Incontinent alloy chaincase

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Incontinent alloy chaincase

Postby Dave T » Sun Aug 25, 2019 6:55 am

The title says it all really! Help! When I fill oil in my 1959 G80 chaincase to just touch the chain it is widdled out , leaving big puddles 4" wide or more when I stop, oil along the rear of the bike and nicely lubing my tyre! When the level drops to about a quarter inch below the chain, i.e. no longer of any use in there, it stops leaking and behaves itself. The crankcase breather breathes and with the big fill hole cover screw removed there doesn't seem to be any blowing from it even revving the engine. I'm at a loss and am due to go away on it in a week but don't want to ride either dumping oil and filling it every day or riding with the chain and clutch dry!
Any ideas?
Dave.

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Re: Incontinent alloy chaincase

Postby Mick D » Sun Aug 25, 2019 11:06 am

Hi

You need to identify the source of the leak, thoroughly clean the inner and outer cases and re-fill with oil.

Let it stand for a few hours then check for evidence of leakage along the joint between the cases or from the drain / level plugs. - If no leaks:

Run the engine in neutral for a couple of minutes, check for leakage from the vicinity of the main shaft, the access hole for the alternator cable, the breather hole in the same vicinity, the boss where the central bolt locates the inner case. - If no leaks:

Run the engine in neutral for longer and observe the above areas until you see where the leak is coming from.

There's a slim chance the inner chain case to crank case joint may be at fault but not likely - the other possibility is a cracked chain case, (hopefully not).

Regards Mick

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Re: Incontinent alloy chaincase

Postby Dave T » Sun Aug 25, 2019 12:37 pm

Food for thought Mick, thanks! I definitely need a bit of method in my madness so I'll stick it on a big sheet of cardboard and run your suggestions, cheers.

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Re: Incontinent alloy chaincase

Postby bob121 » Sun Aug 25, 2019 3:26 pm

A friend said to me the other day regarding the locating the source of leaks, that using talc where the possible culprits may be is helpful. It will lock the trail of oil back to its source more often than not. It's no fun leaving puddles wherever you park. I had a run down to the south coast the other day. I parked up twice and had to wipe the bike down in an effort not to leave too much of a mess. And when I got home, my feet were covered. Not happy.

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Re: Incontinent alloy chaincase

Postby Dave T » Sun Aug 25, 2019 4:05 pm

That's a good idea, thanks.
Amongst all the things i've done in desperation is gently poked a thin wire up the crankcase breather pipe and it went "click" so I think it may have been stuck leading to venting in the chaincase and blowing the oil out. I took the chaincase cover off and fitted a "Grommit" on the alternator wire which I'd neglected to do when I changed the alternator! AND I've put 50 grade oil in there, not the ATF I'd been using.
Just been for a tour around for half an hour, it's 33° here and it's not dripping as much at all, just a few "ordinary" drops so if I've cured it I don't know what I did!!
We'll see, thanks for the suggestions.
Dave.

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