Dear Bill,
That is interesting as I had a multi plate clutch on my Rapide. (It wasn't a Japanese one but a C1/V type.) The clutch was new and came with the rest of the bits of bike in the basket case purchase. I read about various ideas of drilling holes in the case to allow a small amount of oil into the clutch compartment. I never tried this as I found that when the clutch was clean and dry it performed very nicely but as soon as it got a very small amount of oil on one of the plates it would have a very erratic and abrupt take up. (Never figured that one out, you would think a bit of oil would promote some slip for a more gentle take up.
) Perhaps I should have persevered and tried running it fully wet.I eventually gave up and sorted through the bits and found that I had almost a complete Vincent twin clutch. I had a few problems with primary case oil getting past the seals which I tracked down to a slightly undersize diameter on the C3 clutch shoe carrier. Once I managed to keep the oil out I spent quite a bit of time experimenting with the adjustment of the pressure on the OP11 & PD27 springs in the clutch shoes. With these set correctly the clutch is a delight to use, very light at the control lever and progressive.
I also have a Ducati twin and that uses a dry clutch. That gets grabby when the dust builds up on the plates.
I know that fitting a Japanese clutch is said to be a good mod and as far as I know all the big Japanese bikes run their clutches in oil and they seem to be bullet proof and able to transmit lots of power. I guess the road to success is to get the right friction material for the application whether wet or dry.
