Just to make sure i get this right, this o-ring slides over the right side crankshaft with the connected tab in the keyway and slid all the way on until it contacts the bearing? The tab does not seem to fit into the keyway very elegantly (Vito's 350 crank) so I'm not sure.
Just put a bit of yamabond or whatever case sealer you use on the keyway to seal it and leave the oring out. It only fits some older model 350's that have a machined groove for it
i didnt use one of those seals on my vitos crank. actually, not all years actually use them.
yeah, it's interesting, the 250 crank did not have one when I split the cases but I was told to get the seal by one of the RD shops that are frequently referenced here. But it sounds like I don't really need it based on people's comments.
you don't. if you're worried about incursion, a light smear of rtv the bearing side face of the primary gear will do it. but, ive never ever found it necessary
The O-ring 360-11526-00-00 and matching primary gear were updated in the '74 model year.
Starting with RD250A 352-207570 and RD350A 351-218268. Refer to Tech Bulletin M4-038. Prior to that, no O-ring was installed.
Quote from: SoCal250 on April 13, 2026, 12:10:07 PMThe O-ring 360-11526-00-00 and matching primary gear were updated in the '74 model year.
Starting with RD250A 352-207570 and RD350A 351-218268. Refer to Tech Bulletin M4-038. Prior to that, no O-ring was installed.
That explains that then. This bike is before that update. Thank you!
Old and new
the key is shorter on the o-ring models as well I think
Quote from: 1976RD400C on April 14, 2026, 09:29:12 AMOld and new
yup, mine is pre-seal confirmed by those pics, thanks! if anybody needs that seal, let me know and i'll just throw it in an envelope with a stamp, save somebody a few bucks.