SERVICING THE CLUTCH - SPRITE/NIMBUS MODELS
DISMANTLING:
1. Remove the floorboard.
2. Disconnect the clutch operating arm, unbolt and remove the chainguard (item 32).
3. Remove the locking wire from the conical nut (item 18), compress the clutch slide
(item 29) and unscrew the conical nut (item 18), care should be taken when
releasing the clutch slide as spring tension is considerable.
4. DO NOT touch the 4 clutch mounting bolts (items 22 & 23) on the clutch centre
(item 21). It will be noted that 2 of the bolts are longer, these are for the attachment
of the clutch extractor.
5. Using the extractor withdraw the clutch off the shaft, after the first 2 inches the
centre will pull off freely. Look out for the key (item 27) as it can quite easily fall out
and get lost.
6. Take notice of the position of the clutch shoes (item 11). If refitted incorrectly, clutch
slip will take place, and shoes will wear quickly. Clean the backplate down, grease
the adjuster (item 13) and expander unit (item 12), very lightly remove any excess
grease, make sure that expander is free to move on backplate.
7. Refit clutch shoes and spring. Check the four mounting bolts for tightness.
ASSEMBLING:
1. Locate the key in the keyway (item 27) of the shaft, lightly grease the shaft. Put the
clutch on the shaft, line up the key and keyway and press clutch on until solid.
2. Grease the clutch slide (item 29) and guide rod (item 26), now fit the clutch spring
(item 28) and slide (an easy way of fitting the clutch spring is to compress the clutch
spring in a vice and wire it up. The wire must be cut and removed after the conical
nut has been screwed up, but before final adjustments are made).
3. Compress the clutch slide until the clutch spring is solid, and screw up the conical
nut until coned seat is 1/64" clear of hole.
4. Operate the clutch 2 or 3 times to centralise the shoes then hold the slide in the fully
compressed position and adjust the clutch i.e. Turn the square adjuster screw in a
clockwise direction until tight then slacken off until clutch revolves freely.
IMPORTANT: Wire the conical nut to the clutch slide, refit the chain guard and
clutch operating arm. The gap between the clutch operating arm and the clutch
thrust bearing (item 31) should be 5/16" when the clutch is fully adjusted. When
clutch has been relined it is advisable to re-adjust after 2 or 3 days work.
DO NOT allow the gap between the clutch operating arm and the clutch thrust
bearing to close, this will cause clutch slip. It is advisable to adjust clutch when the
gap closes to 1/8".
To adjust the clutch on site, a special clutch adjusting spanner is provided with each
machine. Two people are required, one to sit on the machine and depress the clutch
pedal, the other to adjust the clutch.
Engage starting handle in starting dog, turn handle until the square headed
adjusting screw is in line with the cut out on the face of the chain guard, insert
special spanner and adjust as described in previous paragraph.
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