yamaha yds-3 and ym-1 models
Yamaha YDS-3 and YM-I
MOTORCYCLE
YAMAHA YDS-3 AND YM-1 MODELS
MODEL
Displacement—cc
Bore—MM
Stroke—MM
Number of cylinders
Engine lubrication
Spark plug—
NGK
Electrode gap—MM
Inch
Ignition—
Point gap—MM
Inch
Timing—MM BTDC
Electrical system voltage
Battery terminal grounded
Tire size—Front
Rear
Tire pressure—
Front—kg/cm2
Psi
Rear—kg/cm2
Psi
Rear chain free play—MM
Inch
Rear chain size
Number of speeds
* YDS-3C models use 3.50x18 rear tire.
YDS-3
246
56
50
2
Oil Injection
YM-1
305
60
54
2
Oil Injection
B-8HC
0.6-0.7
0.024-0.028
B-8HC
0.6-0.7
0.024-0.028
0.30-0.35
0,012-0.014
1.8
6
Neg
3.00-18
3.25-18*
0.30-0.35
0.012-0.014
2.0
6
Neg
3.00-18
3.25-18
1.6
22
2.0
28
16-20
%-%
#525
5
1.6
22
2.0
28
16-20
%-%
#525
5
Illustrations courtesy of Yamaha International Corporation
MAINTENANCE
SPARK PLUGS. Recommended
spark plug electrode gap is 0.6-0.7MM
(0.024-0.028 in.). Suggested spark plug
for normal use is NGK type B-8HC.
Champion L-5 or L-81 can be used.
CARBURETORS. Two Mikuni VM
carburetors are used. Idle speed should
be set at approximately 1,200 rpm by
turning adjusters (2—Fig. Y5-1). Make
sure that throttle slides (7) both stop at
exactly the same position and exhaust
pressure is the same for both cylinders.
Idle mixture is changed by turning
needles (11). Initial setting is V^. turns
open. Turning the needle counterclockwise leans the mixture. Carburetors must IBB synchronized to open ex-
actly the same amount by turning
cable guides (1) on top of each carburetor. To synchronize, begin by
turning idle speed adjusters (2) all the
way down, then adjust cable guides (1)
to begin raising throttle slides at the
same time. Throttle cables must have
some slack (free play). After carburetors are correctly synchronized, adjust
idle speed and pump control cable.
Float level (H—Fig. Y5-2) should be
25.5MM (1 in.) and is adjusted by
bending tang (17) on float. Refer to Fig.
Y5-1 and the following standard specifications:
YDS-3 and YDS-3C
MainjetO)
#120orl30
Pilot jet (14)
#20
Needle jet (13)
0-0
Valve needle (6)
4D4
Clip (5) in second groove from top of
needle (6).
YM-1
MainjetO)
#130
Pilot jet (14)
#20
Needle jet (13)
0-0
Valve needle (6)
4D4
Clip (5) in second groove from top of
needle (6).
Flg. YS-1-Bxptoded view of Mikuni VM carburetor. Starting valves for both carburetors are
connected with rod (12).
1.
2.
3.
4.
5.
6.
7.
8.
Throttle cable guide
Idle speed adjuster
Idle speed rod
Retainer
Clip
Valve needle
Throttle slide
Starting valve
328
9.
10.
11.
12.
13.
14.
15.
16.
Main jet
Fuel inlet valve
Idle mixture needle
Link rod
Needle jet
Pilot jet
Starting jet
Float
IGNITION AND ELECTRICAL.
All models are equipped with a battery
ignition system with an individual set
of breaker points, condenser and coil
for each cylinder. The generator is
mounted at the right end of the crankshaft and the breaker points are
mounted on the generator stator.
17 IB
Fig. Y5-2-Float level (H) Is adjusted by bending
tang (17).
Breaker point gap at maximum
opening should be 0.30-0.35MM (0.0120.014 in.). The breaker points should
just open when the piston is 1.8MM
(0.071 in.) BTDC on YDS-3 models and
2.0MM (0.079 in.) BTDC on YM-1
models. Ignition timing must be
checked and adjusted individually for
each cylinder. A static timing light or
meter can be used to indicate point
opening and a dial indicator in the
spark plug hole to position the piston.
Timing is changed by moving the
breaker point assembly in the elongated holes after loosening the two
mounting screws.
LUBRICATION. The engine is lubricated by oil contained in a separate
tank. A pump and metering unit
pumps oil from the tank to each cylinder inlet passage. The oil should
never be allowed to run dry. SAE 30
two-stroke oil should be used. The oil
pump control cable should be accurately adjusted to provide the correct
amount of oil. If the cable adjustment is
incorrect, the engine may be damaged.
Before adjusting the pump control
cable, it is important that the throttle
cable guides (1—Fig. Y5-1) are correctly set. To adjust the throttle cable
guides, turn the idle speed adjusters (2)
all the way down, then synchronize
cable guides (1) so that both throttle
slides (7) begin to move at exactly the
same time when the hand grip is
turned. The throttle cables should have
approximately 1/16-inch free play after
they are synchronized. Adjust the idle
speed to 1,100-1,300 rpm by turning
both idle adjusters (2). Make certain
that both throttle slides stop at exactly
the same time. Turn the throttle hand
grip just enough to take up free play
from the throttle cables (without
changing idle speed) and check the oil
pump setting mark and guide pin as
SERVICE
Yamaha YDS-3 and YM-1
3 5
6
9
Fig. Y5-10-The dutch adjusting screw (S) is io*
cated under the small, round cover on engine
ieft side cover.
10 4 8
Fig. YS-7-Ciearance (A) should be 0.2S-0.35MM
and Is adjusted by varying shims (8).
Fig, YS-S-When carburetor controls are correctly
adjusted and engine is at idle speed, mark (1)
should be aligned with guide pin (2), Cabie adjuster is shown at (3). Clearance (C) at idie
shouid be 0.3S-0.40MM,
shown in Fig. Y5-5. If the "V" mark (1)
is not exactly aligned with guide pin
(2); loosen the lock nut and turn the
pump cable adjuster (3) as required for
alignment.
Check the minimum plunger stroke
by turning starter plate (16—Fig. Y55) until clearance (A—Fig. Y5-7) between pulley and adjusting plate is at
minimum. Clearance (A) should be
0.25-0.35MM (0.0098-0.0138 inch). If
clearance is incorrect, add or deduct
shims (8),
Fig. Y5-9-The clutch hand iever should have 23MMfreepiatat(A).
If oil lines are drained or pump is
removed, it is'important that all lines
be filled before starting engine. Remove bleeder screw (B—Fig. Y5-5) and
pull the control cable up out of cable
guide (3). Turn starter plate (16) until
oil without air bubbles flows from the
bleeder screw hole, then reinstall
bleeder screw (B) and start engine. Run
engine at idle speed until oil delivery
lines (20—Fig. Y5-6) are free of air
bubbles.
Fig. YS-6-Expioded view of the oii injection pump unit. Bieeder screw is shown at (B).
1.
2.
3.
4.
5.
6.
7.
8.
9.
Pump case
Cover
Pulley spring
Adjust pulley
Guide pin
Adjust plate
Snap ring
Shims
Plunger
10. Plunger return
spring
11. Cam guide pin
12. Plunger oil seal
13. Plunger cam oil seal
14. Distributor
15. Oil seal
16. SUrter plate
17.
18.
19.
20.
21.
22.
23.
24.
Drive pin
Check balls
Springs
Delivery^ipes
Bai\io bolts
Iryectorbolt
Worm wheel
Worm wheel pin
25.
26.
27.
28.
29.
30.
31.
32.
33.
Spring
Worm shaft
Bushing
Oil seal
Spring seat
Drive gear
Worm wheel plate
Wave washer
Plate
The gear box contains 1.7 quarts of
SAE 30 or lOW/30 motor oil and should
be drained and refilled every 2000
miles.
CLUTCH CONTROLS. The clutch
hand lever should have l/16-y8 inch
free play at (A—Fig. Y5-9). To adjust,
remove the cover from left side of engine and loosen lock nut. Turn the adjusting screw (S—Fig. Y5-10) in until
slight resistance is felt, then back
screw out V4 turn and tighten lock nut.
Turn the cable guide at ends of cable
until the hand lever free play (A—Fig,
Y5-9) is correct.
SUSPENSION. Each front suspension unit contains 200cc of oil. The oil
used should be a mixture of 80%SAE
30 motor oil and 20% SAE 60 spindle
oil. Oil should be renewed every 4,000
miles.
Fig. YS-12-€xpioded view of the front suspension
system.
1.
2.
3.
4.
5.
6.
7.
8.
Filler screw
Seal
Cover
Guide
Washer
Cover
Spring seat
Spring
9.
10.
11.
12.
13.
14.
15.
16.
Spring seat
Washer
Oil seal
Inner tube
Tube nut
"O"ring
Bushing
Lower tube
329
MOTORCYCLE
Yamaha YDS-3 and YM-1
8E
21
Fig, YS-i4-Exploded view of the crankshaft assembly. Parts (8E & T4£) should be discarded if
later type seat (13 & 14) is installed.
I. Oil seal
2. Bearing cover
3. Main hearings
4. Shims
5. Crankshaft right
cylinder half
6. Shims
7. Center main bearings
8. Snap ring
8E. Snap ring (early
motfelst
9. Gasket
10. Pin
11. Filler piece
12. Center housing
13. "0" ring (late type)
14. Center seal (late
type)
14E. Center seal (early lip
K'pe)
15. Crankpin
16. Crankpin washers
17. Crankpin bearing
18. Connecting rod
19. Piston pin bearing
20. Shim
21. Snap ring
22. Oil seal
23. Collar
REPAIRS
PISTONS, RINGS AND CYLINDERS. Each piston can be removed
after removing exhaust pipe, carburetor, cylinder head and cylinder. Refer
to the following specifications:
Ring end gap—
Top ring
0.15-0,30MM
(0.006-0.012 in.)
Second ring
0.1-0.2MM
(0.004-0.008 in.)
Standard cylinder bore diameter
YDS-3
56MM
(2.20 inch)
YM-1
60MM
(2.36 inch)
Maximum cylinder bore taper
or out of round
0.05MM
(0.002 in.)
Fig. Y5-1B-Exptoded view of
the clutch assembly. Parts
(1, Z & 3) are located In the
left cover.
1. At^usting screw
2. Return spring
3. Release fever and screw
4. Push crown
5. Release bearing
6. Nut
7. Lock plate
8. Clutch drum
9. Spring cup
10. Spring
11. Drive plate
12. Friction discs (5 used)
13. Clutch plate (4 used)
14. Clutch plate (thick)
15. Snap ring
16. Thrust washers
17. Inner thrust washer
18. Primary drive gear hearing
19. Clutch nuh anti primary drive
gear
20. Thrust washer (larger I.D.)
21. Thrust washer (small I.D.)
21 20 19
Fig. Y5-19-Bxploded view of
2 4
transmission. Refer also to
Fig. Y5'20.
1. Snap rings
2. Ballbearings
3. Needle bearing
4. Spacer
5. Washer
6. Shim
7. Thrust washer
8. Kick starter pinion
9. Spacer
10. Washers
11. Washers
12. Setting plate
13. Shim
14. Oil seal
15. Collar
17. Input shaft
18. Setting plate
25. Third gear
19. Second gear
20. Third &fifthgear 26. Fifth gear
27. Fourth gear
21. Fourth gear
28. Output shaft
22. Oil catcher
29. Spacer
23. First gear
30. Output sprocket
24. Second gear
10
1 2
Piston skirt to cylinder clearance—
YDS-3
0.050-0.055MM
(0.0020-0.0022 in.)
YM-1
0.054-0.058MM
(0.0021-0.0023 in.)
Piston skirt clearance in cylinder
bore should be measured by first measuring piston diameter at right angles
to piston pin and cylinder bore diameter, then subtracting. The piston
should be measured lOMM (0.4 inch)
above bottom edge of skirt. The dark
piston ring should be installed in lower
groove and chrome plated ring should
9
1
18 19
20
21
S 1 3 !
be in top groove. Make sure that rings
correctly engage pins in the ring
grooves. Pistons should be installed on
connecting rods with arrow pointing
toward front. Cylinder head stud nuts
should be torqued to 180 inch-pounds.
CONNECTING RODS AND
CRANKSHAFT. The c r a n k c a s e
halves must be separated to remove the
crankshaft. Connecting rods, crankpins, rod bearings and the center main
bearings are removed by pressing the
crankshaft apart. The crankshaft
Fig. Y5-20-Cross sectional
view of the transmission
assembly showing location
of spacers and washers.
rT
B C
r
Fig. Y5-1S-Refer to text to check crankshaft for
correct assembly or wear.
330
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
U.
12.
13.
14.
15.
Snap rings
Ballheai-ings
Needle bearing
Spacer 11.8MM)
Washer (l.OMM)
Shim
Thrust washer O.D. 26MM
(l.OMM thick)
Kickstarter pinion
Spacer O.D. 28MM (l.OMM
thick)
Washer8O.D.32MM(1.0MM
thick)
Washer O.D 26MM (l.OMM
thick)
Setti. late
ShimO ».34MM(1.2MM
thick)
OiUeal
Collar
15
SERVICE
Yamaha YDS-3 and YM-1
should be disassemhled ONLY if required tools are available to correctly
check and align the reassembled
crankshaft. If side shake (G-~Fig. Y515) at piston pin end of connecting rod
exceeds 2MM (0.08 in.), the connecting
rod, crankpin and lower bearing should
be renewed. Shake (G) should be 0.8l.OMM (0.032-0.039 in.). Side clearance of connecting rod between the
crankshaft counter weights can be
measured with a feeler gage. Side
c l e a r a n c e should be 0.1-0.3MM
Set mark
Spring hooking hole
Fig. Y5-2t-Mark on klckstarter gear should be
aligned with spring hooking hole as shown.
(0.0039-0.012 in.). With crankshaft
supported between lathe centers (S—
Fig. Y5-15), maximum eccentricity
when measured with dial indicator at
points (A & F) should not exceed
0.03MM (0.0012 in.) and should not
exceed 0.06MM (0.0024 in.) at points
(B,C,D&E).
14 13
10 12
2120
8
Fig. Y5-24-Cross sectionai view of the shift assembly. Refer to Fig. Y5-25 for iegend.
CLUTCH. The multiple disc wet
type clutch is located on the left end of
the crankshaft. The clutch can be removed after removing the engine left
side cover and the clutch retaining nut
(6—Fig. Y5-16).
Clutch friction discs (12) should be
renewed if less than 4MM (0.158 in.)
thick. Thickness when new is 4.3MM
(0.169 in.). Free length of clutch
springs (10) should be 25.4MM (1 in.).
Springs should be renewed if less than
23.5MM (0.925 in.). Inspect all parts
for wear, warpage or evidence of overheating.
CRANKCASE AND GEAR BOX.
The 5 speed transmission is shown in
Figs. Y5-19 and Y5-20. The kickstarter
gear should be installed on shaft with
mark on gear aligned with spring
hooking hole as shown in Fig. Y5-21.
Shifter stop bolts (S—Fig. Y5-22)
should have approximately lMM (0.04
in.) clearance as the stop ball falls into
detent in the cam.
Fig. Y5-25-Exptoded view of
shift assembly. Shift fork (1)
moves gear (2G-Flg. Y5-19),
fork (2) moves gear (20-Flg.
Y5-19) and fork (3) moves
gear(24-Fig.Y5-19).
Fig. Y5-22~Gear change stop bolts (S) should
have approximately 1MM clearance when stop
bail engages detent in shifter cam.
Ohaf^e ring
Fig. Y5-23-View of shift change ring Installation.
1. Shia fork (5th)
2. Shift fork (2nd & 4th)
3. Shift fork (1st & 3rd)
4. Shift rotor (3 used)
5. Stop pin (3 used)
6. Shift rails
7. Shift cam
8. Shifter pawls
9. Pawl holder
10. Working plate
11. Mounting plate
12. Change link
13. Cam detent ball
14. Detent spring
15. Change lever
16. Return spring
17. Eccentric screw
18. Shift pedal shaft
19. Washer
20. Shims
21. Snap ring
22. WasTier
23. Snap ring
24. Oil seal
25. Seal
26. Pawl plate
27. Shift pedal
28. Shift pawl spring
I
331
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement