 More clutch wierdness - help.
Here's the long story:
Did a trackday at Brands on 7th May. Halfway through the afternoon I noticed the clutch lever was a lacking in travel and a bit "floppy".
Inspection revealed the tell-tale signs of hydraulic fluid on the sidestand - "Aha" I thought, "clutch slave cylinder seal is weeping".
Blagged a bit of fluid off a kind chap and finished the day with the clutch still working but not perfect - it wasn't slipping so it was fine.
Couple of days later, invested £2.81 on a new seal and plopped the piston out, cleaned bore, new seal, bled system and felt satisfied that the old girl had done over 130 miles on track for one minor and easily remidied fault.
Couple of days later, went up to Box Hill, after a few miles the clutch was slipping like a *******.
Came home and on inspection noticed that the clutch pressure plate was not sitting tight on the clutch pack - it was like the clutch was partially engaged.
Re-bled the hydraulics and in doing so the pressure plate sat back tight on the clutch pack. I have a bleed nipple at the lever end so I bled it from both ends.
Went out for another ride and again, slipping after a few miles.
This weekend I stripped out all the plates etc and they are showing signs of serious slippage i.e. shiney bronze on the friction plates.
As a bit of a bodge, I swapped some of the knackered friction plates with some not so worn ones from a 748 (yes, I know they are thicker than SPS ones but they were part worn and about 2.5mm thick so should not effect the stack height).
Just been out for a ride - no slipping to report after some very serious "testing" - however, the clutch bite point changed after a few miles so that it would disengage with only a slight lever pull. It made pulling away from junctions a bit of a pain.
Something is expanding in the system so that when it gets hot it's like the clutch pushrod is getting longer and pushing on the pressure plate!
I marked the pressure plate centre bush (the bit that the rod engages in) with a chalk mark and started the engine - the bush does not rotate with the spinning clutch. This means the rod isn't rotating and so all the rod bearings must be OK. This means that the rod isn't heating up the slave cylinder piston and doing wierd stuff to the fluid.
Any thoughts from clever people out there?????
Cheers,
R  | 
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