Smokin'

Wotcha.

Here's a nice little problem for you. I bought a BSA B31 ( well someone had
to ), all very jolly apart from it has a nasty habit. It smokes. It smokes
like it is going out of fashion. This was first thought to be a loose
exhaust valve guide - so an oversized one was made and fitted. It still
smoked. Upon examining the oil tank, I found the standpipe for the oil
return was missing - this would allow oil back into the crankcase when the
engine was stopped. The back was cut out of the oil tank, and a new return
standpipe was made and fitted - then the tank was brazed back up, powder
coated and fitted. It still smoked. The bore and piston were new ( or at
least they looked new, and they measured up OK ). The piston rings were
changed, seeing as we suspected the original ones were those cheap Italian
things that have been flooding the market. It still smoked. Right - lets
take the oil pump out and check it. Seems OK - made sure the pump seating
faces were clean and free from burrs. Put it all back together and left it
overnight with a piece of glass under it. No oil at all was passing back
through the pump - so that ruled out wet sumping. Now the strange thing
is - it only smokes badly when on the side stand - which made me think the
oil was being thrown up by the flywheels and hitting the bore walls. Next
plan - a new piston. A nice new +060" piston, of reputable make , and a
rebore. Now I've put the whole plot back together again, and it still
bloody smokes when on the side stand. I'm running out of things to try. My
other B31 doesn't do this - and I can't see any difference between 'em. (
The smokey one is a 1959 alternator and the other is a 1954 dynamo )

What the Hell is causing this ?

Cheers in advance.


--
^..^ Lone Wolf
http://www.moonshiners.org.uk/

^..^ Lone Wolf wrote:
> Wotcha.
>
> Here's a nice little problem for you. I bought a BSA B31 ( well
> someone had to ), all very jolly apart from it has a nasty habit. It
> smokes. It smokes like it is going out of fashion. This was first
> thought to be a loose exhaust valve guide - so an oversized one was
> made and fitted. It still smoked. Upon examining the oil tank, I
> found the standpipe for the oil return was missing - this would allow
> oil back into the crankcase when the engine was stopped. The back
> was cut out of the oil tank, and a new return standpipe was made and
> fitted - then the tank was brazed back up, powder coated and fitted.
> It still smoked. The bore and piston were new ( or at least they
> looked new, and they measured up OK ). The piston rings were
> changed, seeing as we suspected the original ones were those cheap
> Italian things that have been flooding the market. It still smoked.
> Right - lets take the oil pump out and check it. Seems OK - made
> sure the pump seating faces were clean and free from burrs. Put it
> all back together and left it overnight with a piece of glass under
> it. No oil at all was passing back through the pump - so that ruled
> out wet sumping. Now the strange thing
> is - it only smokes badly when on the side stand - which made me
> think the oil was being thrown up by the flywheels and hitting the
> bore walls. Next plan - a new piston. A nice new +060" piston, of
> reputable make , and a rebore. Now I've put the whole plot back
> together again, and it still bloody smokes when on the side stand.
> I'm running out of things to try. My other B31 doesn't do this - and
> I can't see any difference between 'em. ( The smokey one is a 1959
> alternator and the other is a 1954 dynamo )
>
> What the Hell is causing this ?

Does it smoke from cold, or just after the exhaust has warmed up?