G15 primary chain case gasket

Information relating to the Matchless G15 or AJS Model 33 750cc twin. This also includes the G15 Mk II and the G15/45
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G15 primary chain case gasket

Postby StuartN » Thu Jun 16, 2005 6:55 pm

I am having trouble with continence - of the chain case. I think the real problem is with the gasket. I managed to source a new old stock gasket from Norvils which I am sure is the correct type as all the holes are in the right place. It seems to have shrunk slightly over the years and want to sit inside the case not on the sealing land. Does anyone know if G15s used a specific gasket or it the same as early commandos, etc.

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G15 primary chain case gasket

Postby paul knapp » Fri Jun 17, 2005 2:24 am

G,Day Stuart, I have had a little success in restoring shrunken paper gaskets by pressing them in between a couple of wet newspapers, and leaving for a day or so. Check frequently to ensure they are not falling apart. I do this on a flat surface and lay a suitable weight on top to keep everything flat. If it expands back to its correct size it can be partially dried by using dry newspapers, weighted, to keep it flat.I have achieved an oil tight primary drive on my "57 Triumph, by carefully flattening both mating faces and using only Loctite Master Gasket 515, (518 is also suitable) I use no gasket where the faces are flat, but if you have distortion, use a gasket and apply sealer to both faces. Degrease all mating parts with metholated spirit, not petrol, as this leaves an oily film. I know this does not answer your initial question re commando/G15 gaskets but may be of some help to solve your oil leak.
cheers Paul.
down under

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G15 primary chain case gasket

Postby itma » Fri Jun 17, 2005 9:39 am

commandos don`t use a gasket as such, but a recessed rubber seal, bit like a large version of the one in tappet cover on singles, the wet trick works well, but use warm water and it`ll only take 15 mins to be useable. wet it don`t saturate it.
oil leaks are seldom the fault of the gasket on its own, more likely a combination of factors.

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G15 primary chain case gasket

Postby ranger » Fri Jun 17, 2005 11:17 am

I had some so called commando gaskets but they don't fit the P11/G15 - too small. Jampot spares sell the correct gasket 025037 and they seal well as correct thickness and material.

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