Chaincase leak from Shock Absorber Cover

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
Andy E
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Chaincase leak from Shock Absorber Cover

Post by Andy E »

Ref my 1956 AJS 16MS

Hello again. I'm now tackling the second of two oil leaks on my bike. Oil is leaking from the circumference of the joint between the two pressed steel sections of the chain case, in other words between the smaller domed section that fits over the engine shock absorber and the main body of the chain case. Can anyone recommend a product to run into the joint between these sections on the inner side of the chain case? It's a shame that I had to strip this apart as the rest of the chain case was oiltight!
Brad
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Re: Chaincase leak from Shock Absorber Cover

Post by Brad »

Hello Andy
I had a similar problem on my G80 and while I had the chain case off for other work. I cleaned the area with plenty of brake cleaner and ran some two pack epoxy resin around the inside joint. I used Gorilla Glue which I have used for many jobs and found it very good. I don't know how long it will last, but after several hundred miles, the dome is still tight with no sign of any oil weeping out.
If it ain't broke, fix it till it is. ;)
Andy E
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Re: Chaincase leak from Shock Absorber Cover

Post by Andy E »

Hello Brad

Thanks for that. I had wondered about using a two part epoxy, and it just so happens that I have some of the very same Gorilla Glue at home. I've ordered a new later type chain case seal and new cork gaskets from the spares scheme, so hopefully I'll get the bike back together for the weekend.
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thornebt
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Re: Chaincase leak from Shock Absorber Cover

Post by thornebt »

Hi. I followed someones advice on this forum to use tallow to seal the bottom of the chaincase. Just put a thick smear on both sides of the lower halves of the chaincase (the tallow is the consistency of slightly warm candle wax), fit the outer chaincase with the seal / metal band and gently use a heat gun to warm the bottom half of the chaincase but not enough heat to damage the chaincase paint or rubber band. It worked a treat and I do not get any leaks from the chaincase now. I cannot guarantee that this is the tallow sealing the joint, it could just be a very good joint and rubber band. But I think the tallow is responsible for it being leakproof.

The main thing, of course, is to get the two halves to fit as close as possible to start with! Cheers. Bruce.
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thornebt
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Re: Chaincase leak from Shock Absorber Cover

Post by thornebt »

Thinking about it now I seem to recollect that I did the stuff with the tallow and heat gun and then fitted the rubber band and metal sealing strip afterwards. The memory is not as good as it used to be! Cheers, Bruce.
Andy E
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Re: Chaincase leak from Shock Absorber Cover

Post by Andy E »

Hi Thornebt

I must admit that I wouldn't have thought of tallow. Presumably it's melting point is above the max temperature experienced in the chain case. I was thinking of using silicone sealant between the case halves which is what the previous owner had done. Any idea of where I could pick up some tallow?
SPRIDDLER
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Re: Chaincase leak from Shock Absorber Cover

Post by SPRIDDLER »

Andy E wrote:Any idea of where I could pick up some tallow?
Loads if you Google 'Tallow'. Some pure organic beef tallow too. But this looks about right......



But I understood from your post that it was the s/absorber cup that was leaking, not the chaincase halves....... :?
For sealing the chaincase halves the club seal has had some rave reviews
(Should we get out more?).
'There is a tide in the affairs of men
Which taken at the flood............'
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Rob Harknett
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Re: Chaincase leak from Shock Absorber Cover

Post by Rob Harknett »

Ages ago I noticed the little drive sprocket dome was loose on one of my bikes. Have to fix it some time........ Ages later I remembered about it being loose, but found it tight. Don't ask me how it tightened, rust perhaps?
Used Tallow years ago as a release agent on heat press's making wrap round TV & Radio cabinets. ( glued veneer sheets, clamp in the press, heats cures glue, resulting in rounded corner plywood TV cabinet body ) smelt like roast Beef in the factory, smelt awful if it was rotten.
Andy E
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Re: Chaincase leak from Shock Absorber Cover

Post by Andy E »

Yes, the leak is from the shock absorber cup. I just want to make sure that I don't end up with any other leaks from the chain case which was oil-tight before this leak developed. I have ordered a new club seal and will be using this. The previous owner had used silicone between the chain case halves and I have been thinking of doing the same as the inner case is very slightly distorted. Might the new seal be able to deal with a less than perfect mating face between the two halves without using a sealant?

.
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dave16mct
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Re: Chaincase leak from Shock Absorber Cover

Post by dave16mct »

'Might the new seal be able to deal with a less than perfect mating face between the two halves without using a sealant?' (Quote.)

Yes that's what it was developed to do.
Dave.
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