Primary Case Seal Driving Me Nuts

olympus said:

Am I missing something.

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Only that the castings vary, so some like yours and mine are as they should be but other present challenges

maylar said:

My buddy George thinks the same. "It is what it is".

One day he called me to have a listen to some rattle noise coming from his primary. We pulled the cover to find that the o-ring was not seated in the groove. All the ATF had leaked out. Primary chain was rusty and stretched to the point of dragging on the inner chaincase. Just sayin'

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When the left exhaust stops smoking on start up I top up the primary. Seriously though, I keep an eye on it thanks.

That is a novel way to monitor the oil presence in the primary. I used to do that also until I bought the new gasket. Now I have to pull the screw out.

Back on about the primary ö"ring. I always reuse mine and silicon them in place. Saves the hassle and doesn't leak.

In over 45 years of owning my Norton I have never had any problems fitting the rubber seal in the groove of my primary I have replaced the seal 4 times in those years I have never put any sealant or anything to hold it in place, been using ATF type F for about 20 years without any problems but the rubber seals do need replacing after sometime of being removed for servicing and clutch inspection/maintenance, I never over tighten the centre bolt and have never had any leaks from the primary case, maybe I just have a freak of a Norton that don't leak, most of the time the rubber seal stays in the groove when removing the case.
I have found most after market parts are not the same size or thickness and maybe that is your problem why its not staying in the groove and if the rubber seal came with a engine gasket rebuild kit then that could be the problem as I have had a few gasket kits where timing gaskets did not fit properly and maybe the rubber seal is the same and the seal not the right thickness, as it should be a tight fit in the groove when new and should stay in the groove when removing the outer case.

Ashley

Toronado .... refer back to your posts from April 2 2020 , tips on leak free primary chain case sealing , maybe start again ..... I feel your frustration