
-flash point solvent. After cleaning, apply engine oil to the transmission gears, shift drum, shift forks and so on.
○
Be sure to replace any oil seal removed with a new one.
Press in the new oil seal using a press and suitable tools so that the seal surface is flush with the surface of the crankcase.
○
Apply high temperature grease to the oil seal lips.
○
Press in the ball bearings using the bearing driver set until the bearing is bottomed.
Special Tool - Bearing Driver Set: 57001-1129
○
Install the bearing for the output shaft into the left crankcase half so that stepped side faces [A] inside.
CAUTION
Install the bearings for the crankshaft in the right and left crankcase so that their sealed sides face toward the oil seal side.
○
Tighten the output and drive shaft bearing retaining bolts/screws securely.
Torque - Drive Shaft Bearing Retaining Bolts: 8.8 N·m (0.9
kgf·m, 78 in·lb)
Output Shaft Bearing Retaining Screws: 5.4 N·m
(0.55 kgf·m, 48 in·lb)
○
For KX125M; install the release shaft needle bearing as shown.
[A] Oil Seal
[B] Needle Bearing
[C] Needle Bearing Position
KX125-M1
∼
M2: 3.5 ±0.2 mm (0.138 ±0.008 in.)
KX125-M3
∼
: 3.3 ±0.2 mm (0.130 ±0.008 in.)
○
If the crankshaft bearings stay on the crankshaft when splitting the crankcase, remove the bearings from the crankshaft and reinstall them in the crankcase, and then assemble the crankcase (see Crankshaft Removal and
Installation).
•
Turn the crankshaft [A] to BDC, and install the crankshaft jig [C] between the flywheels opposite the connecting rod
[B] big end to protect flywheel alignment as shown.
○
If the crankshaft has been removed from the crankcase, install the jig between the crankshaft flywheels before pressing the crankshaft into the right crankcase half.
•
Special Tool - Crankshaft Jig: 57001-1174
•
Install the transmission shaft as a set (see this chapter).
Install the shift fork, shift drum and shift rod.
Crankcase
•
Check to see that the crankcase knock pins [A] and O-ring
[B] (KX125) are in place on the right crankcase half. If any of them has been removed, replace it with a new one.
•
Apply liquid gasket to the mating surface [A] of the crankcase half.
Sealant - Kawasaki Bond (Liquid Gasket - Silver): 92104
-002
•
Using a suitable tool on the left crankcase to press [A] around the hole for the crankshaft, fit the crankcase halves together with a press on the tool.
NOTE
○
Constantly check the alignment of the two crankcase halves, and the position of the transmission shafts, and shift drum. The front and rear of the crankcase must be pushed together evenly.
•
Remove the crankshaft jig from the flywheels.
•
Tighten the crankcase bolts starting with the ones around the crankshaft, and then the farther ones.
○
At this time, tighten the crankcase bolt [A] and clamp [B] for the breather hoses together.
Torque - Crankcase Bolts: 8.8 N·m (0.9 kgf·m, 78 in·lb)
Crankcase
•
Check to see that the crankshaft, drive shaft, and output shaft all turn freely (in the neutral position).
If the crankshaft will not turn, probably the crankshaft is not centered; tap the appropriate end of the crankshaft with a mallet to reposition it.
•
Spinning the output shaft, shift the transmission through all the gears to make certain there is no binding and that all the gears shift properly.
•
Install the parts removed in the reverse order of removal, and refer to the appropriate chapters.
○
Replace the O-ring on the output shaft with a new one.
Crankshaft, Connecting Rod
•
Split the crankcase (see Crankcase Splitting).
•
Remove the transmission shafts (see Transmission Shaft
Removal).
•
Using a press, remove the crankshaft from the right crankcase.
○
If the bearings stay on the crankshaft when splitting the crankcase or removing the crankshaft from the right crankcase, remove the bearings from the crankshaft with a bearing puller [A] and adapter [B].
Special Tools - Bearing Puller: 57001-158
Bearing Puller Adapter: 57001-136
•
When installing the crankshaft bearings [B], apply high temperature grease to the outer sides of the bearings, and then press them into the crankcase using the bearing driver [A] until the bearing bottoms against the step.
○
Position the crankcase half so that the main bearing housing is seated on a suitable press fixture.
○
Install the crankshaft bearing so that the mark side faces out.
Special Tool - Bearing Driver Set: 57001-1129
•
Insert the crankshaft jig [C] between the crankshaft flywheels opposite the connecting rod [B] big end to protect flywheel alignment as shown, and press the crankshaft
[A] into the right crankcase.
○
When pressing, position the jig in the crankcase opening so the jig does not hit the crankcase.
Special Tool - Crankshaft Jig: 57001-1174
•
Apply 2-stroke oil to the connecting rod big end bearing.
Since assembly of the crankshaft demands exacting tolerances, the disassembly and reassembly of the crankshaft can only be done by a shop having the necessary tools and equipment.
•
If it should be necessary to disassemble the crankshaft, use a press to remove the crankpin.
Since the assembly of the crankshaft demands exacting tolerances, the disassembly and reassembly of the crankshaft can only be done by a shop having the necessary tools and equipment.
•
Reassemble the crankshaft according to the standard tolerances in Specifications.
○
Connecting rod bend, twist
○
Connecting rod big end radial clearance.
○
Cold-fitting tolerance between crankpin and flywheels.
○
Side clearance between the connecting rod big end and one of flywheels.
○
Crankshaft runout.
Crankshaft, Connecting Rod
•
Set the crankshaft in a flywheel alignment jig or on V blocks, and place a dial gauge against the connecting rod big end.
•
Push the connecting rod first towards the gauge and then in the opposite direction. The difference between the two gauge readings is the radial clearance.
Connecting Rod Big End Radial Clearance
Standard:
KX125: 0.036
∼
0.047 mm (0.0014
∼
0.0019 in.)
KX250: 0.037
∼
0.049 mm (0.0015
∼
0.0019 in.)
Service Limit:
KX125: 0.10 mm (0.004 in.)
KX250: 0.10 mm (0.004 in.)
If the radial clearance exceeds the service limit, the crankshaft should be either replaced or disassembled and the crankpin, needle bearing, and connecting rod big end examined for wear.
In case of serious seizure with damaged flywheels, the crankshaft must be replaced.
In case of less serious damage, disassemble the crankshaft and replace the crankpin, needle bearing, side washers, and connecting rod.
•
Measure the side clearance [A] of the connecting rod with a thickness gauge.
Connecting Rod Big End Side Clearance
Standard:
KX125: 0.40
∼
0.50 mm (0.0157
∼
0.0197 in.)
KX250: 0.45
∼
0.55 mm (0.0177
∼
0.0217 in.)
Service Limit: 0.70 mm (0.028 in.)
If the clearance exceeds the service limit, replace the crankshaft.
•
Set the crankshaft in a flywheel alignment jig or on V blocks, and place a dial gauge against the points indicated.
•
Turn the crankshaft slowly. The maximum difference in gauge readings is the crankshaft runout.
(A): KX125 - 8.0 mm (0.315 in.)
KX250 - 8.5 mm (0.335 in.)
Crankshaft Runout
Standard: TIR 0.03 mm (0.0012 in.) or less
Service Limit: TIR 0.05 mm (0.002 in.)
If the runout at either point exceeds the service limit, align the flywheels so that the runout falls within the service limit.
Crankshaft, Connecting Rod
•
In the case of horizontal misalignment, which is the most common, strike the projecting rim of the flywheel with a plastic, soft lead, or brass hammer as indicated in the figure.
•
Recheck the runout with a dial gauge, repeating the process until the runout falls within the service limit.
○
Vertical misalignment is corrected either by driving a wedge in between the flywheels or by squeezing the flywheel rims in a vise, depending on the nature of the misalignment. In cases of both horizontal and vertical misalignment, correct the horizontal misalignment first.
CAUTION
Don’t hammer the flywheel at point "A".
If flywheel misalignment cannot be corrected by the above method, replace the crankpin or the crankshaft itself.
Transmission
•
Split the crankcase (see Crankcase Splitting).
•
Pull off the shift rods [A], and disengage the shift fork guide pins from the shift drum grooves.
•
•
Remove the shift drum [B].
Remove the shift forks [C] from the transmission gears.
•
Take out the drive shaft [D] and output shaft [E] together, with their gears meshed.
•
Hold the drive shaft [A] and output shaft [B] together, with their gears meshed, and fit them into the right crankcase half.
•
To install the shift forks and shift drum (see Shift Drum and Fork Installation).
•
Remove the transmission shafts (see Transmission Shaft
Removal).
•
Using the circlip pliers to remove the circlips, disassemble the transmission shaft.
Special Tool - Outside Circlip Pliers: 57001-144
•
Apply engine oil liberally to the transmission shaft, gears
• and bearings.
Replace any circlips that were removed with new ones.
○
Always install circlips [A] so that the opening [B] is aligned with a spline groove [C].
Special Tool - Outside Circlip Pliers: 57001-144
•
The drive shaft gears can be identified by size; the smallest diameter gear is 1st gear, and the largest is 5th
(KX250) or 6th (KX125). Be sure that all parts are put back in the correct sequence, and facing the proper direction, and that all circlips and the washers are properly in place.
Transmission
KX125:
A. 1st gear
B. 5th gear
(13T; part of drive shaft)
(24T; plain side faces right)
C. 3rd/4th gear (17T/17T; larger gear faces right)
D. 6th gear
E. 2nd gear
F. Circlip
(25T; plain side faces left)
(14T; stepped side faces left)
KX250:
A. 1st gear
B. 5th gear
C. 3rd gear
D. 4th gear
E. 2nd gear
F. Circlip
(15T; part of drive shaft)
(23T; dog recesses face left)
(17T; fork groove goes to the left side of the gear teeth)
(21T; dog recesses face right)
(16T; chamfered side faces right)
•
The output shaft gears can be identified by size; the largest diameter gear is 1st gear, and the smallest is
5th (KX250) or 6th (KX125). Be sure that all parts are put back in the correct sequence and facing the proper direction, and that all circlips are properly in place.
KX125:
A. 2nd gear
B. 6th gear
C. 3rd gear
D. 4th gear
E. 5th gear
F. 1st gear
G. Circlip
(26T; dog recesses face right)
(25T; fork groove goes to the right side of the gear teeth)
(26T; dog recesses face left)
(22T; dog recesses face right)
(27T; fork groove goes to the left side of the gear teeth)
(31T; plain side faces right)
KX250:
A. 2nd gear
B. 4th gear
(23T; dog recesses face right)
(21T; fork groove goes to the right side of the gear teeth)
C. 3rd gear
D. 5th gear
(20T; dog recesses face left)
(20T; fork groove goes to the left side of the gear teeth)
E. 1st gear
(27T; dog recesses face left)
F. Circlip
G. Collar
•
Check that each gear spins or slides freely on the transmission shaft without binding after assembly.
Transmission
•
Apply a little engine oil to the shift fork [A] ears, and fit the shift forks into the gear grooves.
Shift Fork Identification
KX125:
Drive shaft 3rd gear and 4th gear shift fork [A]
Output shaft 5th gear shift fork
[B]
Output shaft 6th gear shift fork
[C] ears are shorter than those of the other two shift forks guide pin goes to left side of the ears guide pin goes to right side of the ears
KX250:
Drive shaft 3rd gear and 4th gear shift fork [A]
Output shaft 4th gear shift fork [B]
Output shaft 5th gear shift fork [C] ears are shorter than those of the other two shift forks guide pin goes to center side of the ears guide pin goes to left side of the ears
•
Tighten the shift drum bearing retaining screws or bolts.
Torque - Shift Drum Bearing Retaining Screws: 6.4 N·m
(0.65 kgf·m, 56 in·lb) (KX125
∼
M1)
Shift Drum Bearing Retaining bolts: 8.8 N·m (0.9
kgf·m, 78 in·lb) (KX250), (KX125-M2
∼
)
•
Install the shift dram [C].
•
Fit the shift fork guide pins into the corresponding shift drum grooves.
•
Apply a little engine oil to the shift rods [A], and slide them into the shift forks [B].
•
Holding the shift drum with the suitable too and tighten the shift drum operating plate bolt.
Torque - Shift Drum Operating Cam Bolt: 24 N·m (2.4 kgf·m,
17 ft·lb)
Transmission
•
Visually inspect the shift forks, and replace any fork that is bent. A bent fork could cause difficulty in shifting, or allow the transmission to jump out of gear when under power.
A. 90°
•
Measure the thickness of the shift fork ears [A], and measure the width [B] of the shift fork grooves in the transmission gears.
If the thickness of a shift fork ear is less than the service limit, the shift fork must be replaced.
Gear Shift Fork Ear Thickness
Standard:
KX125 4.9
∼
5.0 mm (0.1768
∼
0.1969 in.)
KX250 4.4
∼
4.5 mm (0.1732
∼
0.1772 in.)
Service Limit:
KX125 4.8 mm (0.189 in.)
KX250
4.3 mm (0.169 in.)
If a gear shift fork groove is worn over the service limit, the gear must be replaced.
Gear Shift Fork Groove Width
Standard:
KX125
KX250
5.05
∼
5.15 mm (0.1988
∼
0.2028 in.)
4.55
∼
4.65 mm (0.1791
∼
0.1830 in.)
Service Limit:
KX125
5.25 mm (0.207 in.)
KX250 4.75 mm (0.187 in.)
•
Measure the diameter [A] of each shift fork guide pin, and measure the width [B] of each shift drum groove.
If the guide pin on any shift fork is less than the service limit, the fork must be replaced.
Shift Fork Guide Pin Diameter
Standard: 5.90
∼
6.00 mm (0.2323
∼
0.2362 in.)
Service Limit: 5.80 mm (0.228 in.)
If any shift drum groove is worn over the service limit, the drum must be replaced.
Shift Drum Groove Width
Standard: 6.05
∼
6.20 mm (0.2382
∼
0.2440 in.)
Service Limit: 6.25 mm (0.246 in.)
Transmission
•
Visually inspect the gear teeth on the transmission gears.
Repair lightly damaged gear teeth with an oilstone. The gear must be replaced if the teeth are badly damaged.
When the gear is repaired or replaced, the driving gear should also be inspected and repaired or replaced if necessary.
•
Visually inspect the gear dogs [A] and gear dog holes [B].
Replace any damaged gears or gears with excessively worn dogs or dog holes.
•
Check the ball bearing on the crankcase.
Since the ball bearings are made to extremely close tolerances, the wear must be judged by feel rather than measurement. Clean each bearing in a high-flash point solvent, dry it (do not spin the bearing while it is dry), and oil it with transmission oil.
○
Spin the bearing by hand to check its condition.
If the bearing is noisy, does not spin smoothly, or has any rough spots, replace it.
Table of Contents
9
Exploded View
Exploded View
No.
Fastener
1 Spoke Nipple
2 Front Axle Nut
3 Front Axle Clamp Bolts
4 Rear Axle Nut
5. Spoke
6. Front Tire
7. Rim
8. Front Axle
9. Swingarm
10. Rear Tire
11. Rear Axle
A: KX125/250-M1 model
B: KX125/250-M2 model
∼
G: Apply grease.
WL: Apply soap and water solution, or rubber lubricant.
R: Replacement Parts
N·m
2.2
78
20
108
Torque kgf·m
0.22
8.0
2.0
11.0
ft·lb
19 in·lb
58
14.5
80
Remarks
Specifications
Item
Wheels (Rims)
Rim Runout (with tire installed):
Axial
Radial
Axle Runout/ 100 mm
KX125
Rim Size:
Front
Rear
KX250
Rim Size:
Front
Rear
Tires Air Pressure
Front and Rear
Tires
Standard Tire:
KX125
Front:
Size
Make
Type:
Rear:
(KX125-M1
∼
M2)
(KX125-M3
∼
)
Size
Make
Type:
KX250
(KX125-M1
∼
M2)
(KX125-M3
∼
)
Front:
Size
Make
Type
Rear:
Size
Make
Type
(EUR): Europe Model
Standard
TIR 1.0 mm (0.039 in.) or less
TIR 1.0 mm (0.039 in.) or less
TIR 0.1 mm (0.004 in.) or less
21 × 1.60
19 × 1.85
21 × 1.60
19 × 2.15
100 kPa (1.0 kgf/cm², 14 psi)
80/100-21 51M
DUNLOP
D739FA, Tube (EUR) D755FJ, Tube
D742F, Tube (other than EUR)
100/90-19 57M
DUNLOP
D739, Tube (EUR) D755G, Tube
D756, Tube (other than EUR)
80/100-21 51M
BRIDGESTONE (EUR) DUNLOP
M601, Tube (EUR) D755FJ, Tube
110/90-19 62M
BRIDGESTONE (EUR) DUNLOP
M602, Tube (EUR) D755J, Tube
Service Limit
TIR 2 mm (0.079 in.)
TIR 2 mm (0.079 in.)
TIR 0.2 mm (0.008 in.)
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
– – –
Special Tools
Inside Circlip Pliers:
57001-143
Rim Protector:
57001-1063
Bead Breaker Assembly:
57001-1072
Bearing Driver Set:
57001-1129
Jack:
57001-1238
Wheels (Rims)
•
Using the jack [A] under the frame, and stabilize the motorcycle, and raise the front wheel off the ground.
Special Tool - Jack: 57001-1238
•
For KX125/250-M1 model, unscrew the guard screws [A] and remove the guard [B].
•
Unscrew the axle nut [A].
•
Loosen the left axle clamp bolts [B].
•
For KX125/250-M2 model
∼
; as shown in the figure.
•
Loosen the right axle clamp bolts [A], remove the axle [B], and pull out the wheel. Take off the collar [C] and cap [D] from each side of the front hub.
CAUTION
Do not lay the wheel on the ground with the disc facing down. This can damage or warp the disc.
Place blocks under the wheel so the disc does not touch the ground.
Wheels (Rims)
•
For KX125/250-M2 model
∼
; as shown in the figure.
•
Insert a wood wedge between the disc brake pads. This prevents them from being moved out of their proper position, should the brake lever be squeezed accidentally.
•
Apply grease to the seals.
•
Fit the projection on the cap to the groove on the collar.
•
Install the caps [B], collars [A] on the left (longer collar)
• and right (shorter collar) side of the hub.
Insert the axle [C] from right side.
•
Unbolt the right axle clamp bolts [D] temporally.
•
Tighten the axle nut [E].
Torque - Front Axle Nut: 78 N·m (8.0 kgf·m, 58 ft·lb)
•
Remove the jack. Push and release the handlebars five times or more apply the front brake to move the front forks so that the axle shaft has a snug fit with the axle holder.
•
Tighten the left axle clamp bolts [F] first, and tighten the right axle clamp bolts.
Torque - Front Axle Clamp Bolts: 20 N·m (2.0 kgf·m, 14.5
ft·lb)
NOTE
○
Tighten the two clamp bolts alternately two times to ensure even tightening torque.
•
For KX125/250-M2 model
∼
; as shown in the figure.
•
Check the front brake for good braking power and no brake drag.
WARNING
Do not attempt to drive the motorcycle until a full brake lever is obtained by pumping the brake lever until the pads are against the disc. The brake will not function on the first application of the lever if this is not done.
Wheels (Rims)
•
Using the jack under the frame so that the rear wheel is raised off the ground.
Special Tool - Jack: 57001-1238
•
Remove the clip [A] from the master link using pliers, and free the drive chain [B] from the rear sprocket.
•
Remove
Disc Cover [A]
Cotter Pin [B]
•
Axle Nut [C]
Pull out the axle [D].
•
Move the rear wheel back with the rear caliper installed.
•
Take off the collar and cap from the each side of the rear hub.
CAUTION
Do not lay the wheel on the ground with the disc facing down. This can damage or warp the disc.
Place blocks under the wheel so the disc does not touch the ground.
•
Insert a wood wedge between the brake pads. This prevents them from being moved out of their proper position, should the brake pedal be squeezed accidentally.
•
Fit the brake holder stop [A] with the stop grooves [B] against the swingarm stop space [C] with the stop projection [D].
Wheels (Rims)
•
Fit the projection on the cap to the groove on the collar.
•
Install the collars [A] on the left and right side of the hub.
•
Install the drive chain. Install the master link clip [A] so that the closed end [B] of the “U” points in the direction of chain rotation [C].
•
Check the drive chain slack (see Final Drive chapter).
•
Tighten the axle nut.
Torque - Rear Axle Nut: 108 N·m (11.0 kgf·m, 80 ft·lb)
•
Install the new cotter pin [A] and spread its end.
NOTE
○
When inserting the cotter pin, if the slots in the nut do not align with the cotter pin hole in the axle shaft, tighten the nut clockwise [A] up to next alignment.
○
It should be within 30 degree.
○
Loosen once tighten again when the slot goes past the nearest hole.
•
Install disc cover.
•
Check the rear brake for good braking power and no brake drag.
WARNING
Do not attempt to drive the motorcycle until a full brake pedal is obtained by pumping the brake pedal until the pads are against the disc. The brake will not function on the first application of the pedal if this is not done.
Wheels (Rims)
•
Place the jack under the frame so that the front/rear wheel is raised off the ground.
Special Tool - Jack: 57001-1238
•
Spin the wheel lightly, and check for roughness or binding.
If roughness or binding is found, replace the hub bearings.
•
Visually inspect the front and rear axles for damage.
If axle is damaged or bent, replace it.
•
Refer to the Spoke Tightness Inspection in the Periodic
Maintenance chapter.
•
Refer to the Rim Runout Inspection in the Periodic Maintenance chapter.
•
Visually inspect the front and rear axle for damages.
If the axle is damaged or bent, replace it.
•
Place the axle in V blocks that are 100 mm (3.937 in.) [A] apart, and set a dial gauge on the axle at a point halfway between the blocks. Turn the axle to measure the runout.
The difference between the highest and lowest dial readings is the amount of runout.
Axle Runout/100 mm (3.937 in.)
Standard: TIR 0.1 mm (0.004 in.) or less
Service Limit: TIR 0.2 mm (0.008 in.)
If runout exceeds the service limit, replace the axle.
Tires
•
Refer to the Tire Air Pressure Inspection/Adjustment in the Periodic Maintenance chapter.
•
Refer to the Tires Inspection in the Periodic Maintenance chapter.
CAUTION
Do not lay the wheel on the ground with the disc facing down. This can damage or warp the disc.
Place blocks under the wheel so the disc does not touch the ground.
•
Remove the wheel from the motorcycle (see Wheels Removal).
•
To maintain wheel balance, mark [A] the valve stem position on the tire with chalk so that the tire can be reinstalled
• in the same position.
Take out the valve core [B] to let out the air.
•
Remove the valve stem nut [C].
○
When handling the rim, be careful not to damage the rim flanges.
•
Loosen the bead protector nut.
•
Lubricate the tire beads and rim flanges on both sides with a soap and water solution or rubber lubricant. This helps the tire beads slip off the rim flanges.
CAUTION
Never lubricate with mineral oil (engine oil) or gasoline because they will cause deterioration of the tire.
•
Break the beads away from both sides of the rim with the bead breaker [A].
Special Tool - Bead Breaker Assembly: 57001-1072
•
Step on the side of the tire opposite valve stem, pry the tire off the rim with the tire iron [A] of the bead breaker protecting the rim with rim protectors [B].
Special Tools - Rim Protector: 57001-1063
Bead Breaker Assembly: 57001-1072
CAUTION
Take care not to inset the tire irons so deeply that the tube gets damaged.
•
Remove the tube when one side of the tire is pried off.
•
Pry the tire off the rim.
Tires
NOTE
○
The tires should be installed so that the year and week of manufacture [A] or the ID serial faces to left side.
•
•
Inspect the rim and tire, and replace them if necessary.
Install the tube.
•
Apply a soap and water solution, or rubber lubricant to the rim flange and tire beads.
•
Position the tire on the rim so that the valve [A] is at the tire balance mark [B] (the chalk mark made during removal, or the yellow paint mark on a new tire. see Removal).
•
Insert the valve stem into the rim, and screw the nut on loosely.
•
Fit the rim protectors and use tire irons to install the tire bead.
NOTE
○
To prevent rim damage, be sure to place the rim protectors at any place the tire irons are applied.
•
Pry one side of the tire back onto the rim. Fit the bead protector into the tire.
•
Pry the other side of the tire onto the rim, starting at the side opposite the valve.
○
Take care not to insert the tire irons so deeply that the tube is damaged.
•
Install the other side of the tire bead onto the rim in the same manner.
•
Inspect that the tube is not pinched between the tire and rim.
•
Tighten the bead protector nut and valve stem nut, and put on the valve cap.
•
Inspect and adjust the air pressure after installing.
Hub Bearings
•
Remove the wheel (see Wheel Removal).
CAUTION
Do not lay the wheel on the ground with the disc facing down. This can damage or warp the disc.
Place blocks under the wheel so that the disc does not touch the ground.
•
Remove the oil seals and circlips.
Special Tools - Inside Circlip Pliers: 57001-143
•
Remove the hub bearing by tapping evenly around the bearing inner race as shown.
[A] Bar
[B] Distance Collar
[C] Hub Bearing
•
Before installing the wheel bearings, blow any dirt or foreign particles out of the hub [B] with compressed air to
• prevent contamination of the bearings.
Replace the bearings with new ones.
•
Lubricate them and install them using the bearing driver set [A] so that the marked or shielded sides face out.
○
Press in the bearings until they are bottomed.
Special Tool - Bearing Driver Set: 57001-1129
•
Replace the circlips and oil seals with new ones.
•
Press in the oil seals [A] so that the seal surface is flush
[B] with the end of the hole.
•
Apply high temperature grease to the oil seal lips.
Special Tool - Bearing Driver set: 57001-1129 [C]
NOTE
○
It is not necessary to remove any bearings for inspection. If any bearings are removed, they will need to be replaced with new ones.
•
Spin [A] it by hand to check its condition.
If it is noisy, does not spin smoothly, or has any rough spots, it must be replaced.
•
Examine the bearing seal [B] for tears or leakage.
If the seal is torn or is leaking, replace the bearing.
Table of Contents
10
Exploded View
Exploded View
No.
Fastener
1 Rear Sprocket Nuts
2 Rear Axle Nut
3 Engine Sprocket Cover Bolts
4. Engine Sprocket
5. Output Shaft
6. Chain Slipper
7. Swingarm
8. Chain Guide
9. Locknut
10. Adjusting Bolt
11. Chain Adjuster
12. Drive Chain
13. Rear Sprocket
14. Rear Axle
A: KX125-M1
∼
M2 Model
G: Apply grease.
O: Apply oil.
R: Replacement Parts
N·m
34
108
4.9
Torque kgf·m
3.5
11.0
0.5
ft·lb
25
80
43 in·lb
Remarks
Specifications
Item
Drive Chain
Chain Slack
Chain 20-link Length
Standard Chain:
Make:
Type:
Length:
KX125-M1
KX125-M2
∼
KX250
Sprocket
Rear Sprocket Warp (Runout)
Standard
52
∼
62 mm (2.05
∼
2.44 in.)
317.5
∼
318.2 mm (12.50
∼
12.53 in.)
DAIDO
D.I.D 520DMA2
112 Links
114 Links
114 Links
TIR 0.4 mm (0.016 in.) or less
Service Limit
– – –
323 mm (12.72 in.)
– – –
– – –
– – –
– – –
– – –
TIR 0.5 mm (0.020
in.)
Special Tools
Outside Circlip Pliers:
57001-144
Jack:
57001-1238
Drive Chain
•
Refer to the Drive Chain Inspection in the Periodic Maintenance chapter.
•
Refer to the Drive Chain Inspection in the Periodic maintenance chapter.
•
Check that the rear end [A] of the left chain adjuster aligns with the same swing arm mark [B] as the right chain adjuster.
WARNING
Misalignment of the wheel will result in abnormal wear, and may result in an unsafe riding condition.
This procedure is the same as Drive Chain Inspection.
•
Refer to the Drive Chain Wear Inspection in the Periodic
Maintenance chapter.
•
Refer to the Drive Chain Lubrication in the Periodic Maintenance chapter.
•
Remove the engine sprocket cover.
•
Remove the clip [A] from the master link using pliers, and free the drive chain from the rear sprocket.
•
Remove the drive chain from the chassis.
•
Fit the drive chain back onto the sprockets with the ends at the rear sprocket.
•
Install the master link from the frame side.
•
Install the clip [A] so that the closed end [B] of the "U" pointed in the direction of chain rotation .
•
Adjust the drive chain slack (see Drive Chain Slack Adjustment).
•
Inspect the rear brake (see the Brakes chapter).
Sprockets
•
Remove:
Engine Sprocket Cover [A]
Drive Chain [B] (free of engine sprocket)
•
Remove the circlip [C], and pull off the engine sprocket
[D].
Special Tool - Outside Circlip Pliers: 57001-144
•
Replace the circlip with a new one.
•
Install the circlip so that the tooth is aligned with a spline groove.
Special Tool - Outside Circlip Pliers: 57001-144
•
For KX250, clamp the air vent hoses with clamps which are installed together with engine sprocket cover.
•
Tighten:
Torque - Engine Sprocket Cover Bolts: 4.9 N·m (0.5 kgf·m,
43 in·lb)
•
Remove the rear wheel (see Wheels/Tires chapter).
CAUTION
Do not lay the wheel on the ground with the disc facing down. This can damage or warp the disc.
Place blocks under the wheel so that the disc does not touch the ground.
•
Unscrew the rear sprocket bolts [A], and remove the rear sprocket [B].
•
Install the rear sprocket [A] so that the marked side [B] faces out.
•
Install the rear sprocket bolts and tighten the nuts.
Torque - Rear Sprocket Nuts: 34 N·m (3.5 kgf·m, 25 ft·lb)
•
Refer to the Sprocket Inspection in the Periodic Maintenance chapter.
•
Refer to the Sprocket Inspection in the Periodic Maintenance chapter.
Table of Contents
11
Exploded View
Exploded View
No.
Fastener
1 Front Master Cylinder Clamp Bolts
2 Brake Lever Pivot Bolt
3 Brake Lever Pivot Bolt Locknut
4 Brake Hose Banjo Bolts
5 Brake Pad Bolt
6 Caliper Bleed Valve
7 Caliper Mounting Bolts
8 Brake Disc Mounting Bolts
9. Front Brake Reservoir
10. Brake Lever
11. Brake Lever Adjuster
12. Locknut
13. Brake Hose
14. Clamps
15. Front Caliper
16. Brake Pad
17. Piston
18. Front Disc
A: KX125/250-M1 model
B: KX125/250-M2 model
∼
BF: Apply brake fluid.
L: Apply a non-permanent locking agent.
R: Replacement Parts
Si: Apply Silicone grease.
25
18
7.8
25
9.8
N·m
8.8
5.9
5.9
Torque kgf·m
0.9
0.60
0.60
2.5
1.8
0.8
2.5
1.0
ft·lb
78 in·lb
52 in·lb
52 in·lb
18
13
69 in·lb
18
87 in·lb
Remarks
L
Exploded View
Exploded View
No.
Fastener
1 Brake Hose Banjo Bolts
2 Rear Master Cylinder Mounting Bolts
3 Rear Master Cylinder Push Rod Locknut
4 Caliper Bleed Valve
5 Brake Pad Bolt
6 Rear Brake Pad Bolt Plug
7 Caliper Holder Shaft
8 Brake Pedal Mounting Bolt
9 Brake Disc Mounting Bolts
10. Brake Hose
11. Rear Master Cylinder
12. Brake Pedal
13. Rear Caliper Cover
14. Rear Caliper
15. Piston
16. Brake Pad
17. Rear Disc
BF: Apply brake fluid.
EO: Apply 2-stoke engine oil.
G: Apply high temperature grease.
L: Apply a non-permanent locking agent.
R: Replacement Parts
Si: Apply Silicone grease.
7.8
18
2.5
27
N·m
25
9.8
18
25
23
Torque kgf·m
2.5
1.0
1.8
0.8
1.8
0.25
2.8
2.5
2.3
ft·lb
18
87 in·lb
13
69 in·lb
13
22 in·lb
20
18
17
Remarks
L
L
Specifications
Item
Brake Adjustment
Brake Lever Play
Brake Fluid
Recommended Disc Brake Fluid:
Type:
Front
Rear
Brake Pads
Lining Thickness:
Front
Rear
Brake Disc
Thickness:
Front
Rear
Runout
Standard
Adjustable (to suit rider)
DOT3 or DOT4
DOT4
3.8 mm (0.150 in.)
6.4 mm (0.252 in.)
2.85
∼
3.15 mm (0.112
∼
0.124 in.)
3.85
∼
4.15 mm (0.152
∼
0.163 in.)
TIR 0.25 mm (0.098 in.) or less
Service Limit
– – –
– – –
– – –
1 mm (0.04 in.)
1 mm (0.04 in.)
2.5 mm (0.10 in.)
3.5 mm (0.14 in.)
TIR 0.3 mm (0.01 in.)
Special Tools
Inside Circlip Pliers:
57001-143
Jack:
57001-1238
Brake Lever, Brake Pedal
•
Refer to the Brake Lever Play Adjustment in the Periodic
Maintenance chapter.
The brake pedal position and pedal play should not be adjusted. There is no pedal position adjustment device as such. The only adjustment is master cylinder push rod length.
NOTE
○
Usually it is not necessary to adjust the push rod length, but always adjust it when the rear master cylinder [A] is disassembled.
○
When the brake pedal is in its rest position, measure the length [B] indicated in the figure.
Push Rod Locknut [C]
Standard Length [B]:
79.3 mm (3.12 in.) (KX125/250-M1)
67.3 mm (2.65 in.) (KX125/250-M2
∼
)
If the length is not within the specified length, adjust the clevis [A] as follows.
○
Loosen the push rod locknut [B].
○
Pull out the cotter pin [C] and the joint pin [D].
○
Turn the clevis to obtain the specified length.
○
Tighten the locknut.
Torque - Rear Master Cylinder Push Rod Locknut: 18 N·m
(1.8 kgf·m, 13 ft·lb)
○
Install the joint pin and new cotter pin.
NOTE
○
If the pedal position is incorrect after adjusting the master cylinder push rod, the brake pedal may be deformed or incorrectly installed.
•
Remove:
Cotter Pin [A]
Joint Pin [B]
Washer
Brake Lever, Brake Pedal
•
Remove the mounting bolt [A] and take off the brake pedal and return spring [B].
•
Inspect the pedal O-ring for signs of damage. If necessary, replace them with new one.
•
Apply high temperature grease to the shaft portion of the brake pedal, and install the pedal with return spring onto the frame.
•
Tighten:
Torque - Brake Pedal Mounting Bolt: 25 N·m (2.5 kgf·m, 18
•
ft·lb)
•
Inspect the brake pedal position.
Install the joint pin, washer and a new cotter pin.
Brake Fluid
WARNING
When working with the disc brake, observe the precautions listed below.
1. Never reuse old brake fluid.
2. Do not use fluid from a container that has been left unsealed or that has been open for a long time.
3. Do not mix two types and brands of fluid for use in the brake. This lowers the brake fluid boiling point and could cause the brake to be ineffective. It may also cause the rubber brake parts to deteriorate.
4. Don’t leave the reservoir cap off for any length of time to avoid moisture contamination of the fluid.
5. Don’t change the fluid in the rain or when a strong wind is blowing.
6. Except for the disc pads and disc, use only disc brake fluid, isopropyl alcohol, or ethyl alcohol for cleaning of the brake parts. Do not use any other fluid for cleaning these parts. Gasoline, engine oil, or any other petroleum distillate will cause deterioration of the rubber parts. Oil spilled on any part will be difficult to wash off completely and will eventually deteriorate the rubber used in the disc brake.
7. When handling the disc pads or disc, be careful that no disc brake fluid or any oil gets on them. Clean off any fluid or oil that inadvertently gets on the pads or disc with a high-flash point solvent. Do not use one which will leave an oily residue. Replace the pads with new ones if they cannot be cleaned satisfactorily.
8. Brake fluid quickly ruins painted surfaces; any spilled fluid should be completely wiped up immediately.
9. If any of the brake line fittings or the bleed valve is opened at any time, the AIR MUST BE BLED FROM
THE BRAKE LINE.
•
Refer to the Brake Fluid Level Inspection in the Periodic
Maintenance chapter.
•
Refer to the Brake Fluid Change in the Periodic Maintenance chapter.
Brake Fluid
The brake fluid has a very low compression coefficient so that almost all the movement of the brake lever or pedal is transmitted directly to the caliper for braking action. Air, however, is easily compressed. When air enters the brake lines, brake lever or pedal movement will be partially used in compressing the air. This will make the lever or pedal feel spongy, and there will be a loss in braking power.
WARNING
Be sure to bleed the air from the brake whenever brake lever or pedal action feels soft or spongy, after the brake fluid is changed, or whenever a brake line fitting has been loosened for any reason.
NOTE
○
The procedure to bleed the front brake line is as follows.
Bleeding the rear brake line is the same as for the front brake.
•
Remove the reservoir cap, and check that there is plenty of fluid in the reservoir.
•
With the reservoir cap off, slowly pump the brake lever several times until no air bubbles can be seen rising up through the fluid from the holes at the bottom of the reservoir.
○
Bleed the air completely from the master cylinder by this operation.
•
Install the reservoir cap.
•
Attach a clear plastic hose to the bleed valve on the caliper, and run the other end of the hose into a con-
• tainer.
Bleed the brake line and the caliper as follows:
○
Repeat this operation until no more air can be seen coming out into the plastic hose.
1. Pump the brake lever until it becomes hard, and apply the brake and hold it [A].
2. Quickly open and close the bleed valve while holding the brake applied [B].
3. Release the brake [C].
NOTE
○
The fluid level must be checked often during the bleeding operation and replenished with fresh brake fluid as necessary. If the fluid in the reservoir runs almost out any time during bleeding operation, the bleeding operation must be done over again from the beginning since air will have entered the line.
○
Tap the brake hose lightly from the caliper to the reservoir for easier bleeding.
Brake Fluid
•
•
Remove the clear plastic hose.
•
Tighten the bleed valves, and install the rubber caps.
Torque - Caliper Bleed Valve: 7.8 N·m (0.8 kgf·m, 69 in·lb)
•
Check the fluid level.
After bleeding is done, check the brake for good braking power, no brake drag, and no fluid leakage.
WARNING
Do not attempt to drive the motorcycle until a full brake lever or pedal is obtained by pumping the brake lever or pedal until the pads are against the disc. The brake will not function on the first application of the lever or pedal if this in not done.
Caliper
•
Front Brake
Loosen the banjo bolt [A] so as not to spill brake fluid.
•
Remove the caliper mounting bolts [B].
•
Remove the banjo bolt and take off the brake hose from the caliper [C].
•
If the caliper is to be disassembled after removal and if compressed air is not available, remove the piston using the following steps before disconnecting the brake hose from the caliper.
○
Remove the pads.
○
Pump the brake lever to remove the piston.
•
For KX125/250-M2 model
∼
; as shown in the figure.
Rear Brake
•
Unbolt the guard bolts [A] and remove the rear caliper guard [B].
•
Loosen the banjo bolt [C] so as not to spill brake fluid.
•
Loosen the brake pad bolt [A] and caliper holder shaft [B] before the caliper removal if the caliper is to be disassembled.
NOTE
○
If the caliper is to be disassembled after removal and compressed air is not available, disassemble the caliper before brake hose removal (see Caliper Disassembly).
•
Remove the rear wheel. (see Rear Wheel Removal in the
Wheels/Tires chapter)
•
Unscrew the banjo bolt and remove the brake hose [C] from the caliper (see Brake Hose Removal/Installation).
CAUTION
Immediately wipe up any brake fluid that is spilled.
Caliper
•
Tighten the brake pad bolts if it was removed.
Torque - Brake Pad Bolts: 18 N·m (1.8 kgf·m, 13 ft·lb)
Front Brake:
•
Install the caliper and tighten the bolts.
Torque - Caliper Mounting Bolts: 25 N·m (2.5 kgf·m, 18 ft·lb)
Rear Brake:
•
Before install the caliper, install the rear wheel (see Rear
•
Wheel Installation in the Wheels/Tires chapter).
Install the brake hose lower end.
○
Replace the washers that are on each side of hose fitting with new ones.
•
Tighten:
Torque - Brake Hose Banjo Bolt: 25 N·m (2.5 kgf·m, 18 ft·lb)
•
Bleed the brake line (see Bleeding the Brake Line).
•
Check the brake for good braking power, no brake drag, and no fluid leakage.
WARNING
Do not attempt to drive the motorcycle until a full brake lever or pedal is obtained by pumping the brake lever or pedal until the pads are against the disc. The brakes will not function on the first application of the lever or pedal if this is not done.
•
Remove the front/rear caliper (see Caliper removal).
•
Remove the pads and spring (see Pad Removal).
•
Remove the caliper holder, shaft rubber friction boot and
• cover.
Using compressed air, remove the piston(s).
○
Cover the caliper opening with a clean, heavy cloth [A].
○
Remove the piston(s) by lightly applying compressed air
[B] to the hose joint opening.
WARNING
To avoid serious injury, never place your fingers or palm inside the caliper opening. If you apply compressed air into the caliper, the piston(s) may crush your hand or fingers.
NOTE
○
If the caliper is to be disassembled after removal and compressed air is not available, remove the piston(s) using the following three steps before disconnecting the brake hose from the caliper.
○
Prepare a container for brake fluid, and perform the work above it.
○
Remove the pads and spring (see Pad Removal).
○
Pump the brake lever or pedal to remove the caliper piston(s).
•
Remove the dust seal(s) and fluid seal(s).
•
Remove the bleed valve and rubber cap.
Caliper
•
Clean the caliper parts except for the pads.
CAUTION
For cleaning the parts, use only disc brake fluid, isopropyl alcohol, or ethyl alcohol.
•
Tighten the bleed valve with rubber cap.
Torque - Caliper Bleed Valve: 7.8 N·m (0.8 kgf·m, 69 in·lb)
•
Replace the fluid seals which are removed with new ones.
○
Apply brake fluid to the fluid seals [A], and install them into the cylinders by hand.
•
Replace the dust seals with new ones if they are damaged.
○
Apply brake fluid to the dust seals [B], and install them into the cylinders by hand.
•
Apply brake fluid to the outside of the pistons [C], and push them into each cylinder by hand.
•
Install the anti-rattle spring [A] in the caliper as shown.
•
Replace the shaft rubber boot [A] and dust cover [B] if they are damaged.
•
Apply a thin coat of silicone grease to the caliper holder shafts [C] and holder holes (PBC is a special high temperature, water-resistant grease).
○
For rear caliper, tighten the caliper holder shaft.
•
Torque - Caliper Holder Shaft: 27 N·m (2.8 kgf·m, 20 ft·lb)
•
Install the pads (see Pads Installation).
Wipe up any spilled brake fluid on the caliper.
The fluid seal around the piston maintains the proper pad/disc clearance. If this seal is not in good condition, pad wear will increase, and constant pad drag on the disc will raise brake and brake fluid temperature.
•
Replace the fluid seals under any of the following conditions: (a) fluid leakage around the pad; (b) brakes overheat; (c) there is a large difference in left and right pad wear; (d) the seal is stuck to the piston. If the fluid seal is replaced, replace the dust seal as well. Also, replace all seals every other time the pads are changed.
•
Inspect that the dust seals and covers are not cracked, worn, swollen, or otherwise damaged.
If they show any damage, replace them.
Caliper
•
Visually inspect the piston and cylinder surfaces.
Replace the cylinder and piston if they are badly scored or rusty.
The caliper body must slide smoothly on the caliper holder shafts. If the body does not slide smoothly, one pad will wear more than the other, pad wear will increase, and constant drag on the disc will raise brake and brake fluid temperature.
•
Inspect too see if the caliper holder shafts are not badly worn or stepped, or the rubber boot is not damaged.
If the shafts or rubber boot are damaged, replace the shafts, rubber boot, and the caliper holder.
•
Remove the plug and the pad bolt [A].
•
Take the piston side pad [B].
•
Push the caliper holder toward the piston, and then remove another pad [C] from the caliper holder.
•
For KX125/250-M2 model
∼
; as shown in the figure.
Caliper
•
Push the caliper pistons in by hand as far as they will go.
•
Install the piston side pad first, and then another pad.
•
Tighten the brake pad bolt and plug.
Torque - Brake Pad Bolt: 18 N·m (1.8 kgf·m, 13 ft·lb)
Rear Brake Pad Bolt Plug: 2.5 N·m (0.25 kgf·m, 22 in·lb)
•
Check the brake for good braking power, no brake drag, and no fluid leakage.
WARNING
Do not attempt to drive the motorcycle until a full brake lever or pedal is obtained by pumping the brake lever or pedal until the pads are against the disc. The brake will not function on the first application of the lever or pedal if this is not done.
•
Refer to the Brake Pad Wear Inspection in the Periodic
Maintenance chapter.
Master Cylinder
CAUTION
Brake fluid quickly ruins painted or plastic surfaces; any spilled fluid should be completely wished up immediately.
•
Remove the banjo bolt [A] to disconnect the upper brake hose from the master cylinder (see Brake Hose Removal/Installation).
•
When removing the brake hose, temporarily secure the end of the brake hose to some high place to keep fluid loss to a minimum.
•
Unscrew the clamp bolts [B], and take off the master cylinder [C] as an assembly with the reservoir and brake lever.
•
Position the master cylinder so that the vertical parting line [A] of the front master cylinder clamps align with the punch mark [B] on the handlebar.
•
The master cylinder clamp must be installed with the arrow mark [A] upward.
○
Tighten the upper clamp bolt [B] first, and then the lower clamp bolt [C] There will be a gap at the lower part of the clamp after tightening.
Torque - Front Master Cylinder Clamp Bolts: 8.8 N·m (0.9
kgf·m, 78 in·lb)
•
Replace the washers that are on each side of hose fitting with new ones.
•
Tighten the brake hose banjo bolt.
•
Torque - Brake Hose Banjo Bolt: 25 N·m (2.5 kgf·m, 18 ft·lb)
Bleed the brake line (see Bleeding the Brake Line).
•
Inspect the brake for good braking power, no brake drag, and no fluid leakage.
•
Remove the cotter pin [A].
•
Pull off the joint pin [B] with washer.
NOTE
○
Pull off the joint pin while pressing down the brake pedal.
•
Unscrew the master cylinder mounting bolts [C], and remove the master cylinder.
•
Unscrew the brake hose banjo bolt [D] (see Brake Hose
Removal/Installation).
•
When removing the brake hose, temporarily secure the end of the brake hose to some high place to keep fluid loss to a minimum.
Master Cylinder
•
Replace the cotter pin with a new one.
•
Replace the washers are on each side of hose fitting with new ones.
•
Tighten the following:
Torque - Brake Hose Banjo Bolt: 25 N·m (2.5 kgf·m, 18 ft·lb)
Rear Master Cylinder Mounting Bolts: 9.8 N·m (1.0
•
kgf·m, 87 in·lb)
Bleed the brake line (see Bleeding the Brake Line).
•
Inspect the brake for good braking power, no brake drag, and no fluid leakage.
•
Inspect the brake pedal position (master cylinder push rod length).
•
Remove the front master cylinder.
•
Remove the reservoir cap and diaphragm, and pour the brake fluid into a container.
•
Unscrew the locknut and pivot bolt, and remove the brake lever.
•
Push the dust cover [A] out of place, and remove the circlip [B].
Special Tool - Inside Circlip Pliers: 57001-143
•
Remove the washer [C], pull out the piston [D], secondary cup [E], primary cup [F], and return spring [G].
CAUTION
Do not remove the secondary cup from the piston since removal will damage it.
•
Remove the rear master cylinder.
•
Remove the reservoir cap and diaphragm, and pour the brake fluid into a container.
•
Slide the dust cover [A] on the push rod [B] out of place, and remove the retainer [C].
•
Special Tool - Inside Circlip Pliers: 57001-143
Pull out the push rod with the piston stop [D].
•
Take off the piston [E], secondary cup [F], primary cup [G], and return spring [H].
CAUTION
Do not remove the secondary cup from the piston since removal will damage it.
Master Cylinder
•
Before assembly, clean all parts including the master cylinder with brake fluid or alcohol.
•
Apply brake fluid to the removed parts and to the inner wall of the cylinder.
CAUTION
Except for the disc pads and disc, use only disc brake fluid, isopropyl alcohol, or ethyl alcohol for cleaning brake parts. Do not use any other fluid for cleaning these parts. Gasoline, engine oil, or any other petroleum distillate will cause deterioration of the rubber parts. Oil spilled on any part will be difficult to the wash off completely, and will eventually deteriorate the rubber used in the disc brake.
•
Take care not to scratch the piston or the inner wall of the cylinder.
•
Tighten the brake lever pivot bolt and the locknut securely.
•
Disassemble the front and rear master cylinders.
•
Inspect that there are no scratches, rust or pitting on the inner wall of each master cylinder [A] and on the outside of each piston [B].
If a master cylinder or piston shows any damage, replace them.
•
Inspect the primary [C] and secondary [D] cups.
If a cup is worn, damaged, softened (rotted), or swollen, the piston assembly should be replace to renew the cups.
If fluid leakage is noted at the brake lever, the piston assembly should be replaced to renew the cup.
•
Inspect the dust covers [E] for damage.
If they are damaged, replace them.
•
Inspect that the relief [F] and supply [G] ports are not plugged.
If the small relief port becomes plugged, the brake pads will drag on the disc. Blow the ports clean with compressed air.
•
Inspect the piston return springs [H] for any damage.
If a spring is damaged, replace it.
[K] Rear Master Cylinder.
Brake Disk
•
Visually inspect the disc [A].
If it is scratched or damaged, replace the disc.
•
Measure the thickness of each disc at the point [B] where it has worn the most.
Replace the disc if it has worn past the service limit.
Thickness
Standard:
Front
Rear
Service Limit:
Front
Rear
2.85
∼
3.15 mm 2.85
∼
3.15 mm
3.85
∼
4.15 mm (0.152
∼
0.163 in.)
2.5 mm (0.10 in.)
3.5 mm (0.14 in.)
•
Place a jack under the motorcycle so that the front/rear wheel is raised off the ground.
Special Tool - Jack: 57001-1238
•
Set up a dial gauge against the disc [A] as illustrated.
○
For the front disc, turn the handlebar fully to one side.
•
Measure the disc runout while rotating the wheel slowly
[B].
If the runout exceeds the service limit, replace the disc.
Runout
Standard: TIR 0.25 mm (0.098 in.) or less
Service Limit: TIR 0.3 mm (0.01 in.)
Brake Hose
CAUTION
Brake fluid quickly ruins painted or plastic surfaces; any spilled fluid should be completely wiped up immediately with watered cloth.
•
When removing the brake hose, take care not to spill the brake fluid on the painted or plastic parts.
•
When removing the brake hose, temporarily secure the end of the brake hose to some high place to keep fluid loss to a minimum.
•
There are washers on each side of the brake hose fitting.
Replace them with new ones when installing.
•
When installing the hoses, avoid sharp bending, kinking, flattening or twisting, and route the hoses according to the
Cable, Wire and Hose Routing section in the Appendix chapter.
•
Tighten the banjo bolts at the hose fittings.
Torque - Brake Hose Banjo Bolts: 25 N·m (2.5 kgf·m, 18 ft·lb)
•
Bleed the brake line after installing the brake hose (see
Bleeding the Brake Line).
•
Refer to the Brake Hoses and Connections Inspection in the Periodic Maintenance chapter.
Table of Contents
Exploded View...................................
Specifications ....................................
Special Tools .....................................
Front Fork ..........................................
Air Pressure Inspection................
Rebound Damping Adjustment ....
Adjustment ................................
(Simplify) ...................................
Oil Change/Oil Level Adjustment
(each fork leg) ...........................
Front Fork Removal .....................
Front Fork Installation ..................
fork leg) .....................................
Front Fork Assembly....................
Inner Tube Inspection ..................
Guide Bush Inspection.................
Dust Seal/Oil Seal Inspection ......
Spring Tension Inspection............
Rear Suspension (Uni-Trak)..............
Rear Shock Absorber: ....................
Rebound Damping Adjustment ....
Adjustment ................................
Spring Preload Adjustment ..........
Spring Tension Inspection............
Rear Shock Absorber Removal ...
Rear Shock Absorber Installation 12-34
Spring Replacement ....................
Disassembly (Oil Change) ........
Rear Shock Absorber Assembly ..
Rear Shock Absorber Scrapping .
Swingarm...........................................
Swingarm Removal......................
Swingarm Installation...................
Swingarm Bearing Removal ........
Swingarm Bearing Installation .....
Drive Chain Guide, Chain Slipper
Wear Inspection ........................
Tie-Rod, Rocker Arm.........................
Tie-Rod Removal .........................
Tie-Rod Installation ......................
Rocker Arm Removal...................
Rocker Arm Installation................
Tie-Rod and Rocker Arm Bearing
Removal ....................................
Tie-Rod and Rocker Arm Bearing
Installation .................................
Needle Bearing Inspection...........
Uni-Trak Maintenance .......................
Uni-Trak Linkage Inspection ........
Inspection..................................
Inspection..................................
12
Exploded View
KX125/250-M1:
Exploded View
No.
Fastener
1 Front Fork Top Plug
2 Front Fork Clamp Bolts (Upper, Lower)
3 Steering Stem Head Nut
4 Piston Rod Nut
5 Front Axle Clamp Bolts
6 Front Fork Cylinder Valve Assembly
7. Screw
8. O-Ring
9. Damper
10. Washer
11. Spring Seat
12. Spring
13. Rebound Damping Adjuster Rod
14. Spring Guide
15. Piston Rod
16. Fork Cylinder
17. Outer Tube
18. Guide Bush
19. Washer
20. Oil Seal
21. Retaining Ring
22. Dust Seal
23. Inner Tube
24. Gasket
25. Cap
26. Steering Stem Head
27. Steering Stem
28. Fork Guide
29. Fork Protector
30. Front Fender Mounting Bolts
L: Apply a non-permanent locking agent to the threads.
N·m
29
20
98
28
20
54
Torque kgf·m
3.0
2.0
10.0
2.9
2.0
5.5
ft·lb
22
14.5
72
21
14.5
40
Remarks
L
Exploded View
KX125/250-M2
∼
Exploded View
No.
Fastener
1 Front Fork Top Plug
2 Front Fork Clamp Bolts (Upper, Lower)
3 Steering Stem Head Nut
4 Piston Rod Nut
5 Front Axle Clamp Bolts
6 Front Fork Cylinder Valve Assembly
7. Screw
8. O-ring
9. Spring Seat
10. Spring
11. Rebound Damping Adjuster Rod
12. Spring Guide
13. Piston Rod
14. O-ring
15. Guide Stay Nut
16. Snap Ring
17. Stopper
18. Piston Holder
19. Fork Cylinder
20. Outer Tube
21. Fork Guide
22. Guide Bush
23. Washer
24. Oil Seal
25. Retaining Ring
26. Dust Seal
27. Guide Bush
28. Inner Tube
29. Gasket
30. Cap
31. Steering Stem Head
32. Steering Stem
33. Fork Protector
34. Front Fender Mounting Bolts
L: Apply a non-permanent locking agent to the threads.
N·m
29
20
98
28
20
54
Torque kgf·m
3.0
2.0
10.0
2.9
2.0
5.5
ft·lb
22
14.5
72
21
14.5
40
Remarks
L
Exploded View
KX125/250-M1:
Exploded View
No.
Fastener
1 Swingarm Pivot Shaft Nut
2 Rocker Arm Pivot Nut
3 Tie-Rod Mounting Nut (Front, Rear)
4 Rear Shock Absorber Mounting Nut (Upper)
5 Rear Shock Absorber Mounting Nut (Lower)
6. Pivot Shaft
7. Swingarm
8. Rocker Arm
9. Tie-Rod
10. Rear Shock Absorber Cylinder
11. Bladder
12. Cap
13. Circlip
14. Valve Cap
15. Locknut
16. Adjusting Nut
17. Spring
18. Spring Guide
19. Circlip
20. Piston Rod Assembly
21. Piston
22. O-ring
23. Oil Seal
24. Stopper
25. Rear Shock Absorber
G: Apply grease.
N·m
98
83
83
39
34
Torque kgf·m
10.0
8.5
8.5
4.0
3.5
ft·lb
72
61
61
29
25
Remarks
Exploded View
KX125/250-M2
∼
Exploded View
No.
Fastener
1 Swingarm Pivot Shaft Nut
2 Tie-Rod Mounting Nut (Front, Rear)
3 Rocker Arm Pivot Nut
4 Rear Shock Absorber Mounting Nut (Upper)
5 Rear Shock Absorber Mounting Nut (Lower)
6. Pivot Shaft
7. Swingarm
8. Rocker Arm
9. Tie-Rod
10. Rear Shock Absorber Cylinder
11. Air Bleeder Bolt
12. O-ring
13. Bladder
14. Cap
15. Circlip
16. Valve Cap
17. Locknut
18. Adjusting Nut
19. Spring
20. Spring Guide
21. Circlip
22. Piston Rod Assembly
23. Piston
24. O-ring
25. Oil Seal
26. Stopper
27. Rear Shock Absorber
G: Apply grease.
L: Apply a non-permanent locking agent to the threads.
N·m
98
83
83
39
34
Torque kgf·m
10.0
8.5
8.5
4.0
3.5
ft·lb
72
61
61
29
25
Remarks
Specifications
KX125/250-M1:
Item
Front Fork
Air Pressure
Rebound Damping Adjustment
(from the seated position adjuster turned fully clockwise):
Compression Damping Adjustment
(from the seated position adjuster turned fully clockwise):
KX125
KX250
Oil Viscosity
Standard
Atmospheric pressure
13 clicks counterclockwise
14 clicks counterclockwise
13 clicks counterclockwise
KHL15-10 (KAYABA 01) or equivalent
Oil Capacity:
KX125
KX250
Oil Level (fully compressed, spring removed):
KX125
652 ±4 mL (22.04 ±0.14 US oz.)
664 ±4 mL (22.45 ±0.14 US oz.)
KX250
Fork Spring Free Length
Rear Suspension (Uni-Trak)
Rear Shock Absorber:
Rebound Damping Adjustment
(from the seated position adjuster fully clockwise) Turned:
KX125
KX250
Spring Preload Adjustment
(Adjusting nut position from the center of the mounting hole upper):
KX125
135 ±2 mm (5.31 ±0.08 in.)
(from top of outer tube)
125 ±2 mm (4.92 ±0.08 in.)
(from top of outer tube)
460 mm (18.11 in.)
12 clicks counterclockwise
10 clicks counterclockwise
112 mm (4.41 in.)
KX250 117 mm (4.61 in.)
Rear Shock Spring Free Length 260 mm (10.24 in.)
Gas Reservoir:
Compression Damping Adjustment
(from the seated position adjuster turned fully clockwise):
KX125
KX250
Gas Pressure
13 clicks counterclockwise
12 clicks counterclockwise
980 kPa (10 kgf/cm², 142 psi)
Service Limit
– – –
(Adjustable Range)
16 clicks
(Adjustable Range)
16 clicks
– – –
– – –
(Adjustable Range)
100
∼
145 mm
(3.94
∼
5.71 in.)
450 mm (17.72 in.)
(Adjustable Range)
16 clicks
(Adjustable Range)
109
∼
127.5 mm
(4.29
∼
5.02 in.)
109
∼
129.5 mm
(4.29
∼
5.10 in.)
255 mm (10.04 in.)
(Adjustable Range)
16 clicks
– – –
Specifications
Item Standard
Tie-Rod, Rocker Arm:
Sleeve Outside Diameter:
Large
Small
19.987
∼
20.000 mm (0.7869
∼
0.7874 in.)
15.987
∼
16.000 mm (0.6294
∼
0.6299 in.)
Rocker Arm Mounting Bolt Runout TIR 0.1 mm (0.004 in.) or less
Service Limit
19.85 mm (0.781 in.)
15.85 mm (0.624 in.)
TIR 0.2 mm (0.008 in.)
Specifications
KX125/250-M2
:
Item
Front Fork
Air Pressure
Rebound Damping Adjustment
(from the seated position adjuster turned fully clockwise):
Compression Damping Adjustment
(from the seated position adjuster turned fully clockwise):
KX125
KX250
Oil Viscosity
Standard
Atmospheric pressure
14 clicks counterclockwise
10 clicks counterclockwise
10 clicks counterclockwise
KHL15-10 (KAYABA 01) or equivalent
Oil Capacity:
KX125
KX250
Oil Level (fully compressed, spring removed):
KX125
565 ±4 mL (19.10 ±0.14 US oz.)
578 ±4 mL (19.54 ±0.14 US oz.)
KX250
Fork Spring Free Length
Rear Suspension (Uni-Trak)
Rear Shock Absorber:
Rebound Damping Adjustment
(from the seated position adjuster fully clockwise) Turned:
KX125
KX250
Spring Preload Adjustment
(Adjusting nut position from the center of the mounting hole upper):
KX125
105 ±2 mm (4.13 ±0.08 in.)
(from top of outer tube)
88 ±2 mm (3.46 ±0.08 in.)
(from top of outer tube)
460 mm (18.11 in.)
11 clicks counterclockwise
10 clicks counterclockwise
111 mm (4.37 in.)
KX250 112 mm (4.41 in.)
Rear Shock Spring Free Length 260 mm (10.24 in.)
Gas Reservoir:
Compression Damping Adjustment
(from the seated position adjuster turned fully clockwise):
KX125
KX250
Gas Pressure
13 clicks counterclockwise
10 clicks counterclockwise
980 kPa (10 kgf/cm², 142 psi)
Service Limit
– – –
(Adjustable Range)
16 clicks
(Adjustable Range)
16 clicks
– – –
– – –
– – –
(Adjustable Range)
70
∼
120 mm
(2.76
∼
4.72 in.)
450 mm (17.72 in.)
(Adjustable Range)
16 clicks
(Adjustable Range)
109
∼
127.5 mm
(4.29
∼
5.02 in.)
109
∼
129.5 mm
(4.29
∼
5.10 in.)
255 mm (10.04 in.)
(Adjustable Range)
16 clicks
– – –
Specifications
Item Standard
Tie-Rod, Rocker Arm
Sleeve Outside Diameter:
Large
Small
19.987
∼
20.000 mm (0.7869
∼
0.7874 in.)
15.987
∼
16.000 mm (0.6294
∼
0.6299 in.)
Rocker Arm Mounting Bolt Runout TIR 0.1 mm (0.004 in.) or less
Service Limit
19.85 mm (0.781 in.)
15.85 mm (0.624 in.)
TIR 0.2 mm (0.008 in.)
Special Tools
Oil Seal & Bearing Remover:
57001-1058
Steering Stem Nut Wrench:
57001-1100
Hook Wrench R37.5, R42:
57001-1101
Bearing Driver Set:
57001-1129
Fork Outer Tube Weight:
57001-1218
Jack:
57001-1238
Bearing Remover Shaft, 9:
57001-1265
Bearing Remover Head, 15 × 17:
57001-1267
Fork Piston Rod Puller, M12 × 1.25:
57001-1289
Fork Oil Level Gauge:
57001-1290
Special Tools
Fork Cylinder Holder:
57001-1413
Fork Oil Seal Driver, 48:
57001-1509
Fork Cylinder Holder:
57001-1573
Front Fork
The standard air pressure in the front fork legs is atmospheric pressure. Air pressure in the fork legs increase with normal use, so the fork action stiffens during operation. Release air pressure from the fork legs prior to each race through the pressure relief screw located in each front fork cap.
•
Place the jack under the frame so that the front wheel off the ground.
Special Tool - Jack: 57001-1238
•
Remove the screws [A] at the top of the front fork top plugs to let the air pressure equalize.
NOTE
○
Do not use the side stand when adjusting the air pressure.
○
Adjust the air pressure when the front forks are cold.
•
Inspect the O-ring of the screw. Replace the O-ring with a new one if damage.
•
Install the screw.
•
Place the jack under the frame so that the front wheel off the ground.
Special Tool - Jack: 57001-1238
•
To adjust rebound damping, turn the adjuster [A] on the front fork top plugs with the blade of a screwdriver until you feel a click. Adjust the rebound damping to suit you preference under special condition.
NOTE
○
The left and right fork legs must have the same shock damping.
Seated positions: adjuster turned fully clockwise [A].
Rebound Damping Adjuster Setting
Standard:
KX125-M1:
KX125-M2
∼
:
KX250-M1:
KX250-M2
∼
:
13 clicks
14 clicks
13 clicks
14 clicks
Front Fork
•
Place the jack under the frame so that the front wheel off the ground.
•
Special Tool - Jack: 57001-1238
Clean the bottom of the fork tubes.
•
Remove the caps on the bottom of the fork tubes.
•
To adjust compression damping, turn the adjuster [A] on the front fork cylinder valve with the blade of a screwdriver until you feel a click. Adjust the compression damping to suit your preference under special condition.
NOTE
○
The left and right fork legs must have the same shock damping.
Seated positions adjuster turned fully clockwise [A].
•
Put the caps into the bottom of the fork tubes.
Compression Damping Adjuster Setting
Standard:
KX125-M1: 14 clicks
KX125-M2
∼
: 10 clicks
KX250-M1: 13 clicks
KX250-M2
∼
: 10 clicks
•
Raise the front wheel off the ground using a jack.
Special Tool - Jack: 57001-1238
•
Remove:
Front Fender
Brake Hose Guard [A]
Brake Hose Clamps [B]
Fork Protectors [C]
Number Plate
Handlebar
•
For KX125/250-M2 model
∼
; note the following.
○
Raise the front wheel off the ground using a jack.
Special Tool - Jack: 57001-1238
○
Remove:
Front Fender
Brake Hose Clamps [A]
Fork Protectors [B] and Fork Guides
Number Plate
Handlebar
Front Fork
•
•
Loosen the upper fork clamp bolts.
Remove the front fork top plugs from the outer tube.
•
Slowly compress the front fork fully by pushing up the inner tubes [A] until their stepped portion contacts the dust seals [B] on the lower end of the outer tubes [C].
•
For KX125/250-M2 model
∼
; as shown in the figure.
•
Place a stand or other suitable support [A] under the front wheel.
•
For KX125/250-M2 model
∼
; as shown in the figure.
•
While holding the piston rod nut with a 17 mm (0.67 in.) wrench [A], loosen the front fork top plug [B] on the top of the piston rod.
•
Remove the fork top plug with the fork spring seat [C] and fork spring [D].
•
Remove the other fork spring in the same way as described above.
Front Fork
•
For KX125/250-M2 model; note the following.
○
While holding the piston rod nut with a 19 mm (0.75 in.) wrench [A], loosen the front fork top plug [B] on the top of the piston rod.
○
Remove the fork top plug with the fork spring seat [C] and fork spring [D].
○
Remove the other fork spring in the same way as described above.
•
Use the oil level gauge to measure the fork oil level.
○
With the fork fully compressed, put the oil level gauge [A] and the stopper [B], and adjust the distance from the top of the inner tube to oil.
Special Tool - Fork Oil Level Gauge: 57001-1290
Front Fork Oil Level (fully compressed, without spring)
Standard:
KX125-M1:
KX125-M2
∼
:
133
∼
137 mm (5.24
∼
5.39 in.)
103
∼
107 mm (4.00
∼
4.21 in.)
KX250-M1:
KX250-M2
∼
:
123
∼
127 mm (4.84
∼
5.00 in.)
86
∼
90 mm (3.39
∼
3.54 in.)
Adjustable Range:
KX125/250-M1: 100
∼
145 mm (3.94
∼
5.71 in.)
KX125/250-M2
∼
: 70
∼
120 mm (2.76
∼
4.72 in.)
If no oil is drawn out, there is insufficient oil in the fork tube. Pour in enough oil, then pump out the excess oil.
Recommended Fork Oil: KHL15-10 (KAYABA 01) or equivalent
•
Install the piston rod puller [A] onto the piston rod [B].
Special Tool - Fork Piston Rod Puller, M12 × 1.25: 57001
•
-1289
Slowly pull up the piston rod.
•
Let the fork oil overflow through the hole in the piston rod until it stops.
•
Insert the fork spring [A] into the fork tube.
•
Remove the piston rod puller.
Front Fork
•
Install the fork spring seat [A] on the fork spring [B].
•
Check both top plug O-ring [C] for damage and replace them if necessary.
•
For KX125/250-M2 model
∼
; as shown in the figure.
•
While holding the piston rod nut [A] with a 17 mm (0.67
in.) wrench [B], tighten the top plug [C] against the piston rod.
•
For KX125/250-M2 model
∼
; while holding the piston rod nut [A] with a 19 mm (0.75 in.) wrench [B], tighten the top plug [C] against the piston rod.
•
Tighten the fork top plug.
Torque - Piston Rod Nut: 28 N·m (2.9 kgf·m, 21 ft·lb)
Front Fork Top Plug: 29 N·m (3.0 kgf·m, 22 ft·lb)
•
Assemble the other fork tube in the same way as described above.
•
Tighten the upper fork clamp bolts.
Torque - Front Fork Clamp Blots (Upper): 20 N·m (2.0
kgf·m, 14.5 ft·lb)
NOTE
○
Tighten the two clamp bolts alternately two times to ensure even tightening torque.
•
Install the parts removed.
Front Fork
•
Refer to the Front Fork Oil Change/Oil Level Adjustment in the Periodic Maintenance chapter.
•
Remove the fork protectors [A] and hose guard [B].
•
Remove the front brake hose clamps [C].
•
Remove the front wheel (see Front Wheel Removal in the
Wheels/Tires chapter).
•
Remove the caliper [D] from the fork leg to be removed, and rest the caliper on some kind of stand so that it doesn’t dangle.
•
For KX125/250-M2 model; note the following.
○
Remove the fork protectors [A].
○
Remove the front brake hose clamps [B].
○
Remove the front wheel (see Front Wheel Removal in the
Wheels/Tires chapter).
○
Remove the caliper [C] from the fork leg to be removed, and rest the caliper on some kind of stand so that it doesn’t dangle.
•
•
Remove the number plate.
•
Loosen the upper and lower fork clamp bolts [A].
With a twisting motion, work the fork leg down and out.
•
If the fork leg was disassembled, check the fork oil level.
•
Install the fork so that the distance [B] between the top end [A] of the outer tube and the upper surface [C] of the steering stem head is specified dimension.
[B] = 15 mm (0.59 in.)
•
Route the cables and hose according to the Cable, Wire and Hose Routing section in the Appendix chapter.
•
Install the front wheel (see Front Wheel Removal in the
Wheels/Tires chapter).
•
Tighten the fork clamp bolts.
Torque - Front Fork Clamp Bolts (Upper, Lower): 20 N·m
(2.0 kgf·m, 14.5 ft·lb)
NOTE
○
Tighten the two clamp bolts alternately two times to ensure even tightening torque.
•
Tighten:
Torque - Front Caliper Mounting Bolts: 25 N·m (2.5 kgf·m,
18 ft·lb)
•
Check the front brake operation after installation.
Front Fork
Spring Guide Removal
•
Place the handlebar on one side, and loosen the each fork top plug.
•
Remove the front fork.
•
Hold the inner tube lower end in a vise.
•
Remove the top plug from the outer tube.
•
Push the outer tube all the way down away from the top plug and hold it there through out the following procedure.
○
For KX125/250-M1 model, pull the fork spring [A] away from the top plug a little and slip the spanner wrench [B] on the top of the spring seat and put it on the piston rod nut [C].
•
Use the wrenches on the rod nut and top plug [A] to loosen the piston rod nut.
•
Remove the top plug from the piston rod.
•
Lift the fork spring [B] and its top spring seat [C] out of the outer tube.
•
For KX125/250-M2 model
∼
; as shown in the figure.
•
Take the rebound damping adjuster rod [A] out of the piston rod.
Front Fork
•
Hold the fork tube [A] upside down over a clean container
[B] and pump it to drain the oil.
NOTE
○
To discharge the fork oil, pump the piston rod up [C] and down ten times.
•
Remove the piston rod nut [A] and the spring guide [B].
•
•
Cylinder Unit Removal (KX125/250-M1)
Clean the bottom of the inner tube.
•
Remove the cap on the bottom of the inner tube.
•
Hold the front fork horizontally in a vise.
Stop the cylinder unit [A] from turning by using the fork cylinder holder [B]. Unscrew the cylinder valve assembly
[C], and take the cylinder valve assembly and gasket out of the bottom of the inner tube.
Special Tool - Fork Cylinder Holder: 57001-1413
A. Inner Tube
B. Cylinder Valve Assembly
C. O-ring
D. Gasket
•
Pull the cylinder unit [A] out of the top of the inner tube.
NOTE
○
Do not disassembly the cylinder unit as the piston rod and cylinder are consisted of as the single assembly.
Front Fork
Cylinder Unit Removal (KX125/250-M2
∼
)
•
Using the spanner wrenchs [A], loosen the guide stay nut
[B].
•
Remove the snap ring [A].
•
Remove the O-ring [B], the guide stay nut [C], the stopper
[D] and the piston holder [E].
•
Clean the bottom of the inner tube.
•
Remove the cap on the bottom of the inner tube.
•
Hold he front fork horizontally in a vise.
•
Stop the cylinder unit [A] from turning by using the fork cylinder holder [B]. Unscrew the cylinder valve assembly
[C], and take the cylinder valve assembly and gasket out of the bottom of the inner tube.
Special Tool - Fork Cylinder Holder: 57001-1573
A. Inner Tube
B. Cylinder Valve Assembly
C. O-ring
D. Gasket
•
Pull the cylinder unit [A] out of the top of the inner tube
[B].
Front Fork
CAUTION
Do not disassemble the air chamber [A] by removing the spring [B] because the sealed air into the cylinder unit may be leaked.
•
Pull the piston rod assembly [A] out of the bottom of the cylinder unit [B].
Inner Tube Removal
•
Separate the inner tube [A] from the outer tube [B] as follows:
○
Slide up the spring band [C].
○
Slide up the dust seal [D].
○
Remove the retaining ring [A] from the outer tube.
○
Grasp the outer tube and stroke the inner tube up and down several times. The shock to fork seal separates the inner tube from the outer tube.
If the tubes are tight, use a fork outer tube weight [A].
Special Tool - Fork Outer Tube Weight: 57001-1218
Front Fork
•
Remove the guide bushes [A], washer [B], oil seal [C], retaining ring [D], and dust seal [E] from the inner tube.
•
For KX125/250-M2 model
∼
; remove the guide bushes
[A], collar [B], oil seal [C], retaining ring [D], and dust seal
[E] from the inner tube.
Inner to Outer Tube Assembly
•
Replace the following with new ones:
Dust Seal [A]
Retaining Ring [B]
Oil Seal [C]
Guide Bushes [D]
•
Place an oil coated plastic bag [E] over the end of the inner tube to protect the oil seals.
○
The inner tube guide bush groove has a sharp edge [F] that cut out the sealing lip of the seals as they are pushed down over the inner tube.
•
Install in order these parts on the inner tube.
•
When assembling the new outer tube guide bush [A], hold the washer against the new one, and tap the washer with the fork oil seal driver [B] until it stops.
Special Tool - Fork Oil Seal Driver, 48: 57001-1509
•
After installing the washer, install the oil seal by using the fork oil seal driver.
•
Special Tool - Fork Oil Seal Driver, 48: 57001-1509
Install the retaining ring to the outer tube.
•
Push the dust seal into the outer tube, and put the spring band on the dust seal.
Front Fork
•
Install Inner Cylinder (KX125/250-M1)
Install the cylinder unit.
•
Check the O-ring [A] on the cylinder valve assembly [B], and replace it with a new one.
•
Replace the gasket [C] with a new one.
•
Apply a non-permanent locking agent to the threads [D] of the cylinder valve assembly and screw the valve assembly into the bottom of the inner tube.
•
Hold the cylinder unit with the fork cylinder holder, and tighten the cylinder valve assembly.
Special Tool - Fork Cylinder Holder: 57001-1413
Torque - Front Fork Cylinder Valve Assembly: 54 N·m (5.5
kgf·m, 40 ft·lb)
•
Install Inner Cylinder (KX125/250-M2
∼
)
Install the cylinder unit.
•
Check the O-ring [A] on the cylinder valve assembly [B], and replace it with a new one.
•
Replace the gasket [C] with a new one.
•
Apply a non-permanent locking agent to the threads [D] of the cylinder valve assembly and screw the valve assembly into the bottom of the inner tube.
•
Hold the cylinder unit with the fork cylinder holder, and tighten the cylinder valve assembly.
Special Tool - Fork Cylinder Holder: 57001-1573
Torque - Cylinder Valve Assembly: 54 N·m (5.5 kgf·m, 40 ft·lb)
•
Check the O-ring [A] on the guide stay nut, and replace it with a new one if damaged.
•
Install the inner cylinder unit.
•
Install the piston holder [A] into the piston rod assembly
[B], then the stopper [C], so that its notch side downward to the piston holder.
•
Install the snap ring [D] in the groove of the piston rod assembly.
•
Fastening the top end of the piston holder to the snap ring and tighten the guide stay nut [E] to the piston holder.
Torque - Guide Stay Nut: 27 N·m (2.8 kgf·m, 20 ft·lb)
NOTE
○
Be sure to install securely a snap ring to fasten the stopper on the piston rod.
○
If it is not securely installed, the fork may be damaged.
Front Fork
•
Install the spring guide [A] so that the thinner portion end
[B] is down.
•
Screw on the piston rod nut [C] fully.
•
For KX125/250-M2
∼
; as shown in the figure.
•
Insert the rebound damping adjuster rod [A] into the piston rod.
•
Pour in the type and amount of fork oil specified and adjust the oil level (see Oil Level Adjustment).
•
Screw the fork piston rod puller [A] onto the end of the piston rod.
Special Tool - Fork Piston Rod Puller, M12 x 1.25: 57001
-1289
•
Pull the piston rod up with the special tool for the next procedures.
○
Pull up the piston rod slowly so as not to spill the fork oil out of the fork tube.
•
Install the fork spring [A].
•
Pull the fork spring away a little and slip the fork spring holder on the top of the spring seat and put it on the piston rod nut .
Front Fork
•
Remove the fork piston rod puller.
•
Check the O-ring [A] on the top plug and replace it with a new one if damaged.
•
Unscrew the rebound damping adjuster fully, then screw the front fork top plug onto the piston rod.
•
Holding the top plug [B] with a wrench, tighten the piston rod nut [C] against the top plug.
Torque - Piston Rod Nut: 28 N·m (2.9 kgf·m, 21 ft·lb)
•
For KX125/250-M2 model
∼
; as shown in the figure.
•
Pull out the fork spring holder, raise the outer tube and screw the top plug into it.
•
After installing the front fork, tighten the top plug.
Torque - Fork Top Plug: 29 N·m (3.0 kgf·m, 22 ft·lb)
•
Visually inspect the inner tube [A], repair any damage.
•
Nick or rust damage can sometimes be repaired by using a wet-stone to remove sharp edges or raised areas which cause seal damage.
If the damage is not repairable, replace the inner tube.
Since damage to the inner tube damages the oil seal, replace the oil seal whenever the inner tube is repaired or replaced.
•
Temporarily assemble the inner and outer tubes, and pump them back and forth manually to check for smooth operation.
CAUTION
If the inner tube is badly bent or creased, replace it.
Excessive bending, followed by subsequent straightening, can weaken the inner tube.
Front Fork
•
Visually inspect the guide bushes [A], and replace them if necessary.
•
Inspect the dust seal [A] for any signs of deterioration or damage.
Replace it if necessary.
•
Replace the oil seal [B] with a new one whenever it has been removed.
•
Since a spring becomes shorter as it weakens, check its free length [A] to determine its condition.
If the spring of either fork leg is shorter than the service limit, it must be replaced. If the length of a replacement spring and that of the remaining spring vary greatly, the remaining spring should also be replaced in order to keep the fork legs balanced from motorcycle stability.
Fork Spring Free Length
Standard: 460 mm (18.11 in.)
Service Limit: 450 mm (17.72 in.)
Rear Suspension (Uni-Trak)
Rear Shock Absorber:
The rear suspension system of this motorcycle is Uni-trak.
It consists of a rear shock absorber, swing arm, tie-rod and rocker arm.
To suit to various riding conditions, the spring preload of the shock absorber can be adjusted or the spring can be replaced with an optional one. Also the damping force can be adjusted easily so changing oil viscosity unnecessary.
•
Turn the rebound damping adjuster [A] on the rear shock absorber lower end with the blade of a screwdriver until you feel a click.
If the damper setting feels too soft or too stiff, adjust it in accordance with the following table:
•
For KX125/250-M2 model
∼
; as shown in the figure.
[A]: Rebound Damping Adjuster
Seated position: adjuster turned fully clockwise [A].
Rebound Damping Adjuster Setting
Standard:
KX125-M1: 12 clicks
KX125-M2
∼
: 11 clicks
KX250: 10 clicks
NOTE
○
Adjustment of the rebound damping adjuster for the rear suspension will slightly affect the compression damping force. Always make any damping adjustments in small steps and test their effects before using them in competition.
Rear Suspension (Uni-Trak)
•
Turn the compression damping adjuster [A] on the rear shock absorber gas reservoir with a flat-head screwdriver.
If the damping feels too soft or too stiff, adjust it in accordance with the following table.
Seated position: adjuster turned fully clockwise [A].
Compression Damping
Standard:
KX125: 13 clicks
KX250-M1: 12 clicks
KX250-M2
∼
: 10 clicks
NOTE
○
Adjustment of the rebound damping adjuster for the rear suspension will slightly affect the compression damping force. Always make any damping adjustments in small steps and test their effects before using them in competition.
•
Remove:
Seat
Side Covers
Muffler
Rear Frame Mounting Bolts [A]
Rear Frame [B] with Air Cleaner Housing
•
Using the jack under the frame, raise the rear wheel off the ground.
Special Tool - Jack: 57001-1238
•
Using the hook wrenches [A], loosen the locknut [B] on the rear shock absorber.
Special Tool - Hook Wrench R37.5, R42: 57001-1101
Rear Suspension (Uni-Trak)
•
Using the stem nut wrench [A], turn the adjusting nut [B] as required. Turning the adjusting nut downward marks the spring action harder and upward softer.
Special Tool - Steering Stem Nut Wrench: 57001-1100
Spring Preload Adjustment
(Adjusting nut position [A] from the center of the mounting hole)
Standard:
KX125-M1: 112 mm (4.41 in.)
KX125-M2
∼
: 111 mm (4.37 in.)
KX250-M1: 117 mm (4.61 in.)
KX250-M2
∼
: 112 mm (4.41 in.)
Adjustable Range
KX125:
109
∼
127.5 mm (4.29
∼
5.02 in.)
•
KX250: 109
∼
129.5 mm (4.29
∼
5.10 in.)
Tighten the locknut securely.
•
After adjusting, move the spring up and down to make sure that the spring is seated.
•
Install the parts removed.
•
Tighten the rear frame mounting bolts.
Torque - Rear Frame Mounting Bolts: 34 N·m (3.5 kgf·m 25 ft·lb)
•
Since the spring becomes shorter as it weakens, check its free length [A] to determine its condition.
If the spring of either rear shock absorber is shorter than the service limit, it must be replaced. If the length of replacement spring and that of the remaining spring vary greatly, the remaining spring should also be replaced in order to keep the rear shock absorbers balanced of motorcycle stability.
Shock Absorber Spring Free Length
Standard: 260 mm (10.24 in.)
Service Limit: 255 mm (10.04 in.)
•
Remove:
Seat
Side Covers
Muffler
Rear Frame with Air Cleaner Housing
•
Using the jack under the frame, raise the rear wheel off the ground.
Special Tool - Jack: 57001-1238
Rear Suspension (Uni-Trak)
•
Remove the tie-rod front mounting bolt [A].
CAUTION
When pulling out the mounting bolts, lift the rear wheel slightly. Forcing or tapping on a bolt could damage the bolt, sleeve, and bearing
•
Remove the rear shock absorber lower mounting bolt [B].
•
For KX125/250-M2 model
∼
; note the following.
○
Remove the tie-rod rear mounting bolt [A].
○
Remove the rear shock absorber lower mounting bolt [B].
•
Remove the rear shock absorber upper mounting bolt [A], nut, and pull out the rear shock absorber [B] down and out.
•
Pack the rocker arm needle bearings with grease.
•
Tighten the following:
Torque - Rear Shock Absorber Mounting Nut (Upper): 39
N·m (4.0 kgf·m, 29 ft·lb)
Rear Shock Absorber Mounting Nut (Lower): 34
N·m (3.5 kgf·m, 24 ft·lb)
Tie-Rod Mounting Nut: 83 N·m (8.5 kgf·m, 61 ft·lb)
Rear Frame Mounting Bolts: 34 N·m (3.5 kgf·m, 25 ft·lb)
In addition to the standard spring, heavy and light springs are available. If the standard spring is improper for your purpose, select a proper one according to the rider’s weight or course conditions.
•
Remove
Side Covers
Seat
Muffler
•
Rear Frame with Air Cleaner Housing
Remove the rear shock absorber.
•
Clean the threaded portion on the upper of the rear shock absorber.
•
Hold the lower of the rear shock absorber with a vise.
Rear Suspension (Uni-Trak)
•
Using the hook wrenches [C], loosen the locknut [B] and turn the adjusting nut [A] all way up.
Special Tool - Hook Wrench R37.5, R42: 57001-1101
•
•
Remove the rear shock absorber from the vise.
Slide down the rubber bumper [A].
•
Remove the spring guide [B] from the shock absorber and lift off the spring [C].
•
Exchange the spring for an optional part. Install the spring so that closed coil large diameter end [A] faces upward.
•
Install the spring guide.
•
Adjust the spring preload (see Spring Preload Adjust-
• ment).
•
Install the rear shock absorber.
Install the parts removed.
The oil should be changed in the rear shock absorber at least once per racing season. The frequency for best performance must be based upon riding conditions and rider ability.
•
Remove the rear shock absorber from the frame (see
Rear Shock Absorber Removal).
•
Remove the shock absorber spring (see Spring Replacement).
•
Point the valve [A] away from you. slowly release nitrogen gas pressure by pushing down the valve core with a screw driver.
WARNING
Do not to point the reservoir valve toward your face or body when releasing nitrogen gas pressure. An oil mist is often released with the nitrogen. Always release nitrogen gas pressure before disassembling the rear shock absorber to prevent explosive separation of parts.
Rear Suspension (Uni-Trak)
•
For KX125/250-M2 model
∼
; note the following.
○
Adjust the gas reservoir damping adjusters [A] to the softest position.
○
Remove the air bleeder bolt [B] and pump the rear shock to drain the oil out of the rear shock body.
○
Install the air bleeder bolt.
•
Using the suitable tool [A] and press, push the reservoir cap [B] in 10 mm (0.39 in.).
•
Remove the circlip [C] from the gas reservoir.
•
Pull the gas reservoir cap [B] out of the gas reservoir using the pliers [A].
•
Pry or tap [A] at the gaps [B] in the stop [C] with suitable tools to free the stop from the rear shock body [D].
•
Slide the stop up the top of the piston rod then lightly tap around the seal with a suitable rod and mallet, and push
• the seal assembly 10 mm (0.39 in.) down.
Remove the circlip [A].
•
Lightly move the piston rod back and forth, and pull out the piston rod assembly.
•
Pour the oil out of the rear shock body.
Rear Suspension (Uni-Trak)
•
Pour KYB K2-C (SAE 5W or Bel-Ray SE2 #40) oil into the gas reservoir to 60
∼
70 mm (2.63
∼
2.76 in.) [A] from the gas reservoir upper end.
•
Check that the bladder [A] on the gas reservoir cap is not partially collapsed.
If it is, push down the valve core with a screwdriver.
•
Check the bladder for sign of damage or crack.
If necessary, replace it with a new one.
CAUTION
Do not use a damaged or partially collapsed bladder, because it may burst, gently reducing rear shock performance. .
•
Apply grease to the lip [B] of the bladder and install the reservoir cap [C].
•
Push the bladder into the gas reservoir slowly until it just clears the circlip groove. Wipe out any spilled oil.
CAUTION
Ensure that no air remains in the system.
•
Check the circlip for weakening, deformity and flaws.
If necessary, replace it with a new one.
CAUTION
If weakened, deformed or flawed circlip is used, the gas reservoir cap may not hold when injecting the nitrogen gas. This would allow oil and internal parts to explode out of the reservoir.
•
Mount the circlip [A] in the groove in the gas reservoir.
Rear Suspension (Uni-Trak)
•
Pull up the gas reservoir cap [A] against the circlip. The end of the gas reservoir cap must align [C] with the end of the gas reservoir [B].
WARNING
If the end of the gas reservoir cap and the end of the gas reservoir are not aligned, the circlip is not correctly fitting in the groove in the gas reservoir or is deformed. In this case, the oil and internal parts could explode out of the reservoir when injecting the nitrogen gas or while riding the motorcycle.
•
Pour KYB K2-C (SAE 5W or Bel-Ray SE2 #40) oil into the rear shock body to 55 mm (1.77 in.) [A] from the lower end
[B] of the rear shock body.
•
Insert the piston end [A] of the piston rod assembly into the rear shock body [C] slowly. Do not insert the seal assembly [B] yet. Pump the piston rod until all the air is forced out of the rear shock body.
Rear Suspension (Uni-Trak)
•
Push the seal assembly into the rear shock body until it just clears the circlip groove.
•
Check the circlip.
If it is deformed or damaged, replace it with a new one.
•
Fit the circlip [A] into the groove in the rear shock body
[B].
CAUTION
If the circlip is not a certain fit in the groove in the rear shock body, the piston rod assembly may come out of the shock absorber when injecting the nitrogen gas or riding the motorcycle.
•
Pull up the piston rod assembly [C] against the circlip.
•
Force the stop [D] into the rear shock body by lightly tapping around the edge of the stop with a mallet.
•
Fully extend the piston rod assembly.
•
For KX125/250-M2 model
∼
; note the following.
○
Hold the lower end of the push rod assembly with a vise.
○
Pump the rear shock up and down several times, and then leave it in the fully extend position for about three minutes.
○
Remove the air bleeder bolt from the upper part of the rear shock body.
If oil comes out of the air bleeder bolt hole, let it overflow until it stops.
○
Install the suitable oil cup [A] to the air bleeder bolt hole, and fill the specified oil into the cup.
○
Purge the air from between the gas reservoir [B] and rear shock body [C] by slowly pumping the piston rod [D] in and out.
○
Install the air bleeder bolt securely.
○
Fully extend the piston rod assembly.
•
Inject nitrogen gas to a pressure of 50 kPa (0.5 kgf/cm²,
7 psi) through the valve on the gas reservoir.
•
Check the rear shock body and gas reservoir for oil and gas leaks.
If there are no leaks, inject the nitrogen gas up to the 980 kPa (10 kgf/cm², 142 psi) pressure.
WARNING
Pressurize the gas reservoir with nitrogen gas only.
Do not use air or other gases, since they may cause premature wear, rust, fire hazard or substandard performance.
High pressure gas is dangerous. Have a qualified mechanic perform this procedure.
•
•
Install the spring and spring guide.
•
Adjust spring preload. Reinstall the rear shock absorber.
Install the parts removed.
Rear Suspension (Uni-Trak)
WARNING
Since the reserve tank of the rear shock absorber contains nitrogen gas, do not incinerate the reserve tank without first releasing the gas or it may explode.
•
Remove the shock absorber (see Rear Shock Absorber
Removal).
•
Remove the valve cap [A] and release the nitrogen gas completely from the gas reservoir.
•
Remove the valve.
WARNING
Since the high pressure gas is dangerous, do not point the valve toward your face or body.
Swingarm
•
Place the jack under the frame so that the rear wheel is off the ground.
Special Tool - Jack: 57001-1238
•
Remove:
Rear Wheel (see Rear Wheel Removal in the
Wheels/Tires chapter)
Clamps [A]
Brake Pedal [B]
Tie-rod Rear Mounting Bolt [C]
Rear Shock Absorber [D] (see Rear Shock Absorber Removal)
•
For KX125/250-M2 model
∼
; note the following.
○
Remove:
Rear Wheel (see Rear Wheel Removal in the
Wheels/Tires chapter)
Rear Flap [A]
Clamps [B]
Brake Pedal [C]
Plug and Rocker Arm Pivot Nut [D]
CAUTION
When pulling out the mounting bolts, lift the rear wheel slightly. Forcing or tapping on a bolt could damage the bolt, sleeve, and bearing.
•
Pull out the swingarm pivot shaft [E], and remove the swingarm [F].
•
Separate the chain guide and chain slipper from the swing arm.
•
Apply plenty of grease to the inside of the needle bearings, sleeves, and oil seals.
•
Tighten the following:
Torque - Swingarm Pivot Shaft Nut: 98 N·m (10.0 kgf·m, 72 ft·lb)
Tie-Rod Mounting Nut: 83 N·m (8.5 kgf·m, 61 ft·lb)
•
Refer to the Wheels/Tires, Final Drive, and Brakes chapters for wheel installing.
Swingarm
•
Remove:
Swingarm
Collars [A]
Grease Seals [B]
Sleeves [C]
Needle Bearings [D]
•
Remove the needle bearings using the oil seal & bearing remove [E].
Special Tool - Oil Seal & Bearing Remover: 57001-1058
•
For KX125/250-M2 model
∼
; as shown in the figure.
•
Replace the needle bearings, grease seals and oil seals with new ones.
•
Apply plenty of grease to the grease seals, oil seals and needle bearings.
NOTE
○
Install the needle bearings so that the manufacturer’s marks face out.
○
Install the grease seals so that the deep groove side of the rip faces in-ward.
Special Tool - Bearing Driver Set: 57001-1129
•
Install the needle bearings [A], grease seals [B] and oil seals [C] position as shown.
○
The installation procedure is the same as the counter side.
•
For KX125/250-M2 model
∼
; as shown in the figure.
•
Refer to the Chain Guide and Chain Slipper Wear Inspection in the Periodic Maintenance chapter.
Tie-Rod, Rocker Arm
•
Using the jack under the frame, raise the rear wheel off the ground.
Special Tool - Jack: 57001-1238
•
Remove the tie-rod front mounting bolt [A].
CAUTION
When pulling out the mounting bolts, lift the rear wheel slightly. Forcing or tapping on a bolt could damage the bolt, sleeve, and bearing.
•
Remove the tie-rod rear mounting bolt [B], and then take out the tie-rods [C].
•
For KX125/250-M2 model
∼
; note the following.
○
Remove the tie-rod rear mounting bolt [A].
○
Remove the tie-rod front mounting bolt [B], and then take out tie-rod [C].
•
Apply plenty of grease to the inside of the needle bearings and oil seals.
•
Be sure seated the washers to the rocker arm mating surfaces.
•
Tighten the tie-rod front and rear mounting nuts.
Torque - Tie-Rod Mounting Nuts: 83 N·m (8.5 kgf·m, 61 ft·lb)
•
Using the jack under the frame, raise the rear wheel off the ground.
Special Tool - Jack: 57001-1238
•
Loosen the swingarm pivot shaft nut.
•
Remove the tie-rod front mounting bolt [A].
CAUTION
When pulling out the mounting bolts, lift the rear wheel slightly. Forcing or tapping on bolt could damage the bolt, sleeve, and bearing.
•
•
Remove the rear shock absorber lower mounting bolt [B].
•
Remove the rocker arm pivot shaft [C].
Remove the rocker arm [D].
Tie-Rod, Rocker Arm
•
For KX125/250-M2 model
∼
; note the following.
○
Remove the tie-rod rear mounting bolt [A].
○
Remove the rear shock absorber lower mounting bolt [B].
○
Remove the rocker arm pivot shaft [C] and then remove the rocker arm [D].
•
Apply plenty of grease to the inside of the rocker arm holes, needle bearings, oil seals and grease seals out-
• side of the sleeve.
Be sure seated washers.
•
Tighten the following:
Torque - Rocker Arm Pivot Nut: 83 N·m (8.5 kgf·m, 61 ft·lb)
Rear Shock Absorber Mounting Nut (Lower): 34
N·m (3.5 kgf·m, 24 ft·lb)
Tie-Rod Mounting Nut: 83 N·m (8.5 kgf·m, 61 ft·lb)
Swingarm Pivot Shaft Nut: 98 N·m (10.0 kgf·m, 72 ft·lb)
•
Remove:
Tie-Rod (see Tie-Rod Removal)
Rocker Arm (see Rocker Arm Removal)
Washers [A]
Sleeves [B]
Oil Seal [C]
Grease Seals [D]
•
Remove the needle bearings [E], using the bearing remover head and bearing remover shaft.
•
Remove the needle bearing [F], using the oil seal & bearing remover.
Tie-Rod, Rocker Arm
Special Tools - Bearing Remover Head, 15 × 17: 57001
-1267
Bearing Remover Shaft, 9: 57001-1265
Oil Seal & Bearing Remover: 57001-1058
•
For KX125/250-M2
∼
; as shown in the figure.
•
Replace the needle bearing, grease seals and oil seals with new ones.
•
Apply plenty of grease to the oil seal and needle bearings.
NOTE
○
Install the grease seals so that the deep groove side of the rip out-ward.
•
Install the needle bearing [A], [B], grease seals [C] and oil seals [D] position as shown.
•
Tighten the following:
Torque - Rocker Arm Pivot Nut: 83 N·m (8.5 kgf·m, 61 ft·lb)
Rear Shock Absorber Mounting Nut (Lower): 34
N·m (3.5 kgf·m, 24 ft·lb)
Tie-Rod Mounting Nut: 83 N·m (8.5 kgf·m, 61 ft·lb)
Swingarm Pivot Shaft Nut: 98 N·m (10.0 kgf·m, 72 ft·lb)
•
For KX125/250-M2 model
∼
; as shown in the figure.
If there is any doubt as to the condition of either needle bearing, replace the bearing and sleeve as a set.
Uni-Trak Maintenance
•
Refer to the Swingarm and Uni-Trak Linkage Inspection in the Periodic Maintenance chapter.
•
Pull out the sleeves [A] of the rocker arm, and measure the outside diameter of the sleeve.
If the sleeve is worn past the service limit, replace the sleeve.
Sleeve Outside Diameter
[Large]
Standard: 19.987
∼
20.000 mm (0.7869
∼
0.7874
in.)
19.85 mm (0.781 in.) Service Limit:
[Small]
Standard:
Service Limit:
15.987
∼
16.000 mm (0.6294
∼
0.6299
in.)
15.85 mm (0.624 in.)
A bent bolt causes vibration, poor handling, and instability.
•
To measure the bolt runout, remove the bolt, place it in V blocks, and set a dial gauge to the bolt at a point halfway between the blocks. Turn [A] the bolt to measure the runout. The amount of dial variation is the amount of runout.
If runout exceeds the service limit, replace the bolt.
Bolt Runout
Standard: TIR 0.1 mm (0.004 in.) or less
Service Limit: TIR 0.2 mm (0.008 in.)
Table of Contents
Handlebar Installation (KX125-M1
M2)...............................................
Handlebar Installation (KX125M6F
)...............................................................................
13
Exploded View
Exploded View
No.
Fastener
1 Handlebar Holder Bolts
2 Steering Stem Head Nut
3 Steering Stem Locknut
4 Front Fork Clamp Bolts (Upper, Lower)
N·m
25
98
4.9
20
Torque kgf·m
2.5
10.0
0.5
2.0
5. Handlebar Holder (Upper)
6. Handlebar
7. Handlebar Holder (Lower)
8. Steering Stem Head Bracket
9. Tapered Roller Bearing
10. Head Pipe
11. Tapered Roller Bearing
12. Steering Stem
13. Pad
AD: Apply adhesive cement
G: Apply grease.
O: Apply 2 Stroke Oil
T: Tighten all snugly, then loosen, retighten to 4.9 N·m (0.5 kgf·m, 43 in·lb).
A: KX125-M1
∼
M3 Model
B: KX125M6F Model
∼
ft·lb
18
72
43 in·lb
14.5
Remarks
T
Special Tools
Steering Stem Bearing Driver:
57001-137
Head Pipe Outer Race Driver, 54.5:
57001-1077
Steering Stem Bearing Driver Adapter, 34.5:
57001-1074
Steering Stem Nut Wrench:
57001-1100
Head Pipe Outer Race Press Shaft:
57001-1075
Head Pipe Outer Race Remover ID > 37 mm:
57001-1107
Head Pipe Outer Race Driver, 51.5:
57001-1076
Jack:
57001-1238
Steering
•
Refer to the Steering Inspection in the Periodic Maintenance chapter.
•
Refer to the Steering Inspection in the Periodic Maintenance chapter.
•
Remove:
Front Wheel (see Front Wheel Removal in the
Wheels/Tires chapter)
Brake Hose Clamp
Caliper Mounting Bolts (see Caliper Removal in the
Brakes chapter)
Master Cylinder Clamp (see Front Master Cylinder Removal in the Brakes chapter)
Front Fender
Handlebar (see Handlebar Removal)
Front Fork (see Front Fork Removal in the Suspension chapter)
•
•
Remove the steering stem head nut and washer.
Remove the steering stem head.
•
Pushing up on the stem base [A], and remove the steering stem locknut [B] with the steering stem nut wrench [C], then remove the steering stem [D] and stem base.
Special Tool - Steering Stem Nut Wrench: 57001-1100
•
Take off the upper stem bearing inner race (tapered roller bearing) [A].
•
Drive out the bearing outer races from the head pipe.
○
Remove the outer races pressed into the head pipe, using the head pipe outer race remover [A], and hammer the head pipe outer race remover to drive it out.
Special Tool - Head Pipe Outer Race Remover: 57001
-1107
NOTE
○
If either steering stem bearing is damaged, it is recommended that both the upper and lower bearing (including outer races) should be replaced with new ones.
Steering
•
Remove the lower stem bearing inner rase (tapered roller bearing) [A] with its grease seal from the stem using suitable tools.
•
Replace the bearing outer race with new ones.
○
Apply grease to the outer races, and drive them into the head pipe at the same time using the head pipe outer race press shaft [A] and the drivers.
Special Tools - Head Pipe Outer Race Press Shaft: 57001
-1075
Head Pipe Outer Race Driver, 51.5: 57001
-1076 [B]
Head Pipe Outer Race Driver, 54.5: 57001
-1077 [C]
•
Replace the lower inner races with new ones.
○
Apply grease to the lower tapered roller bearing [A], and drive it onto the stem using the steering stem bearing driver [B] and adapter [C].
Special Tools - Steering Stem Bearing Driver: 57001-137
Steering Stem Bearing Driver Adapter,
34.5: 57001-1074
•
Apply grease to the upper inner race, and install it in the head pipe.
•
Install the stem through the head pipe and upper bearing, install the stem cap and hand-tighten the locknut while pushing up on the stem base.
•
Install the stem head and washer, and tighten the stem head nut lightly.
Steering
•
Settle the bearing in place as follows;
○
Tighten the stem locknut to 39 N·m (4.0 kgf·m, 29 ft·lb) of torque. (To tighten the steering stem locknut to the specified torque, hook the wrench [A] on the stem locknut, and pull the wrench at the hole by 22.2 kg force [B] in the direction shown.)
Special Tool - Steering Stem Nut Wrench: 57001-1100
○
Check that there is no play and the steering stem turns smoothly without rattles. If not, the steering stem bearings may be damaged.
○
Again back out the stem locknut a fraction of a turn until it turns lightly.
○
Turn the stem locknut lightly clockwise until it just becomes hard to turn. Do not overtighten, or the steering will be too tight.
•
Tighten:
Torque - Steering Stem Locknut: 4.9 N·m (0.5 kgf·m, 43 in·lb)
•
Install the front fork (see Front Fork Installation in the Suspension chapter).
NOTE
○
Tighten the fork upper clamp bolts first, next the stem head nut, last the fork lower clamp bolt.
Torque - Steering Stem Head Nut: 98 N·m (10.0 kgf·m, 72 ft·lb)
Front Fork Clamp Bolts:
Upper: 20 N·m (2.0 kgf·m, 14.5 ft·lb)
Lower: 20 N·m (2.0 kgf·m, 14.5 ft·lb)
NOTE
○
Tighten the two clamp bolts alternately two times to ensure even tightening torque.
•
Install the parts removed (see the appropriate chapter).
WARNING
Do not impede the handlebar turning by routing the cables, wires and hoses improperly (see the Appendix chapter).
•
Check and Adjust:
Steering
Front Brake
Clutch Cable
Throttle Cable
Steering Maintenance
•
Refer to the Steering Stem Bearing Lubrication in the Periodic Maintenance chapter.
•
Using a high-flash point solvent, wash the upper and lower tapered rollers in the cages, and wipe the upper and lower outer races, which are press-fitted into the frame head pipe, clean off grease and dirt.
•
Visually check the outer rase and the rollers.
Replace the bearing assembly if it show damage.
•
Whenever the steering stem is removed, or if the steering cannot be adjusted for smooth action, inspect the steering stem for straightness.
If the steering stem shaft is bent [A], replace the steering stem.
Handlebar
•
Remove:
Clutch Holder [A]
Engine Stop Switch [B]
Clamp [C] (Discard)
Left Handlebar Grip [D]
•
Remove:
Throttle Grip Assy [A]
Master Cylinder [B] (see Front Master Cylinder Removal in the Brakes chapter)
KX125-M1
∼
M3/KX250-M1
∼
M2;
•
Remove:
Handlebar Holder Bolts [A]
Handlebar Holder (Upper) [B]
Handlebar [C]
Number Plate [D]
KX125M6F
∼
;
•
Remove:
Number Plate [A]
Pad [B]
•
Remove:
Handlebar Holder Bolts [A]
Handlebar Holders (Upper) [B]
Handlebar [C]
Handlebar
∼
∼
•
Apply adhesive cement to the inside of the left handlebar grip.
•
Install the left handlebar grip so that the triangle mark [A] on the grip point to the punch mark [B] on the handlebar.
•
Install the clutch holder so that the parting line [C] of the holder align with the punch mark [D] on the handlebar.
•
Apply grease to the throttle cable upper end and clutch cable upper end.
•
Apply a 2 stroke engine oil to the throttle grip inner wall
[A].
•
Install the throttle grip assembly so that the grip [A] is in as far as it will go.
○
Position the throttle grip assembly so that the horizontal parting line [B] of the throttle case align with the punch mark [C] on the handlebar.
○
Install the master cylinder so that the vertical parting line [D] of the front master cylinder clamps align with the punch mark [E] on the handlebar.
•
Install the handlebar [A] on the handlebar holder (lower) as shown.
Same Length [B]
Bridge Bar [C]
•
Install the handlebar holder (upper).
○
Mount the handlebar holder (upper) [A] so that the cut side
[B] on the holder points toward the front.
○
First tighten the rear holder bolts [C], then, tighten the front holder bolts [D]. After tightening the bolts, a clearance will be created forward the holder.
•
Tighten the handlebar holder bolts [C].
Torque - Handlebar Holder Bolts: 25 N·m (2.5 kgf·m, 18 ft·lb)
Handlebar
∼
•
Apply adhesive cement to the inside of the left handlebar grip.
•
Install the left handlebar grip and clutch holder as shown.
180 mm (7.09 in.) [A]
Frame Horizontal Line [B]
15°
∼
25° [C]
20°
∼
30° [D]
Arrow Mark [E]
Front [F]
•
Apply grease to the throttle cable upper end and clutch cable upper end.
•
Apply a 2 stroke engine oil to the throttle grip inner wall
[A].
•
Install the throttle grip assembly so that the grip [A] is in as far as it will go.
185 mm (7.28 in.) [B]
○
Position the throttle grip assembly so that the horizontal parting line [C] of the throttle case is parallel with the frame horizontal line [D] as shown.
○
Install the master cylinder so that the reserve tank cap align [E] with the frame horizontal line as shown.
•
Install the handlebar [A] on the handlebar holder (lower) as shown.
Same Length [B]
Bridge Bar [C]
Protrusion of Graduation [D]
•
Install the handlebar holder (upper) [A] with the handlebar.
○
Tighten the front and rear bolts [B] of the handlebar holders equally.
If the handlebar holders are correctly installed, there will be same amount of gap [C] on the front and rear side of the holder after the bolts tightening.
Torque - Handlebar Holder Bolts: 25 N·m (2.5 kgf·m, 18 ft·lb)
•
Install:
Pad
Number Plate
Table of Contents
14
Wiring Diagram
KX125M:
Wiring Diagram
KX250M:
Exploded View
KX125/250:
Exploded View
No Fastener
1 Flywheel Bolt (KX125)
2 Flywheel Nut (KX250)
3 Stator Plate Mounting Screw
4 Spark Plug
5
Magneto Cover Bolts (KX125/250-M1)
Magneto Cover Bolts (KX125/250-M2
∼
)
6 C.D.I Unit Mounting Bolts
7 Ignition Coil Mounting Bolts
8. Magneto Cover
9. Flywheel Magneto
10. Stator
11. Ignition Coil
12. C.D.I Unit
13. Spark Plug Cap
14. Main Harness (KX250)
15. Regulator/Rectifier (KX250)
16. Fuel Cut Valve (KX250)
17. Throttle Sensor (KX250)
SS: Apply silicon sealant.
A: KX125/250-M2 Model
∼
B: KX125-M1
∼
M2 Model
C: KX125-M3 Model
∼
27
4.9
3.9
8.8
8.8
N·m
22
78
4.4
Torque kgf·m
2.2
8.0
0.45
2.8
0.5
0.4
0.9
0.9
ft·lb
16
58
39 in·lb
20
43 in·lb
35 in·lb
78 in·lb
78 in·lb
Remarks
Specifications
Item
Magneto
Crankshaft Sensor Air Gap:
KX125-M1
∼
M6F
KX125M7F
∼
KX250
Crankshaft Sensor Resistance
Magneto Output Voltage
Magneto Coil Resistance
Regulator/Rectifier (KX250):
0.45
0.65
0.45
180
∼
∼
∼
∼
Standard
0.85 mm (0.018
1.05 mm (0.026
0.85 mm (0.018
280 Ω in the text in the text
∼
∼
∼
0.033 in.)
0.041 in.)
0.033 in.)
Internal Resistance
Out Put Voltage
Ignition System
Ignition Timing:
KX125 13° BTDC @9 710 r/min (rpm)
KX250 (Disconnect the throttle sensor lead) 14° BTDC @7 740 r/min (rpm)
Ignition Coil:
3 Needle Arcing Distance 7 mm (0.26 in.) or more
Primary Winding Resistance:
KX125-M1
∼
M3
KX125M6F
∼
KX250
Secondary Winding Resistance:
KX125-M1
∼
M3
KX125M6F
∼
KX250 in the text
14.7 ±0.5 V
0.24 ±0.04 Ω (at 20°C)
0.33 ±0.05 Ω (at 20°C)
0.53 ±0.08 Ω (at 20°C)
8.3 ±1.2 kΩ (at 20°C)
9.0 ±1.4 Ω (at 20°C)
12.6 ±1.9 kΩ (at 20°C)
Spark Plug:
Type:
KX125-M1
KX125-M2
∼
M3
KX125M6F
∼
KX250
Gap
C.D.I. Unit
Noise Suppressor Resistance
Throttle Sensor: (KX250)
NGK BR9EIX
NGK R6918B-9
NGK BR9ECMVX
NGK BR8EIX
0.7
∼
0.8 mm (0.026
∼
0.031 in.) in the text
3.75
∼
6.25 Ω
Input Voltage around 5 V
Output Voltage:
(when the throttle valve completely closed).
0.4
∼
0.6 V
(when the throttle fully opened).
3.5
∼
3.7 V
Fuel Cut Valve: (KX250)
Resistance 49.7
∼
56.2 Ω
Protrusion:
When Battery is Disconnected
When Battery is Connected
19.4
∼
19.6 mm (0.76
∼
0.77 in.)
21.3
∼
21.7 mm (0.84
∼
0.85 in.)
Special Tools
Spark Plug Wrench, Hex 21:
57001-110
Flywheel Puller, M12 × 1.75:
57001-252
Hand Tester:
57001-1394
Peak Voltage Adapter:
57001-1415
Flywheel & Pulley Holder:
57001-1605
Precautions
There are numbers of important precautions that are musts when servicing electrical systems. Learn and observe all the rules below.
○
The electrical parts should never be struck sharply, as with a hammer, or allowed to fall on a hard surface. Such a shock to the parts can damage them.
○
Troubles may involve one or in some cases all items.
Never replace a defective part without determining what
CAUSED the failure. If the failure was caused by some other item or items, they too must be repaired or replaced, or the new replacement will soon fail again.
○
Make sure all connectors in the circuit are clean and tight, and examine leads for signs of burning, fraying, etc. Poor leads and bad connections will affect electrical system operation.
○
Measure coil and winding resistance when the part is cold
(at room temperature).
○
Electrical Connectors
[A] Connectors
[B] Connectors
Safety Instructions:
WARNING
The ignition system produces extremely high voltage. Do not touch the spark plug, ignition coil, or high tension lead while the engine is running, or you could receive a severe electrical shock.
Electrical Wiring
•
Visually inspect the wiring for signs of burning, fraying, etc.
If any wiring is poor, replace the damaged wiring.
•
Pull each connector [A] apart and inspect it for corrosion, dirt, and damage.
If the connector is corroded or dirty, clean it carefully. If it
• is damaged, replace it.
Check the wiring for continuity.
○
Use the wiring diagram to find the ends of the lead which is suspected of being a problem.
○
Connect an ohmmeter between the ends of the leads.
○
Set the meter to the x 1 Ω range, and lead the meter.
If the meter does not read 0 Ω the lead is defective. Replace the lead or the wiring harness if necessary.
Ignition Timing
•
Remove the magneto cover.
•
Check to see if the center mark of the three marks [A] on the magneto stator is aligned with the mark [B] on the crankcase.
If the marks are not aligned, loosen the magneto stator screws [C] and turn the magneto stator [D].
•
Tighten the screws securely.
Torque - Stator Plate Mounting Screws: 4.4 N·m (0.45
•
kgf·m, 39 in·lb)
Install the magneto cover.
•
Tighten:
Torque - Magneto Cover Bolts:
4.9 N·m (0.5 kgf·m, 43 in·lb) (KX125/250-M1)
3.9 N·m (0.4 kgf·m, 35 in·lb) (KX125/250-M2
∼
)
The ignition timing can be adjusted for different power
• band to suit to rider’s preference ability.
Remove the magneto cover.
•
Loosen the stator screws.
•
Adjust the timing by shifting the stator position within the three lines [A].
Ignition Timing
NOTE
○
For best engine performance, it is very important to adjust the ignition timing within the adjustable range just explained.
Crankshaft Rotation [A]
Stator Movement [B]
Retard [C]
Advance [D]
•
Tighten the stator screws securely.
Torque - Starter Plate Mounting Screws: 4.4 N·m (0.45
•
kgf·m, 39 in·lb)
Install the magneto cover.
•
Tighten:
Torque - Magneto Cover Bolts:
4.9 N·m (0.5 kgf·m, 43 in·lb) (KX125/250-M1)
3.9 N·m (0.4 kgf·m, 35 in·lb) (KX125/250-M2
∼
)
•
Test ride the motorcycle and readjust the ignition timing if necessary.
Flywheel Magneto
•
Remove the magneto cover.
•
Hold the flywheel steady with the flywheel holder [A], and remove the flywheel bolt (KX125) or nut (KX250) [B].
Special Tool - Flywheel & Pulley Holder: 57001-1605
•
Remove the flywheel holder.
•
Screw the flywheel puller [A] into the flywheel by turning it counterclockwise (left-hand thread).
•
Remove the flywheel from the crankshaft by turning in the puller center bolt and tapping the head of the bolt lightly with a hammer, while holding the puller body steady.
There is a woodruff key in the crankshaft tapered portion.
Special Tool - Flywheel Puller, M12 × 1.75: 57001-252
CAUTION
Never strike the grab bar or the flywheel itself. Striking the bar can bend it. If the flywheel is strike, the magnets may lose their magnetism.
•
Unscrew the mounting screws [A], and remove the stator plate [B] and the wiring grommet [C].
•
Remove the band.
•
KX125:
Remove the number plate.
•
Disconnect the magneto lead connector [A] from the C.D.I
unit.
Flywheel Magneto
•
KX250:
Remove the left radiator shroud.
•
Disconnect the magneto lead connector [A] from the main harness.
•
Using a high-flash point solvent, clean off any oil or dirt that may be on the crankshaft taper [A] or in the hole [B] of the flywheel. Dry them with a clean cloth.
•
Fit the woodruff key [A] securely in the slot of the crankshaft before installing the stator plate.
•
Apply silicone sealant around the circumference of the wiring grommet.
•
Set the stator wiring grommet [A] securely in the notch [B] of the left crankshaft half, and route the wires according to the Cable, Wire and Hose Routing section in the Appendix chapter.
•
Install the stator plate and tighten it.
Torque - Stator Plate Mounting Screws: 4.4 N·m (0.45
kgf·m, 39 in·lb)
•
Holding the flywheel steady, with the flywheel holder, and tighten the flywheel bolt (KX125) or nut (KX250).
Special Tool - Flywheel & Pulley Holder: 57001-1605
Torque - Flywheel Bolt (KX125): 22 N·m (2.2 kgf·m, 16 ft·lb)
Flywheel Nut (KX250): 78 N·m (8.0 kgf·m, 58 ft·lb)
Flywheel Magneto
•
Measure the crankshaft sensor air gap [A] (Clearance between the flywheel and the crankshaft sensor [B] core.)
Crankshaft Sensor Air Gap
Standard:
KX125-M1
∼
M6F 0.45
∼
0.85 mm (0.018
∼
0.033 in.)
KX125M7F
∼
0.65
∼
1.05 mm (0.026
∼
0.041 in.)
KX250 0.45
∼
0.85 mm (0.018
∼
0.033 in.)
•
If the gap is incorrect, adjust it (see this chapter).
Replace the gasket with a new one.
•
Connect the magneto lead connector to the C.D.I. unit
(KX125) or main harness (KX250).
•
There are three types of magneto problems: short, open
(wire burned out), or loss in flywheel magnetism. A short or open in one of the coil wires will result in either a low output, or no output at all. A loss in flywheel magnetism, which may be caused by dropping or hitting the flywheel by leaving it near an electromagnetic field, or just by aging, will result in low output.
•
Inspect the magneto output voltage, and do the following procedures.
○
Disconnect the magneto lead connector [A].
Flywheel Magneto
○
Connect the auxiliary leads between the C.D.I unit [A]
(KX125) or main harness connector [A] (KX250) and the magneto lead connector [B].
○
Connect the hand tester as shown in the table 1.
○
Start the engine.
○
Run it at the rpm given in the table 1.
○
Note the voltage readings (total 2 measurements).
Table 1 Magneto Output Voltage
(1) KX125
Tester
Range
250 V AC
Connections
Tester (+) to Tester (–) to
Reading
@4 000 rpm
White lead Red lead 80 V or more
(2) KX250
Tester
Range
250V AC
50 V AC
Connections
Tester (+) to
Reading
Tester (–) to @ 4 000 rpm
White lead Red lead 59 V or more
Yellow/White lead
Yellow lead 16 V or more
If the output voltage shows the value in the table, the magneto operates properly.
If the output voltage shows a much higher than the value in the table, the regulator/rectifier is damaged. A much lower reading than that given in the table indicates that
• the magneto is defective.
To check the stator coil resistance as follows.
○
Stop the engine.
○
Disconnect the auxiliary leads.
○
Connect the hand tester as shown in the table 2.
○
Note the readings (total 2 measurement).
(1) KX125
Tester
Range x 1Ω
Connections
Tester (+) to
White lead
Tester (–) to
Red lead
(2) KX250
Tester
Range
× 1Ω
Connections
Tester (+) to Tester (–) to
White lead Red lead
Yellow/White lead Yellow lead
Reading
10
∼
30 Ω
Reading
10
∼
30 Ω
1
∼
4Ω
Flywheel Magneto
If there is more resistance than shown in the table, or no hand tester reading (infinity) the stator has an open lead and must be replaced. Much less than this resistance means the stator is shorted, and must be replaced.
•
Using the highest resistance range of the hand tester, measure the resistance between each leads and chassis ground.
Any hand tester reading less than infinity (∞) indicates a short, necessitating stator replacement.
If the stator coils have normal resistance, but the voltage check showed the magneto to be defective; then the rotor magnets have probably weakened, and the flywheel must be replaced.
Special Tool - Hand Tester: 57001-1394
•
Remove:
Left Radiator Shroud
•
Band [A]
Disconnect the regulator/rectifier lead connector [B].
•
Unscrew the mounting bolt, and remove the regulator/rectifier [C].
•
Warm up the engine to obtain actual magneto operating conditions.
•
Stop the engine, and disconnect the regulator/rectifier lead connector.
•
Using an auxiliary leads, connect the regulator/rectifier connector [A] and main harness connector [B].
•
Connect the hand tester [C] as shown in the table.
•
Start the engine, and note the voltage readings at various engine speeds. The readings should show under the specified voltage when the engine speed is low and, as the engine speed rises, the readings should also rise.
Flywheel Magneto
Regulator/Rectifier Output Voltage
Connections
Tester Range Reading
Tester (+) Tester (–) to
25 V DC Red/White Black/Yellow 14.2
∼
15.2 V
•
Push off the stop switch to stop the engine, and disconnect the hand tester.
If the regulator/rectifier output voltage is kept between the values given in the table, the charging system is considered to be working normally.
If the output voltage is much higher than the values specified in the table, the regulator/rectifier is defective or the regulator/rectifier leads are loose or open.
If the output voltage does not rise as the engine speed increases, then the regulator/rectifier is defective or the magneto output is insufficient for the loads. Check the magneto and regulator/rectifier to determine which part is defective.
•
Remove the regulator/rectifier.
•
Set the hand tester x 100 Ω range, measure the internal resistance in both directions between the terminals.
Special Tool - Hand Tester: 57001-1394
If the reading is not specified value, replace the regulator/rectifier.
Internal Resistance Unit: Ω
(–)*
Terminal
R/W
Y
Y/W
BK/Y
Tester (+) Lead
R/W Y Y/W
300
∼
3K 200
∼
20K 200
∼
20K
BK/Y
–
500
∼
5K
500
∼
5K 500
∼
5K 300
∼
3K
–
500
∼
5K 500
∼
50K
500
∼
50K 500
∼
5K
– 500
∼
5K
–
(–)*: Tester (–) Lead
CAUTION
Use only Hand Tester 57001-1394 for this test. An ohmmeter other than the Hand Tester may show different readings. If a megger or a meter with a large-capacity battery is used, the regulator will be damaged.
Ignition System
WARNING
The ignition system produces extremely high voltage. Do not touch the spark plug, ignition coil, or high tension lead while the engine is running, or you could receive a severe electrical shock.
•
Remove:
Seat
Radiator Shrouds
•
Fuel Tank
Disconnect the ignition coil primary lead [A].
•
Pull the plug cap [B] off the spark plug.
•
Unscrew the mounting bolts [C], and remove the ignition coil [D].
Measuring arcing distance
The most accurate test for determining the condition of the ignition coil is made by measuring arcing distance using
• the coil tester for the 3-needle method.
Remove the ignition coil.
•
Connect the ignition coil (with the spark plug cap left installed on the high tension lead) [A] to the tester [B], and measure the arcing distance.
WARNING
To avoid extremely high voltage shocks, do not touch the coil or lead.
If the distance reading is less than the specified value, the ignition coil or spark plug cap is defective.
3 Needle Arcing Distance
Standard: 7 mm (0.26 in.) or more
•
To determine which part is defective, measure the arcing distance again with the spark plug cap removed from the ignition coil lead.
If the arcing distance is subnormal as before, the trouble is with the ignition coil itself. If the arcing distance is now normal, the trouble is with the spark plug cap.
Ignition System
Measuring Coil Resistance
If the arcing tester is not available, the coil can be checked for a broken or badly shorted winding with an ohmmeter. However, an ohmmeter cannot detect layer shorts and shorts resulting from insulation breakdown
• under high voltage.
Remove the ignition coil.
•
Measure the primary winding resistance [A].
○
Connect an ohmmeter between the coil terminals.
○
Set the meter to the x 1 Ω range, and read the meter.
•
Measure the secondary winding resistance [B].
○
Pull the spark plug cap off the lead.
○
Connect an ohmmeter between the high tension lead and the ground lead terminal.
○
Set the meter to the x 1 kΩ range, and read the meter.
If the meter does not read as specified, replace the coil.
If the meter reads as specified, the ignition coil windings are probably good. However, if the ignition system still does not perform as it should after all other components have been checked, test replace the coil with one known to be good.
Ignition Coil Winding Resistance
Primary windings:
KX125-M1
∼
M3
KX125M6F
∼
0.24 ±0.04 Ω (at 20°C)
0.33 ±0.05 Ω (at 20°C)
KX250 0.53 ±0.08 Ω (at 20°C)
Secondary windings:
KX125-M1
∼
M3 8.3 ±1.2 kΩ (at 20°C)
KX125M6F
∼
9.0 ±1.4 kΩ (at 20°C)
KX250 12.6 ±1.9 kΩ (at 20°C)
Special Tool - Hand Tester: 57001-1394
•
Check the high tension lead for visible damage.
If the spark high tension is damaged, replace the coil.
•
Refer to the Spark Plug Cleaning and Inspection in the
Periodic Maintenance chapter.
•
Refer to the Spark Plug Gap Inspection in the Periodic
Maintenance chapter.
•
Remove the number plate.
•
Disconnect the magneto lead connector [A] (KX125) or main harness connector (KX250).
•
Unscrew the mounting bolt [B] and remove the C.D.I Unit
[C].
Ignition System
CAUTION
When inspecting the C.D.I. unit observe the following to avoid damage to the C.D.I. unit.
Do not disconnect the C.D.I. unit while the engine is running.
This may damage the C.D.I. unit.
Ignition Coil Primary Peak Voltage Check
•
Disconnect the spark plug cap from mounting the spark plug.
•
Connect the good spark plug [A] to the spark plug cap, then touch the engine with the spark plug.
NOTE
○
Measure the voltage with each lead connected correctly.
The correct value may not be obtained if disconnected.
○
Maintain the correct value of compression pressure for the cylinder. (Be sure to measure the voltage with the spark plug install to the cylinder head.)
○
The correct value may not be obtained if disconnected.
•
Connect the peak voltage adapter [B] between the terminal of primary lead (orange) and ground connection of the unit with the lead of the ignition coil [C] connected.
Special Tool: Peak Voltage Adapter: 57001-1415
Type: KEK-54-9-B
Hand Tester: 57001-1394
Connection: Tester Positive → Ground Lead [D]
Tester Negative →Orange Lead [E]
C.D.I Unit [F]
•
Shift the gear to the neutral position, then free the engine stop switch.
•
Crank the engine by kicking the pedal several times to measure the peak voltage of the primary ignition coil.
Primary Voltage:
KX125-M1
∼
M3: 200 V or above
KX125M6F
∼
160 V or above
KX250 150 V or above
WARNING
Do not touch the metal portion of the probe in case of measuring the voltage, or you may receive a serious electric shock.
If the voltage is less than the specified value, see the next page.
Ignition System
Ignition System
•
Crankshaft Sensor Peak Voltage Check
To check the peak voltage, do the following procedures.
○
Disconnect the connector of the magneto lead connector from the C.D.I. unit (KX125), or the main harness
(KX250).
NOTE
○
Measure the voltage with each lead connected correctly.
The correct value may not be obtained if disconnected.
○
Maintain the correct value of compression pressure for the cylinder (Be sure to measure the voltage with the spark plug installed to the cylinder head).
○
The correct value may not be obtained if disconnected.
○
Connect the peak voltage adapter [A] of the tester to the terminals of the magneto lead connector [B].
Special Tool: Peak Voltage Adapter: 57001-1415
Type: KEK-54-9-B
Connection:
Hand Tester: 57001-1394
Adapter Positive → Green/White Lead
[C]
Adapter Negative → White/Yellow
Lead [D]
○
Crank the engine by kicking the pedal several times to measure the peak voltage of the crankshaft sensor.
Peak Voltage:
KX125-M1
∼
M3: 2.4 V or above
KX125M6F
∼
1.6 V or above
KX250 1.6 V or above
WARNING
Do not touch the metal portion of the probe in case of measuring the voltage, or you may receive a serious electric shock.
If the voltage is less than the specified, check the crankshaft sensor.
Ignition System
Exciter Coil Peak Voltage Check
•
Disconnect the connector of the magneto lead connector from the C.D.I. unit (KX125), or the main harness
(KX250).
•
To check the peak voltage, do the following procedures.
NOTE
○
Measure the voltage with each lead connected correctly.
The correct value may not be obtained if disconnected.
○
Maintain the correct value of compression pressure for the cylinder (Be sure to measure the voltage with the spark plug installed to the cylinder head).
○
The correct value may not be obtained if disconnected.
○
Connect the peak voltage adapter [A] of the tester to the terminals of the magneto lead connector [B].
Special: Peak Voltage Adapter: 57001-1415
Type: KEK-54-9-B
Hand Tester: 57001-1394
Connection: Adapter Positive → White Lead [C]
Adapter Negative → Red Lead [D]
○
Crank the engine by kicking the pedal several times to measure the peak voltage of the exciter coil.
Peak Voltage:
KX125:
KX250:
32 V or above
16 V or above
If the voltage is less than the specified, check the exciter coil.
•
Fuel Cut Valve Operation Check: (KX250)
Disconnect the carburetor lead connector [A].
•
Set the tester to the DC25V range, and connect it to the carburetor lead of the main harness side.
Connections:
Tester Positive → Red/White Lead [B]
Tester Negative → Brown Lead [C]
•
Special Tool - Hand Tester: 57001-1394
•
Start the engine.
Run it at the rpm given below.
Fuel Cut Valve Operate Revolutions
Standard: 8 100 rpm
•
Read the tester, running the engine at the specified revolution.
Fuel Cut Valve Operation Voltage:
When engine is specified revolutions or above: DC 12 V
When engine is less than specified revolutions: 0 V
If the tester does not read as specified, check the magneto.
If the magneto has normal functions, replace the C.D.I.
Unit.
Ignition System
NOTE
○
If the variable rheostat is available, refer to throttle sensor inspection.
•
Remove the carburetor lead connector.
•
Connect the auxiliary leads [A] between carburetor lead connector [B] and main harness connector [C].
•
Set the tester to the DC 10V range, and connect it to the auxiliary leads.
Special Tool - Hand Tester: 57001-1394
Hand Tester (+) → Red/Green Lead
•
Hand Tester (–) → Black/Green Lead
•
Start the engine.
Check the sensor input voltage with the engine running.
Throttle Sensor Input Voltage
Standard: 4 V or above
If it is not within the specified voltage range, check the magneto output voltage. If it has normal functions, replace the C.D.I. Unit.
•
To check the output voltage, do the following procedures.
○
Using the auxiliary leads [A], connect the hand tester [B] as follows.
Hand Tester (+) → White/Black Lead
Hand Tester (–) → Black/Green Lead
○
Remove the spark plug.
○
Crank the engine by kicking the pedal several times to measure the throttle sensor output voltage with the throttle valve completely closed.
Throttle Sensor Output Voltage
Standard:
0.4
∼
0.6 V (when throttle valve is completely closed.)
If it is not within the specified voltage range, adjust the throttle sensor position (see Throttle Sensor Position Adjustment).
If it is within specified voltage, go to next test.
○
Crank the engine by kicking the pedal several times to measure the throttle sensor output voltage with the throttle fully opened.
Throttle Sensor Output Voltage
(when the throttle fully opened)
Standard: 3.5
∼
3.7 V
If it is not within the specified voltage, replace the throttle sensor.
•
Disconnect the engine stop switch lead.
•
Start the engine.
•
Ground the stop switch lead of the main harness side while the engine is running.
If does not stop the engine, replace the C.D.I Unit.
Ignition System
•
Remove:
Magneto Lead Connector (see Flywheel Magneto Inspection).
•
Set the hand tester [A] to the × 100Ω range and connect it to the Green/White [B] and White/Yellow [C] Leads in the connector.
Special Tool - Hand Tester: 57001-1394
If there is more resistance than the specified value, the coil has an open lead and must be replaced. Much less than this resistance means the coil is shorted, and must be replaced.
Crankshaft Sensor
180
∼
280 Ω
Resistance:
•
Using the highest resistance range of the tester, measure the resistance between the crankshaft sensor leads and chassis ground.
Any tester reading less than infinity (∞) indicates a short, necessities replacement of the crankshaft sensor assembly.
•
Loosen the crankshaft sensor screws [A].
•
Insert the thickness gauge [B] between the crankshaft sensor core and the timing plat.
Thickness Gauge [B]
Standard:
KX125-M1
∼
KX125M6F
KX125M7F
∼
0.65 mm (0.026 in.)
0.85 mm (0.033 in.)
KX250-M1
∼
M2 0.65 mm (0.026 in.)
•
While pressing the crankshaft sensor toward the magneto flywheel, tighten the coil screws and remove the thickness gauge.
•
Check the air gap (see Flywheel Magneto Installation).
If the air gap is not within the specified range, readjust the gap.
Throttle Sensor
NOTE
○
If the variable rheostat is not available, refer to throttle sensor output/input voltage check in the C.D.I Unit inspection.
○
When inspecting the throttle sensor the throttle valve of the carburetor shall be completely closed and remain the throttle cable connected.
•
Remove the carburetor (see Fuel System chapter).
•
Connect the carburetor lead connector [A] with the battery
[B], variable rheostat [C] and hand testers [D] as shown.
Variable Rheostat (+) → R/G Lead Terminal [E]
Hand Tester (+) → W/BK Lead terminal [F]
Hand Tester (–) → BK/G Lead terminal [G]
•
Check the sensor input voltage.
Throttle Sensor Input Voltage
Standard: around 5 V
•
Check the sensor output voltage with the throttle valve is completely closed.
Throttle Sensor Output Voltage
Standard:
0.4
∼
0.6 V (when the throttle valve completely closed.)
If it is not within the specified voltage, adjust the throttle sensor position (see Throttle Sensor Position Adjustment).
If it is within specified voltage, go to next test.
•
Check the sensor output voltage with the throttle fully opened.
Throttle sensor Output Voltage
Standard: 3.5
∼
3.7 V (When throttle fully opened.)
If it is not within the specified voltage, replace the sensor.
•
•
Remove the carburetor.
•
Check the throttle valve is completely closed.
•
Loosen the throttle sensor mounting bolt [A].
Connect the carburetor lead connector with the battery, variable rheostat and handtesters in the same manner as specified in the throttle sensor Inspection.
•
Adjust the position of the sensor until the output voltage is within the specified voltage range.
Throttle Sensor Output Voltage
Standard:
0.4
∼
0.6 V (when throttle valve is completely closed.)
•
If it is not within the specified voltage range, replace the sensor.
Fuel Cut Valve
WARNING
Gasoline is extremely flammable and can be explosive under certain conditions. Turn the ignition switch OFF. Do not smoke. Make sure the area is well-ventilated and free from any source of flame or sparks; this includes any appliance with a pilot light.
•
•
Disconnect the carburetor lead connector.
Remove the carburetor.
•
Drain the fuel from the float bowl removing the drain plug.
After draining, install the drain plug securely.
•
Loosen the fuel cut valve [A] and remove it.
•
Installation is reverse of removal.
•
Remove the fuel cut valve [A].
•
Connect and disconnect one 12 V battery [B] to the carburetor lead connector as shown. The valve rod moves.
If the protrusion exceeds the standard (too long or too short), the valve is defective and must be replaced.
Testing Fuel Cut Valve
Standard Protrusion:
19.4
∼
19.6 mm (0.76
∼
0.77 in.) (when battery is disconnected)
21.3
∼
21.7 mm (0.84
∼
0.85 in.) (when battery is connected )
Table of Contents
15
Troubleshooting Guide
NOTE
○
This is not an exhaustive list, giving every possible cause for each problem listed. It is meant simply as a rough guide to assist the troubleshooting for some of the more common difficulties.
Engine Doesn’t Start, Starting
Difficulty:
Engine won’t turn over:
Cylinder, piston seizure
Crankshaft seizure
Connecting rod small end seizure
Connecting rod big end seizure
Transmission gear or bearing seizure
Kick shaft return spring broken
Kick ratchet gear not engaging
No fuel flow:
No fuel in tank
Fuel tap turned off
Tank cap air vent obstructed
Fuel tap clogged
Fuel line clogged
Float valve clogged
Fuel cut valve left close
Engine flooded:
Float level too high
Float valve worn or stuck open
Starting technique faulty
(when flooded, kick with the throttle fully open to allow more air to reach the engine.)
No spark; spark weak:
Spark plug dirty, broken, or maladjusted
Spark plug cap or high tension wiring trouble
Spark plug cap not in good contact
Spark plug incorrect
C.D.I Unit trouble
Ignition coil trouble
Ignition coil resistor open
Flywheel magneto damaged
Wiring shorted or open
Fuel/air mixture incorrect:
Idle adjusting screw maladjusted
Slow jet or air passage clogged
Air cleaner clogged, poorly sealed, or missing
Starter jet clogged
Compression Low:
Spark plug loose
Cylinder head not sufficiently tightened down
Cylinder, piston worn
Piston ring bad (worn, weak, broken, or sticking)
Piston ring/groove clearance excessive
Cylinder head gasket damaged
Cylinder head warped
Cylinder base gasket damaged
Read valve damaged
Cylinder nut loose
Poor Running at Low Speed:
Spark weak:
Spark plug dirty, broken, or maladjusted
Spark plug cap or high tension wiring trouble
Spark plug cap shorted or not in good contact
Spark plug incorrect
C.D.I Unit trouble
Ignition coil trouble
Flywheel magneto damaged
Ignition coil lead or C.D.I Unit lead not in good contact
Fuel/air mixture incorrect:
Idle adjusting screw maladjusted
Slow jet or air passage clogged
Air cleaner clogged, poorly sealed, or missing
Choke plunger stuck open
Float level too high or too low
Fuel tank air vent obstructed
Fuel cut valve won’t fully open
Carburetor holder loose
Air cleaner duct loose
Compression Low:
Spark plug loose
Cylinder head not sufficiently tightened down
Cylinder, piston worn
Piston ring bad (worn, weak, broken, or sticking)
Piston ring/groove clearance excessive
Cylinder head gasket damaged
Cylinder head warped
Cylinder base gasket damaged
Reed valve damaged
Cylinder nut loose
Kips ports stuck open:
KIPS exhaust valve stuck open (valve seizure, or carbon accumulation)
KIPS exhaust valves assembled incorrectly
Exhaust advancer spring damaged
Exhaust valve operating rod seizure
Rod (for KIPS) seized in cylinder
Other:
C.D.I Unit trouble
Transmission oil viscosity too high
Brake dragging
Troubleshooting Guide
Poor Running or No Power at High
Speed:
Firing incorrect:
Spark plug dirty, damaged, or maladjusted
Spark plug cap or high tension wiring damaged
Spark plug cap shorted or not in good contact
Spark plug incorrect
C.D.I Unit trouble
Ignition coil trouble
Flywheel magneto damaged
Ignition coil lead or C.D.I Unit lead not in good contact
Fuel/air mixture incorrect:
Main jet clogged or wrong size
Jet needle or needle jet worn
Jet needle clip in wrong position
Float level too high or too low
Fuel cut valve won’t fully open
Air jet or air passage clogged
Air cleaner clogged, poorly sealed, or missing
Choke plunger stuck open
Fuel to carburetor insufficient
Water or foreign matter in fuel
Fuel tank air vent obstructed
Carburetor holder loose
Air cleaner duct loose
Fuel tap clogged
Fuel line clogged
Compression low:
Spark plug loose
Cylinder head not sufficiently tightened down
Cylinder, piston worn
Piston ring bad (worn, weak, broken, or sticking)
Piston ring/and clearance excessive
Cylinder head gasket damaged
Cylinder head warped
Cylinder base gasket damaged
Reed valve damaged
Cylinder nut loose
Engine rpm will not rise properly:
Choke plunger stuck open
Float level too high or too low
Main jet clogged
Throttle valve does not fully open
Air cleaner clogged
Muffler clogged
Water or foreign matter in fuel
Cylinder exhaust port clogged
Brake dragging
Clutch slipping
Overheating
Transmission oil level too high
Transmission oil viscosity too high
Crankshaft bearing worn or damaged
KIPS ports stuck closed:
KIPS ports stuck closed
KIPS exhaust valves stuck closed (valve seizure, or carbon accumulation)
KIPS exhaust valves assembled incorrectly
KIPS ports clogged (carbon accumulation)
Exhaust valve operating rod seizure
Rod (for KIPS) seized in cylinder
Knocking:
Carbon built up in combustion chamber
Fuel poor quality or incorrect
Spark plug incorrect
C.D.I Unit trouble
Overheating:
Firing incorrect:
Spark plug dirty, broken, or maladjusted
Spark plug incorrect
C.D.I Unit trouble
Fuel/air mixture incorrect:
Main jet clogged or wrong size
Fuel level in carburetor float bowl too low
Fuel cut valve won’t fully open
Carburetor holder loose
Air cleaner poorly sealed, or missing
Air cleaner duct poorly sealed
Air cleaner clogged
Compression high:
Carbon built up in combustion chamber
Engine load faulty:
Brake dragging
Clutch slipping
Transmission oil level too high
Transmission oil viscosity too high
Lubrication inadequate:
Transmission oil level too low
Transmission oil poor quality or incorrect
Coolant incorrect:
Coolant level too low
Coolant deteriorated
Cooling system component incorrect:
Radiator clogged
Radiator cap trouble
Water pump not rotating
Clutch Operation Faulty:
Clutch slipping:
No clutch lever play
Clutch cable maladjusted
Clutch inner cable catching
Friction plate worn or warped
Steel plate worn or warped
Clutch spring broken or weak
Clutch release mechanism trouble
Clutch hub or housing unevenly worn
Troubleshooting Guide
Clutch not disengaging properly:
Clutch lever play excessive
Clutch plate warped or too rough
Clutch spring tension uneven
Transmission oil deteriorated
Transmission viscosity too high
Transmission oil level too high
Clutch housing frozen on drive shaft
Clutch release mechanism trouble
Gear Shifting Faulty:
Doesn’t into gear; shift pedal doesn’t return:
Clutch not disengaging
Shift fork bent or seized
Gear stuck on the shaft
Gear positioning lever binding
Shift return spring weak or broken
Shift return spring pin loose
Shift mechanism arm spring broken
Shift mechanism arm broken
Shift drum broken
Jumps out of gear:
Shift fork worn
Gear groove worn
Gear dogs and/or dog holes worn
Shift drum groove worn
Gear positioning lever spring weak or broken
Shift fork guide pin worn
Drive shaft, output shaft, and/or gear splines worn
Overshifts:
Gear positioning lever spring weak or broken
Shift mechanism arm spring broken
Abnormal Engine Noise:
Knocking:
C.D.I Unit trouble
Carbon built up in combustion chamber
Fuel poor quality or incorrect
Spark plug incorrect
Overheating
Piston slap:
Cylinder/piston clearance excessive
Cylinder, piston worn
Connecting rod bent
Piston pin, piston pin hole worn
Other noise:
Connecting rod small end clearance excessive
Connecting rod big end clearance excessive
Piston ring worn, broken or stuck
Piston seizure or damaged
Cylinder head gasket leaking
Exhaust pipe leaking at cylinder head connection
Crankshaft runout excessive
Engine mounts loose
Crankshaft bearing worn
Primary gear worn or chipped
Abnormal Drive Train Noise
Clutch noise:
Clutch housing/friction plate clearance excessive
Clutch housing gear/primary gear backlash excessive
Metal chip jammed in clutch housing gear teeth
Transmission noise:
Crankcase bearing worn or damaged
Transmission gear worn or chipped
Metal chip jammed in gear teeth
Transmission oil insufficient or too thin
Kick ratchet gear not properly disengaging from kick gear
Output shaft idle gear worn or chipped
Drive chain noise:
Drive chain adjusted improperly
Chain worn
Rear and/or engine sprocket(s) worn
Chain lubrication insufficient
Rear wheel misaligned
Abnormal Frame Noise:
Front fork noise:
Oil insufficient or too thin
Spring weak or broken
Front fork air pressure high
Rear shock absorber noise:
Shock absorber damaged
Disc brake noise:
Pad installed incorrectly
Pad surface glazed
Disc warped
Caliper trouble
Cylinder damaged
Other noise
Bracket, nut, bolt, etc.
not properly mounted or tightened
Exhaust Smoke:
Excessive white smoke:
Throttle cable maladjusted
Brownish smoke:
Air cleaner clogged
Main jet too large of fallen out
Starter plunger stuck open
Float level too high
Troubleshooting Guide
Handling and/or Stability
Unsatisfactory:
Handlebar hard to turn:
Control Cable routing incorrect
Wiring routing incorrect
Steering stem locknut too tight
Bearing ball damaged
Bearing race dented or worn
Steering stem bearing lubrication inadequate
Steering stem bent
Tire air pressure too low
Handlebar shakes or excessively vibrates:
Tire worn
Swingarm sleeve or needle bearing damaged
Rim warped, or not balanced
Front, rear axle runout excessive
Wheel bearing worn
Handlebar clamp loose
Steering stem head nut loose
Handlebar pulls to one side:
Frame bent
Wheel misalignment
Swingarm bent or twisted
Swingarm pivot shaft runout excessive
Steering maladjusted
Steering stem bent
Front fork leg bent
Right/left front fork oil level uneven
Shock absorption unsatisfactory:
(Too hard)
Front fork oil excessive
Front fork oil viscosity too high
Front fork leg bent
Front fork air pressure high
Tire air pressure too high
Rear shock absorber maladjusted
(Too soft)
Front fork oil insufficient and/or leaking
Front fork oil viscosity too low
Front fork, rear shock absorber spring weak
Rear shock absorber gas leaking
Rear shock absorber maladjusted
Brake Doesn’t Hold:
Disc brake:
Air in the brake line
Pad or disc worn
Brake fluid leak
Disc warped
Contaminated pads
Brake fluid deteriorated
Primary or secondary cup damaged
Master cylinder scratched inside
Brake maladjustment (lever or pedal play excessive)
Cable, Wire and Hose Routing
KX125:
Cable, Wire and Hose Routing
1. Throttle Cable
2. Clutch Cable
3. Engine Stop Switch Lead
4. Band
5. Radiator Overflow Tube
6. Right Screen
7. Run the overflow tube backward of the down tube.
8. Run the overflow tube outside of the engine mount bracket.
9. Run the overflow tube forward of the radiator connection hose.
10. Left Screen
11. Frame
12. C.D.I. Unit
13. Run the throttle cable left side of the stop switch lead.
14. Clamp the magneto lead (harness) and stop switch lead connector. Do not clamp the throttle cable.
15. Run the magneto lead (Harness) through the frame and radiator.
16. Magneto Lead (Harness)
17. Band (Clamp the magneto lead and air vent tube)
18. Magneto
19. Ignition Coil
20. Ignition Coil Primary Winding Lead
21. Tighten together with ignition coil ground lead and magneto ground lead (harness) as figure.
22. Ignition Coil Ground Lead
23. Air Vent Hose
24. Clamp the clutch cable.
25. To the C.D.I. Unit
26. Clamps (Install the magneto lead from this side)
27. To the Ignition coil
28. To the Magneto
29. Mating section on the clamp at outside. (KX125-M2
∼
)
30. Run the clutch cable above the number plate mounting bracket. (KX125M6F
∼
)
A: KX125-M3
∼
Model
B: KX125-M1
∼
M3 Model
C: KX125M6F
∼
Model
Cable, Wire and Hose Routing
KX250:
Cable, Wire and Hose Routing
1. Throttle Cable
2. Clutch Cable
3. Engine Stop Switch Lead
4. Band
5. Radiator Overflow Tube
6. Right Screen
7. Run the overflow tube backward of the down tube
8. Run the overflow tube outside of the engine mount bracket
9. Run the overflow tube forward of the radiator connection pipe.
10. Left Screen
11. Frame
12. C.D.I. Unit
13. Run the throttle cable leftside of main harness.
14. Clamp the main harness and stop switch lead connector.
15. Regulator/Rectifier
16. Do not clamp the throttle cable.
17. Bands
18. Main Harness
19. Magneto Lead Connector
20. Ignition Coil
21. Ignition Coil Primary Winding Lead
22. Ignition Coil Ground Lead
23. Tighten together with the ignition coil ground lead and magneto ground lead (harness).
24. Carburetor Lead Connector
25. Carburetor
26. Magneto
27. Clamp the clutch cable
28. Clamp the magneto lead
29. Install the spark plug cap so that the high tension lead and spark plug cap do not touch the water hose.
30. Run the clutch cable through the clamps.
31. Mating section on the clamp at outside. (KX250-M2
∼
)
Cable, Wire and Hose Routing
KX125:
Cable, Wire and Hose Routing
1. Clamps
2. Left Radiator
3. Right Radiator
4. To the steering stem hole.
5. Air Vent Hose
6. To the fuel tank cap
7. Radiator Overflow Tube
8. Run the radiator overflow tube outside of the engine mount bracket
9. Carburetor
10. Clamp
11. Run the air vent hoses and overflow tube through the clamp.
12. Air Vent Hoses
13. Over Flow Tube
14. Water Hose
15. Install the fuel hose between the vent hoses.
16. Run the radiator overflow tube between frame and right radiator.
17. Pay attention to inflection of the radiator overflow tube.
18. Do not face the pinch head of the clamp to the air cleaner duct side.
19. Air Cleaner Duct Side
A: KX125-M1
∼
M3 Model
B: KX125M6F
∼
Model
Cable, Wire and Hose Routing
KX125M6F
∼
:
1. Run the high tension lead inside of the radiator bracket.
2. Tighten together with ignition coil ground lead and magneto ground lead (harness) as figure.
3. Ignition Coil
4. Ignition Coil Ground Lead
5. Magneto Lead
6. Radiator Bracket
Cable, Wire and Hose Routing
KX250:
1. Clamps
2. Left Radiator
3. Right Radiator
4. To the steering stem hole.
5. Air Vent Hose
6. To the fuel tank cap
7. Band
8. Carburetor Lead Connector
9. Run the radiator overflow tube outside of the engine mount bracket.
10. Carburetor
11. Clamp the air vent hoses with clamps which are installed together with engine sprocket cover and run them along with the engine sprocket cover.
12. Clamps
13. Air Vent Hoses
14. Run the radiator over flow tube between frame and right radiator.
15. Pay attention to inflaction of the radiator overflow tube.
Cable, Wire and Hose Routing
KX125/250-M1 Model
Cable, Wire and Hose Routing
1. Front Brake Reservoir
2. Banjo Bolts
3. Clamp
4. Clamp Brackets
5. Hose Guard
6. Front Brake Disc
7. Front Fork Guard
8. Bleed Valves
9. Front Brake Caliper
10. Rear Brake Caliper
11. Caliper Guard
12. Clamps
13. Rear Brake Reservoir
14. Rear Brake Master Cylinder
15. Bend the cotter pin end by along the joint pin.
16. Rear Brake Disc
17. Disk Guard
Cable, Wire and Hose Routing
KX125/250-M2 Model
∼
Cable, Wire and Hose Routing
1. Front Brake Reservoir
2. Banjo Bolts
3. Clamp
4. Clamp Brackets
5. Front Brake Disc
6. Front Fork Guard
7. Bleed Valves
8. Front Brake Caliper
9. Rear Brake Caliper
10. Caliper Guard
11. Clamps
12. Rear Brake Reservoir
13. Rear Brake Master Cylinder
14. Bend the cotter pin end by along the joint pin.
15. Rear Brake Disc
16. Disk Guard
Year
2003
2003
2004
2004
2005
2006
2007
2008
Model
KX125-M1
KX250-M1
KX125-M2
KX250-M2
KX125-M3
KX125M6F
KX125M7F
KX125M8F
Beginning Frame No.
JKAKXRMC
□
3A000001 or
JKAKX125MMA000001
JKAKXMMC
□
3A000001 or
JKAKX250MMA000001
JKAKXRMC
□
4A010001 or
JKAKX125MMA010001
JKAKXMMC
□
4A010001 or
JKAKX250MMA010001
JKAKXRMC
□
5A016001 or
JKAKX125MMA016001
JKAKXRMC
□
6A021001 or
JKAKX125MMA021001
JKAKXRMC
□
7A025001 or
JKAKX125MMA025001
JKAKXRMC
□
8A 027001 or
JKAKX125MMA027001
□
:This digit in the frame number changes from one machine to another.
Part No.99924-1298-07
Printed in Japan
The public link to your chat has been updated. You may view and manage your chat links after registration here.
Advertisement
125cc two-stroke engine for explosive acceleration and lightning-fast response
Lightweight chassis and nimble handling for easy maneuverability
Advanced suspension system for exceptional stability and control
Powerful brakes for precise stopping power
KX125 is designed specifically for motocross racing, making it the perfect choice for riders who demand the ultimate in performance and handling
With its user-friendly features and exceptional performance, the KX125 is also a great choice for beginner riders who are looking to take their motocross skills to the next level
125cc two-stroke engine
125cc
This information is not available in the provided manual
Why is float height important, and how is it adjusted?
Float height is a critical measurement that affects the fuel level. Adjusting the float height involves bending the tang on the float arm. Increasing the float height lowers the fuel level, and decreasing the float height raises the fuel level.
What should be inspected on the float valve needle during maintenance?
The float valve needle should be inspected for wear on the plastic tip. A worn needle can cause the engine to not idle smoothly. The movement of the rod within the float valve needle should also be checked for smooth operation.
What maintenance is required for the exhaust valve and muffler system?
The exhaust valve should be cleaned and inspected. Check the exhaust system and the muffler body for damage (dents, cracks, rust) and replace the muffler if necessary. If the exhaust noise becomes too loud or engine performance drops, the muffler baffle should be replaced.
Login to continue
