OK, just walked in from playing with the 750. Got the felt from McMaster on Friday, dang those guys are quick to ship. I got a sheet of 1/8 and 1/16 and set about making some new seals.
I measured the OD to be 9/16 and my largest punch is 1/2
so I cut and sharpend a piece of pipe with a 9/16 ID. Stamped out a ring of 1/8 and 1/16 to test the fit. I pulled out the retaining ring and droped in the thicker felt but didn't like it. The 1/8 looks ok.
I had used O-rings on two holes that had nothing in them. The PO had taken this bike apart to "restore it" and never re-assembled. Why two of these rings only? Who the F@#$ knows? When I pulled the others out they had tiny seals, similar to a fork or tachometer seal. My 350 Four had felts, so silly me, I assumed and here I am. It didn't look like the o-rings were wearing or having issue, so I put o-rings throughout.
Wannabe - if you still want a set of these I stamped out a set of 6 that are about 9/16 OD and 7/16 ID PM me.
If anyone wants a piece of felt I have some of that as well. However I'm out of the o-ring stamping biz due to lethargy, riding season, VW tuning, bathroom remodel and so on. The cost of a few postage stamps and envelope won't break me, just let me know which thickness you want.