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CLUTCH GAP
Clutch gap is the amount that the clutch shoe moves before it contacts the clutchbell. This affects
the WAY that the clutch engages more than WHEN it engages.
Clutch gap must be adjusted BEFORE clutchbell endplay, and is done with only the outermost
(smaller) ball-bearing and thrustbearing assembly installed; DO NOT install the innermost (larger)
ball-bearing.
EFFECTS OF CLUTCH GAP ADJUSTMENT
Larger gap
• Harder
engagement
• More
sudden
acceleration
• Better on a wider track or high-traction track
• Puts excess stress on the clutch components, especially the thrustbearing
Smaller gap
• Softer
engagement
• Smoother
acceleration
• Better on a tighter track or a track with low traction
• May result in engine bogging and premature clutch shoe wear
ADJUSTING CLUTCH GAP
Clutch Gap – Initial Setting:
0.6–0.7mm
In the images shown here, clutch gap is the difference between values A and B. You adjust
clutch gap by placing shims (medium size) on the thrustbearing collar in front of the
thrustbearing assembly.
1. Install only the clutchbell, outermost ball-bearing (small) and thrustbearing assembly on
the engine crankshaft; DO NOT install the innermost ball-bearing (large).
2. Push the clutchbell onto the clutch shoe, and then measure the distance A as indicated.
3. Pull the clutchbell away from the clutch shoe, and then measure the distance B as
indicated.
4. The clutch shoe clearance is calculated as A–B; the initial clearance value is
0.6–0.7mm
You can easily calculate the thickness of shims required to set the correct clearance value.
Thickness of shims required (in mm) = A – B – 0.7
Example:
For example, using the values A=5.5mm, B=4.5mm
Shim thickness = 5.5-4.5-0.7=0.3mm
5. Place the proper amount of shims directly onto the thrustbearing collar, followed by the
thrustbearing assembly (as shown).
CLUTCHBELL ENDPLAY
Clutchbell endplay is the amount that the clutchbell moves along the crankshaft. Endplay should be adjusted to a minimal amount, and the
clutchbell should rotate freely without binding.
Endplay must be adjusted AFTER clutch shoe clearance, and is done with the clutch fully built (including all bearings, spacers, etc.).
EFFECTS OF EXCESSIVE CLUTCHBELL ENDPLAY
When the clutch is disengaged, the thrustbearing plates are further apart. When the clutch engages, the thrustbearing plates travel further before
they are ‘sandwiched’ together. By traveling further, more force is built up so when the clutch engages, the thrustbearing has more force suddenly
applied to it.
Too much clutchbell endplay will cause premature thrustbearing wear and eventual failure.
XCA CLUTCH
A
Pull
Push
B
CLUTCH GAP SHIMS
Summary of Contents for NT1
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