Mk 3 primary chain case leak

Struggling for ideas.
Trying to fix a primary leak at the very bottom of a MK3 chain case.
Cases seem in good nick.
PO had fill the bottom centre hole with gasket goo and put a washer under the screw head.
I've stripped and cleaned all the crap, new gasket, carefully put back together.
Small leak from area of screw.
Stripped again, re cleaned, tried a careful amount of gasket cement in threaded hole.
Back together, new gasket. Same leak, very small but annoying.
Any ideas appreciated.

(1) Take the primary case cover off and put on smooth, level surface, Get a magnifying glass, and look for warping, hairline cracks and tiny dings in the problem area.

(2) Learn to live with it.

I have this too, on a mk3. I may try a Dowty washer next oil change.

peter12 said:

Trying to fix a primary leak at the very bottom of a MK3 chain case.

Small leak from area of screw.

Click to expand...

Presumably, the leakage is from the screw hole, not the gasket joint as the inner case gasket face is very narrow there.

Clean the oil off, then spray the area of the leak with a powder-type deodorant spray, or foot powder. The deodorant will leave a chalky white, easily removed coating on the surface; the source of your oil leak will be clearly revealed.

You could try a Cometic Nitrile rubber and aluminium gasket on there. I always had a bit of oil on the bottom of the primary joint until the Cometic was fitted. It as dry as toast now. The cover has been off and on using the same Cometic gasket twice now, once for new clutch plates , then again for a good inspection of the primary chain. The primary cover sealed right up perfectly each time.
I'm sorry, I have quite a few Cometic part numbers but seem to have misplaced the number for the primary gasket. If you call them, I'm sure they will find it for you. You will only need one gasket, it will last forever from what I've seen.

Glen

Thanks for your replies. I think I be covered most things. I might try the re usable gasket but not convinced that's the problem.
I had the same with a 750 I work on, 3 new seals still leaked.
When I looke carefully and cleaned out old gunk I found a blow hole in the cover bypassing the rubber seal.
Was hoping to find similar but havnt so far.

Reach out to Jim Schmidt and get one of his Fiberglass reinforced silicon gaskets for the MK3 primary. Solved my issues with a leaky mk3 primary.