Oil Leak

[OldChuffer]

Almost finished the restoration of my first Brit bike (after restoring a score of Jap bikes). Put some oil in yesterday and all seemed good but then today i noticed it was leaking oil, i know Brits do tend to mark their territory but i think a drip every 10 seconds is too much.

I cant see where its coming from due to the frame plate underneath but its coming out where the rear oil drain bolt is. The drain bolt looks ok and the bike hasnt been started. I'm guessing its an engine out job again to investigate further, any comments or suggestion on where to look first? Thanks

[clive]

Oil has a tendency to run to lowest point which is probably the drain plug. Friends have used talc to try to track it back. Blow it on especially with an unused emgine and it may stick on the places that the oil has run down. Personally I just put up with it but not a drip every 10 secs! Good luck.

[SPRIDDLER]

Can't really help much as I'm not up on L/W's and it could be coming from several places, however if it's clean oil it's likely to be
coming from the gearbox/chaincase rather than the engine.
EDIT. Ah, just realised that all the oils will likely be clean as it seems that you haven't run the engine yet.

[OldChuffer]

So if i support the bike off its main stand do you think i'll be able to remove the lower frame tray to have a look? Is that possible?

[Rangy65]

If you have changed the oil recently some will have spilt into the channel - it could be this that you are seeing. Use some degreaser and flush through with a hose pipe let it dry and then see if you still have a leak.

Also if the crank cases have been assembled ensuring the mating sufaces are good and using a decent gasket sealent they are pretty leak proof.

It more likely that any oil is escaping from the gear box - loads of threads on this.

Removing the lower channel can be done but its quite a job as the footrests, foot reast bar and main stand need to be removed.

Cheers

Steve

[OldChuffer]

Thanks all for the advice, i managed to get the bottom frame member off, stand and all, by putting the front in a paddock stand and the rear on a car ramp. Indeed the leak is coming from the gear box, so once i've read the workshop manual about the gearbox i will take the outer cover and inner cover off and reseal it whilst its in the bike. Thats the plan anyway.

Another question, the manual mentions a gasket, is this neccessary or will Wellseal do the trick?

[clanger9]

It may well be leaking from the output shaft seal.
It's also possible that the little pin to secure the layshaft bush is missing (on later gearbox casings).
Wellseal works just fine for the gearbox casing - the gaskets aren't essential.

Some more info here: https://www.ifixit.com/Guide/AJS-Matchl ... 77#s171906

[OldChuffer]

Thats great, thanks very much for the link.

[OldChuffer]

Ok i got the outer cases off pretty easily. I was hoping the gears would stop in place while i resealed everything but no, cogs etc went everywhere. At least the ball bearing stayed where it was . So your document will be really useful as i might as well give it a good going over while i'm in there, we're still on lockdown on Anglesey so i can take plenty of time. Will be good to learn anyway. Thanks again, much appreciated.

[56G80S]

I rebuilt one of these soooo many years ago. I wish I had the ifixit guide then, it seems really good.

I'll have to see what else is on there.

Johnny B