Cas I think it was Henk who also supplied your piston as it was me who paid for it in exchange for your B33 piston
I think you'd do better to strip your clutch first to see what is needed. It might just be oil on the plates, especially if it's been wet sumping badly. Did you take the level plug out?
The spring free length should be 2 3/8" and replaced at 2 1/8"
there are 8 ferodo discs as standard and are 3/32" thick when new. But after market discs are often thicker which can overcrowd the basket. Even so I always leave one ferodo and one steel plate out as it give a much lighter clutch and more room for separation in the basket. Never slips and both my bikes have bigger than standard engines.
The 1/4"X 1/4" clutch rollers are worth replacing with good quality rollers or at least mike your old ones up. Ron
email (option): ronpier@talk21.com
There's a lengthy article on clutch slip, drag and maintenance in the 'Technical Section' of the website...
You'll need a couple of special tools to do the job, most importantly a compressor for the main clutch spring...
If you need to remove the sleeve that the clutch rollers run on there is an extractor for that as well...I'd read that article before starting, to get an idea of what's going on in there..Ian
email (option): ian@wright52.plus.com