I'm getting a bit of clutch slip on my 98 R1 engine. I checked the plates yesterday and they're fine. 0.5mm of wear from nominal across the whole stack of friction plates, the limit is 2mm. The clutch basket nut was a bit loose, leading to some play so I tightened the nut and this time bent over the lock washer The clutch slip is now more pronounced but more limited, strangely. At 8000 RPM at full throttle, it will jump to 8800 until the wheels catch up. Gear changes are a bit more precise now, which is good.

I have a barnett clutch conversion and had to put 2mm thick M12 washers between the top hats and the springs to stop clutch slip when new. Perhaps there's not quite enough clamping force now? Do Barnett do even stiffer springs, or perhaps longer ones?

The plates look in good condition. What could the cause of the slip be?

have you changed from sythetic to semi synth oil? or any other changes in oil type?

were the plates in when you fitted the springs or were they new friction and steels?

Same oil as I've been using for 3 years now, same clutch plates and same Barnett conversion. I'm even using the same gasket as the original stuck to the cover and not to the engine. (copper grease on the new gasket did this

The one I got from Fluke only had one set of springs. Perhaps I could do with the stronger set.