Author Topic: B31 oil leaks  (Read 801 times)

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B Murphy

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B31 oil leaks
« on: 18 June, 2020, 20:41:29 »
Hi all

I have the urge to try and make my B31 oil tight. This is my first B model, has anyone completed this work? is it possible to make them oil tight? or will I be wasting my time and still need to place a tray under the bike after every ride.

Bob

idie

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Re: B31 oil leaks
« Reply #1 on: 18 June, 2020, 21:36:12 »
You might get it oiltight but when you stop it will drop some oil out of the breather. You will need a small catch container attached to the breather pipe.

Jim S

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Re: B31 oil leaks
« Reply #2 on: 20 June, 2020, 12:57:38 »
Hello B. Murphy
The older configuration gearbox spews out oil if you put 1 pint in per the BSA recommendation. See this post for more info:
https://www.bsaownersclub.co.uk/bsaoc_forum/index.php?topic=8337.0

For the primary, put in the minimum amount of oil. The level should just touch the bottom of the chain. On my C11 I have stopped putting oil in the primary and periodically lub the chain with rear chain lub. Ensure the clutch bearing has grease however.

For the engine, it is best to do some investigating to determine the source.

Christouring

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Re: B31 oil leaks
« Reply #3 on: 26 June, 2020, 22:01:52 »
I am sure BSA company invented Whack-a-Mole.

Agree with posts- under fill gearbox. I run without primary case oil and spray chain lube direct periodically. Make sure clutch centre bearing is well greased.
Breather WILL drip!

B Murphy

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Re: B31 oil leaks
« Reply #4 on: 26 June, 2020, 22:09:08 »
Thanks, yes most of the oil is from the primary side. I'll let it run dry and keep the chain and bearing lubed. Doesn't the clutch mind being without any oil, is the oil in there to just slash about and keep the chain oiled up?

JulianS

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Re: B31 oil leaks
« Reply #5 on: 26 June, 2020, 22:49:42 »
Oil in the chaincase also lubricates the cush drive assemble for the engine sprocket. If you do decide to leave the oil out remember to lubricate the cush drive.

B Murphy

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Re: B31 oil leaks
« Reply #6 on: 30 June, 2020, 18:09:52 »
You might get it oiltight but when you stop it will drop some oil out of the breather. You will need a small catch container attached to the breather pipe.

Has anyone made one of these catch containers? photo's if possible please.


Mike40M

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Re: B31 oil leaks
« Reply #7 on: 01 July, 2020, 05:53:43 »
The only catch tanks I've seen on BSAs are on a couple of pre -47 classic race B33. Beer cans fastened with Ty-raps.

EDDIE SIMPSON

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Re: B31 oil leaks
« Reply #8 on: 01 July, 2020, 22:46:39 »
if you can keep the primary drive oil leak proof you could use that as a catch tank from the breather and in a top corner run a breather pipe to the rear mudguard. it was the method race teams used. however the engine oil seal will have to seal against the chaincase as with triumph units.