Oil leak when clutch pulled in

[nzmarty]

Hi there.  I have acquired a '54 B33 500 in good running (riding) condition, but whenever I pull the clutch in oil pours (yes pours) from the bottom of the gearbox.  It otherwise doesn't leak, and th leak from the clutch pull stops as soon as I release the clutch.  I presume the 'expert' who overhauled the engine prior to my taking possession forgot to fit, or damaged when fitting, a pretty substantial seal.  Questions - is this common?  Is the seal accessible with the engine fitted (i.e. hopefully don't need machining to fit oversize).  Where can I get parts?  I am new to BSA, so please be gentle.

[Greybeard]

Hi Marty?
This forum is for A7 & A10 machines but I'm sure someone here can point you in the right direction.

[chaterlea25]

Hi,
From your description it sounds like the bolts and screws holding the gearbox together are either loose or
threadbound so not clamping the cases together properly????
Pulling in the clutch then forces them apart 

John

[KiwiGF]

Hi Marty, where in NZ are you? The reason I ask is that there is a good club on the nth island you can join and get help from fellow BSA owners (I used to be the secretary until recently).

 See http://www.bsa.org.nz

There is a smaller and very active club in Christchurch, and another in Dunedin.

[nzmarty]

Cheers for that - I will make contact with them. I do seem to have discovered the origin of the oil. The bike has been sitting post engine overhaul for a couple of years. Would appear the crankcase oil has slowly levelled across into the gearbox case over time. Have drained the gearbox of a couple of litres of oil, which happened to be how much the engine was low....

[chaterlea25]

Hi
Thats an unlikely scenario?? unless major modifications have taken place
The engine oil could drain into the primary case ok but will then leak out onto the floor once the level reaches the primary case sliding plate, that only has a felt seal to the atmosphere
The gear oil would normally leak out along the gearbox shaft onto the floor if the gearbox is over filled

Maybe the box was over filled as the bike was going into storage?
All this still does not explain why oil leaks out when you pull in the clutch????

John

[BSA_54A10]

Sure sound like Bu** **it to me.
To do that , the primary needs to fill above the level of the main shaft then leak back down the space between the main shaft and the output gear sleeve bearing without first leaking out of the slidding plate which is around 1" lower.
Or the oil could flow back through the main shaft in the cavity between the hollow main shaft & the pushrod.
Again the sliding plate would be lower, unless yours is a bolt up box with a primary chain tensioning slipper, but if the primary was that full of oil, there would be nothing left in the engine and there is no way the clutch would work unless fitted with a modern fully wet clutch.

[nzmarty]

All great advice - I will be taking the cover off and seeing what I can find.

[Rocket Racer]

Further to KiwiGF plenty of BSA support in NZ, if you're Auckland based, send me a PM, I've run a plunger B33 for over 30 years 
Great bikes, totally bullet proof, its why there's no forum for them, they don't break.

If its leaking that badly get someone to hold in the clutch while you crawl underneath. Big leaks out of the box are extremely unusual.
Being a swing arm bike the boxes are at least the common to the A7/A10 pre unit motors.

Auckland club nights on Wednesday this week 
Tim

[nzmarty]

Thanks Tim I will do that. I'm in Cambridge so won't be able to make the Auckland meeting but will PM you soon. Cheers

[Mark_789]

There is b50.org covering all bsa and triumph singles, apparently it's good although I've not looked as I don't have one (yet).