I have three differant O Ring primary gaskets, Two that are new from Old Britts & one that was in this 850 when I bought it. That one is ever so slightly larger in thickness and much softer then the two new ones that are just a tad thinner but way harder. Since it didn't leak I'm inclined to reuse the old one which is something I would never do other any other circomstances but it seems like I would be foolish to mess with something that works. Have you guys noticed that the soft ones seal better or has anyone else even noticed any differance in them at all ? By the way there was just a hint of some gasket sealer on the face of the cover flat that touches the O Ring, none in the groove. It was so slight I didn't think there was any at first but saw just a light film when I cleaned the cover. What's the best, Soft & slightly thicker or Hard and badly noticably thinner??
Three diffrant Primary ORings? Soft, hard , thick, thin?
- Thread starter gtsun
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From what I have seen, The hard rubber ones suck. The softer ones work the best. The hard ones don't squish down and allow the cover to fully seat without cracking the mounting boss. I have a soft one on my combat and it is ages old and still works leak free. No sealant of any kind.
Thick and soft will seal much better than the hard o-ring. I'd re-use that one in a flash. The cover design uses the tiny center bolt to compress all that gasket, an engineering failure.[/quote]
The cover design and bolt are adequately engineered to apply the relatively small amount of compression to deform the O ring. It is generally the incorrect shimmimg of the supporting pillar bolt on the inner cover that causes a bow in theface alignment that most people dump silicon sealant on without realising the cause. The real engineering deficiency is the felt seal in the mainshaft cover plate. That is were most persistent primary case oil leaks actually come from.
mick
The cover design and bolt are adequately engineered to apply the relatively small amount of compression to deform the O ring. It is generally the incorrect shimmimg of the supporting pillar bolt on the inner cover that causes a bow in theface alignment that most people dump silicon sealant on without realising the cause. The real engineering deficiency is the felt seal in the mainshaft cover plate. That is were most persistent primary case oil leaks actually come from.
mick
I have found the best way to seal primary is to first ensure the cover when torqued up has the correct spacer fitted. To do this, remove all spacers between the inner and outer primary covers, fit your chosen rubber seal and carefully tighten up the primary case bolt. Now before tightening the bolt just check the gap between the cases with no preload. Then apply a very slight preload, too much and you will crack or distort the outer primary. The gap that is left when snugged it what you want to set your primary case spacers for.
Sorry for the long expalantion, but this is what works in my opinion.
Cheers Richard
Sorry for the long expalantion, but this is what works in my opinion.
Cheers Richard
I agree the set up like anything is the most important thing. This particular bike has never leaked but the P.O. Was a very experianced Norton guy & the in between guy I bought it from is a big long time Norton guy who owns more Nortons of various ages than anyone I know so when he went through it I trust he adjusted things like this. They all seem like he did. FYI. The old "soft O Ring was tow inches to long when I went to put it back. I assume from it swelling from oil exposure? I cut a bit off & made it work. Will tell if I solve my new electrical prob & get to ridding again.
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