went for a run friday after getting the carbs about right on an 81 gsx1100 and the plates are holding the power beautifully. towards the end of my run (was to have been the middle) a pull on the lever resulted in more than normal travel and each subsequent pull got longer till fully in wasn't disengaging it at all. while slowing down to around idle in third the oil light and all systems monitor bulbs illuminated. a quick blip of the throttle to change into second and the lights went back out and didn't bother me again. i moped her home and luckily caught only green lights and clear intersections on the way. wondered if the clutch cable had given up the ghost but each draw on it moved the clutch release lever smoothly forward and back.
at home i popped the oil filler cap and could see the pressure plate was indeed moving when the release lever was pushed but the springs weren't being compressed. and the friction plates were moving back and forth with it. brain said that the inner clutch basket must be floating free on its splining and therefore something inside bordering on expensive had occurred. horrible images of shattered alloy, snapped shafts, mangled threads and circlips and other maladies began to flash before my bank statement.
release lever off, brake pedal off, footrest off, sidestand down and off the centrestand then clutch cover off. both the inner and outer baskets could be moved in and out so i plucked the six screws and springs and removed the pressure plate and there she was. the old free floating nut that ain't holding down a bloody thing trick batman! the thread on the spline seems ok but the nut has torn six strips of thread clean out of its centre making a very pretty pattern:
theres a line on the lock washer where it's been used once, flattened out, flipped over and reused and feasibly the nuts been reused and either weakened or overtightened. either way this is the first time i can recall seeing a thread cut through a spline on any axial load bearing application rather than a full thread cut at a smaller diameter and a large washer. i realize it works on who knows how many bikes worldwide but it still seems dodgy.
the oil light i believe came on from the angle cut on the primary drive gears walking the outer basket towards the clutch cover and the four nibs that the pump gear takes its drive from having their driving slots lifted away. a quick look at the manual shows the oil switch hooked up to the systems monitor so thats explained too. that the light went back out gives me the impression that the pump drive relocated itself and hasn't suffered. a new nut and lockwasher will be here wednesday ($10.25. a good deal cheaper than i'd been thinking she'd cost to fix at the beginning)and i might look into the hardened APE nut as time goes on. as a bonus all the plates look ok and the inner and outer plate slots in the baskets are pretty well perfect.
has anyone else experienced the threads tearing out complete rather than a nut simply loosening and causing a rattle? there was no indication of a problem till the whole lot went south and i lost the clutch, and the nut doesn't look like it's rotated or been fretting.
thanks for your time, glen.
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