Installation Guide

The Rekluse z-Start Pro Auto-Clutch Kit
Doc ID: 191-277
Doc Rev: 121412
2000+ Yamaha TT-R 125
Watch the complete installation video on our website at
Be sure to use proper eye protection
Laying the bike on its left side allows for easy clutch access and eliminates the need to drain oil
An air or electric impact wrench works well to remove the center clutch nut, or you can place the
bike in top gear and hold the rear brake while loosening the center clutch nut with a socket
Channel-lock style pliers work best to bend the tabs of the washer up over the center clutch nut
8mm & 19mm sockets
10mm end wrench
3mm & 6mm Allen key
¼” Driver for included T10 Torx bit
2 sets of feeler gages
Fine-Tooth Metal File
Torque wrench (in-lb or N-m)
©2012 Rekluse Motor Sports
Rekluse Motor Sports, Inc.
12000 W Franklin Rd
Boise, Idaho 83709
Note: The Lower Assembly is packaged underneath the Pressure Plate and held in place with two
screws through the Top Plate.
Note: The ½” Throw-out Washer and Throw-out Spacer pictured above are not needed for this model.
©2012 Rekluse Motor Sports
Rekluse Motor Sports, Inc.
12000 W Franklin Rd
Boise, Idaho 83709
Note: spare screws, balls and shims may be included with your clutch
 Top Plate
 12x M3 T-10 Torx Screws
 Lower Assembly
 15x 3/8” (9.53mm) Tungsten Carbide
 4x .055” (1.4mm) Drive Plates
 30x 3/8” (9.53mm) Steel Balls
 4x M5 Head Screws
 .045” (1.14mm) Center Clutch Guide
 ½” (12.7m) Throwout Needle Thrust
 20x M5x1.0mm washers (to go back to
 1.5” (38mm) Wave Spring (CL150L1)
 1.5” (38mm) Wave Spring (CL150L2)
The z-Start Auto Clutch functions through centrifugal force. As engine RPM increases, the balls
contained in the z-Start Pressure Plate travel up the ball ramps and push against the Top Plate. This
action forces the Pressure Plate to engage the clutch pack.
In order for the z-Start Clutch to perform properly, it must be mounted properly.
 Measuring and maintaining the Installed Gap is critical. If the Installed Gap is too big the clutch will
slip excessively and cause rapid clutch wear. If the Installed Gap is too small, the clutch will drag
and cause engine stall.
Recognize that the Pressure Plate travels along the tabs of the Lower Assembly as it engages and
disengages. Anything preventing this travel will prevent full engagement and cause the clutch to
slip excessively.
Be very careful not to drop any screws, washers or springs into the crankcase opening! It is
surprisingly easy to drop a little screw or washer down into your crankcase. It is not always so easy to
get it out. Make sure all parts going in and coming out are accounted for before you finish the
installation. A strong magnetic probe can often be used to retrieve little parts if you happen to drop
something in
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Attention TTR 125 Customers: The following outlines Clutch Basket Dampener Failure. Some Clutch
baskets will last a season, and some last only hours. If the dampeners go unchecked clutch damage
will result. After reading through the following continue on with the z-Start installation and inspect
Background for Clutch Basket Dampener Failure:
The OEM Clutch Baskets for the TTR 125 use elastometer dampeners to protect the clutch from shock
loading applied to the basket by the drive train and/or engine during normal operating conditions. The
dampeners are located inside the clutch basket behind the ring gear. The dampeners take up the slack
between the ring gear and clutch basket so that under normal loading they rotate as one. Under
extreme loading the dampeners provide a cushion so the ring gear and basket can float independently
and keep shock loads from being transferred to the clutch.
As the dampeners wear and shrink the system gains slack and shock loads start getting transferred to
the clutch. This creates hammering between the clutch basket and ring gear. The hammering transfers
to the clutch plates and causes the plates to wear away at the clutch basket and center clutch hub. The
aluminum core portion of the TTR basket can have casting flaws at the base of each tang (see
following picture) and with loose dampeners the hammering can case the tangs to fracture and break
away from the basket causing severe engine damage.
Checking Your Clutch Basket for Dampener failure:
Prior to installing the z-Start, it is recommended that you check the radial fit between the ring gear and
basket core. To do this, remove the basket (when you remove the center clutch for standoff
modification) and hold the ring gear in one hand and the basket core in the other and try to rotate the
two parts independent of each other. Ideally you should feel little to no give between the two parts. If
you are able to rotate the two parts easily and the fit feels loose then the basket needs to be replaced.
See the following picture.
Casting void which allows
cracks to propagate
leading to tang fracture
Twisting the aluminum basket body
and ring gear in opposite directions
to check for loose dampeners.
Maintaining Clutch Basket Dampeners:
Unfortunately the OEM clutch basket does not provide a means to maintain the dampeners. After the
dampeners wear out, the clutch basket must be replaced. The choice is either an OEM clutch basket,
or an after market basket. The advantage of an after market basket is that the basket core is usually
billet aluminum which is much less likely to fracture even with loose dampeners.
Warning: Installing the z-Start into a worn out clutch basket can greatly reduce clutch
performance, and damage the z-Start Pressure Plate.
1. Turn the gas petcock to the off position and route the gas cap vent tube into the air. When you
lay the bike over on its side, the gas in the bowl will drain out of the overflow tube. Be prepared
to catch the gas in a suitable container to prevent a fire hazard.
2. Disconnect the clutch cable from the clutch lever. Carefully lay the bike on its left side so the
clutch-cover faces up.
3. Remove the kickstart and rear brake pedal. Remove the right side case cover bolts with an
8mm socket and carefully remove the clutch cover.
Note: On electric start equipped models you will need to remove the two 8-mm bolts holding it
to the case cover. Simply pull it out and rotate it out of the way of the cover.
4. Using an 8mm socket, remove the 4 bolts and springs holding the stock pressure plate to the
inner clutch hub.
5. Using a 10mm wrench, remove the nut that is securing the Throw-out to the Pressure Plate.
Next, remove the stock Pressure Plate. See following picture.
The Pressure plate, 4 bolts, and springs are not reinstalled.
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6. Thread the nut that was previously removed from the top of the Throw-out up the backside of
the Throw-out. Adjust the position of the Throw-out Thrust Washer by threading the top nut
down so there are 4-5 threads showing past the top nut. See following pictures.
Top Nut and Washer
moved to backside of
the Thrust Washer
Throw-out Thrust Washer
adjusted so 4-5 threads are
visible above Top Nut.
Remove your clutch pack and set it aside. Keep it in order because it will be re-installed.
8. Remove the center clutch by folding back the Tab Lock Washer and using a 19mm socket. Take
the center clutch to a place where no filings can be dropped into the engine case opening.
Ensure the Thrust Washer behind the center clutch remains on top of the clutch basket. See
following picture.
Thrust Washer sitting on
top of clutch basket.
Note: 20 x M5 x 1.0-mm washers are provided so the clutch can be re-assembled to the stock
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9. Place the included 0.045” Center Clutch Guide over the studs on the center clutch and use a
fine tooth file to file the studs down smooth with the Center Clutch Guide. Remove the guide
and use some emery cloth to smooth the studs’ edges. See following pictures.
File studs down so they are flush with the included Center clutch guide.
Note: Per the Basket notice on page 4, check the basket for excessive basket dampener play.
10. Clean the Center Clutch of filings and reinstall the Center Clutch. Make use of the stock Tab
Lock Washer and use a 19mm socket to torque the nut 50 foot pounds. Ensure that the thrust
washer is in place between the clutch basket and center clutch.
Note: 20 5-mm x 1-mm thick washers are included to return the 4 stand-offs to stock height. If
returning the clutch to stock, place 5 washers on top of each standoff.
11. Re–install the clutch pack, but exchange one stock .047” drive plates with a Rekluse .055” drive
plate. The additional Rekluse .055” drive plates are used to compensate for clutch pack wear.
Note: At this point you will have 1 stock drive plate removed from you clutch pack.
12. Place the z-Start Lower Assembly over the 4 center clutch stand-offs. Line up the countersunk
holes of the Lower Assembly with the holes in the center clutch standoffs. Only 2 countersunk
holes are visible at one time—you will have install 2 M5 flat head screws then rotate the
Rotating Hub to install the remaining 2 screws. Apply blue Loctite 243 to all 4 screws and torque
the M5 screws to 96 inch pounds. After the 4 screws are torqued-down, the Rotating Hub
should spin freely. See following pictures.
Installing First 2
M5 screws.
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Rotate Rotating Hub and
install remaining 2 - M5
13. Guide the reconfigured stock Throw-out into the hole in the transmission input shaft.
Place the ½” Needle Thrust Bearing on top of the Stock Throw-out.
Place the 1.5” C150L2 Wave Spring on top of the Lower Assembly. The C150L2 Wave Spring is
the taller of the two wave springs provided with the kit. This is our recommended setting for
engagement RPM—refer to the chart on the last page of these instructions for other adjustment
Needle Thrust
Warning: Perform the next step away from the bike to keep the balls from falling into the
14. Place a small amount of oil in each of the Pressure Plates ball grooves. You will use the 15
Tungsten Carbide balls and 15 of the steel balls. Install 1 Tungsten Carbide ball followed by 1
steel ball into the ball grooves. Work your way around the pressure plate in this alternating
pattern so that the clutch will be balanced. The tungsten balls are heavier so if you get them
mixed up you can tell them apart.
Note: You will have 15 steel balls left over.
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15. Place the z-Start Pressure Plate over the z-Start Lower Assembly. Index the outer tabs of the
Pressure Plate into the “half-moon windows” of the clutch basket. The outer tabs of the
Pressure Plate index into the same clutch basket windows the outer tabs of the friction
disks do.
Also ensure that the tabs of the Lower Assembly pass through the associated cut-outs in the
Pressure Plate. Make sure the top of the Rekluse Throw-out assembly passes through the hole
in the center of the z-Start Pressure Plate. See following picture.
Tabs Passing
through Pressure
passing through
center of
Pressure Plate.
Outer Tabs
Indexed into
Basket Slots.
16. While holding the Pressure Plate down place the Top Plate over the Pressure Plate and fasten
it to the tabs of the Lower Assembly with three of the M3 screws in a triangular pattern. Lightly
tighten each screw using a ¼” driver and the included Torx T10 driver tip. See following
Holding down Pressure
Plate until Top Plate is
securely fastened.
Note: You will have to overcome the z-Start Wave Spring and hold the Pressure Plate down until the
3 screws are securely fastened in order to tighten the Top Plate down properly.
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17. Measure the installed gap of the z-Start. Two sets of feeler gauges are required to measure the
Installed Gap. The feeler gauges must be placed between the top most friction disk and the
top-most steel drive plate in the clutch pack 180° apart. See following pictures.
Note: Insert the 2 sets of feeler gauges directly across from one another (180° apart) to avoid
the clutch pack from rocking resulting in an inaccurate measurement. Find the thickest feeler
gauge that still slides back and forth with slight resistance.
Your installed gap measurement above needs to be between .040” (1mm) to .050” (1.15mm).
.045” is ideal.
If the gap is greater than .045”, you need to exchange out one stock .047” (1.2mm) steel drive
plate in the clutch stack and replace it with a Rekluse .055” (1.4mm) steel drive plate. Exchange
stock .047” (1.2mm) drive plates with Rekluse .055” (1.4mm) drive plates or vice versa as
needed to get the correct measurement. Repeat steps 16 and 17 until measurement is within
18. Using a small amount of Blue Loctite 243, install the rest of the M3 torx head screws and torque to
10 inch/pounds. 10 inch-pounds requires a good crank with the included Torx T10 driver tip, but be
careful not to bend the head of the T10 driver tip. Remove the three marked M3 screws, add
Loctite, and tighten. Note: Use Loctite 243 (Blue, oil resistant) to secure all M3 Torx screws
19. ‘00-‘03 Models Only: Go to step 21.
‘04+ Models Only: To eliminate interference with the z-Start Auto Clutch in ‘04-‘08 TTR models,
you must grind off one of the ribs located on the inside of the clutch cover. You must grind it off
almost flush with the inner side of the cover to prevent interference. A Dremel tool works well for
this. See following pictures.
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Rib that is
Kick Start Shaft
Rib after it is ground
20. The above pictures show the rib that needs to be removed and how far it needs to be ground
down. When grinding down the rib, be careful to keep aluminum shavings out of the various oil
passages inside the cover—rags and tape work well. When done be sure to clean shavings out
of the cover to keep them out of the motor.
21. Re-install your clutch cover and torque the clutch cover bolts to 6 to 8 foot/pounds. Re-install the
kick-start and brake pedal. Re-install starter if applicable.
22. Re-attach the clutch cable to the clutch lever. It is necessary to adjust the slack in the clutch
cable so that there is 5-10 mm of play at the end of the clutch lever when the engine is revved to
at least 4500 RPM. Start the engine and ensure the transmission is in neutral, rev the
engine to 4500 RPM’s, and adjust the clutch cable so that when the engine is revved
there is 5-10 mm of play at the end of the clutch lever.
Warning: The z-Start allows the bike to idle in gear just like if it were in neutral. Quickly revving the
engine with the transmission in gear will cause the bike to lunge forward unexpectedly—always
ensure the transmission is in neutral before adjusting the clutch cable slack.
Warning: Improper clutch-cable slack adjustment can cause excessive clutch slip and ultimately
clutch failure.
WARNING: After a 20 minute break-in period, the clutch plates will seat in and you must re-measure
the Installed Gap to guarantee the Installed Gap is within the prescribed range—make drive plate
adjustments if necessary. See step 17.
Clutch break-in re-measurement of the Installed Gap is necessary whenever new clutch plates are
WARNING: Refer to the “Safety Warnings” and “Break-in Tuning and Maintenance Guide”
before operating the z-Start clutch.
See next page for adjustment options.
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The engine speed at which the z-Start begins to engage the clutch, also called the stall speed, can be
adjusted. Included with the z-Start are two 1.5” Wave Springs. The Wave Springs are located inside
the z-Start between the Pressure Plate and Lower Assembly. To adjust the stall speed, it is necessary
to remove the engine side cover and the M3 screws holding the z-Start Top Plate to access the Wave
Spring. Refer to the z-Start Parts View and the installation instructions for detailed information on how
to change the Wave Spring configuration.
Use the following as a guideline for setting the stall speed. Remember many factors can affect the
stall speed from bike to bike so the following chart is only a guideline. You can also make fine tuning
adjustments by adjusting your idle speed.
CS150L1 Wave Spring
C150L2 Wave Spring
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Low Stall Speed (typically just above idle)
Medium Stall Speed – Recommended setting