Aprilia clutch slip

[davidwheeler]

NS 1692 has a second series clutch to go with her enlarged engine.  At first all was well but recently it has started to slip.  When I had the gearbox out to correct second gear (it only fits on the shaft one way otherwise the detent pin is blocked) I checked it out and there was no obvious problem, ie good plate flat surfaces and no sticking and nothing blocking the return of the withdrawal race.  I guess weak spring?  Before I drag it out again, has anybody any advice or a supply of stronger springs?  It would probably be easier with the first series clutch with its external coil springs but the plate is much smaller and would not transmit the power I think and in any case would upset my beautiful Vibration Free balance.

[ben]

I went to Turin in '81 in my Citroen DS23 Safari because of chronic clutch slip in my S1 Aprilia (en-route to the ferry!).I eventually cured it by changing the gear-box although I never put my finger on exactly why that particular box allowed its oil to get onto the clutch.Many years later I up-rated to a S2 engine but have always retained the S1 clutch (with its hair-pin springs around the rim) and have had no problems despite the big increase in torque.
In the dim and distant past the cure(??) for slip due to oil contamination was to introduce Fullers Earth.If you were able to do this(access might be difficult on the Aprilia) it might show if oil on the plate is the problem.
All the best
                 Ben

 

[JohnMillham]

Another way is to squirt the contents of a carbon tetrachloride fire extinguisher on the clutch, but do it in the open and don't sniff it!
 Regards, John

[davidwheeler]

Trouble is, there was not any oil on the plate when I took it apart and gave it a clean anyway - to no avail.

[davidwheeler]

Curiously, after I had rebuilt the front axle and took her out for a test drive the clutch forgot to slip.  It still has not remembered so I wonder if splines were stiff or something...