Smokin'

I'm guessing that this (roughly) is what your engine is like inside:

http://www.realclassic.co.uk/bsa06060800.html

 

Wotcha.

Yep - only not quite so shiny . . . . although my B33 engine will be, with
any luck.

 

Velocette singles ventilate the crankcase via the drive side main
bearing, so you're supposed to check the chain case level to make sure
it isn't too full LOL. The rate it leaked past the rubber seal made
sure it never did, of course.

So, that wasn't a bad guess on the part of the other poster; pity the
bike still smokes with no primary case in place...

Just for a laugh, have you checked what's in the gearbox, in the way
of fluids?

I'm told that bikes run on paraffin can make white smoke...and your
bike doesn't have too much in the way of other fluids that could get
into the petrol/oil....

....are you sure the petrol's not contaminated in some way? The carb
absolutely clean and free from water? No water in any filter (oil or
petrol)?

Have you taken the bike for a 20-mile run at a steady speed without
stopping, to blow all/any condensation out of the engine? This can be
tricky to ensure if the outside temp is only 5 or 6 degC. Ten miles
will only add to the internal condensation.....

HTH, but I fear it mightn't.

 

Wotcha.

Nothing in the gearbox that shouldn't be there. Besides, being pre-unit, it
would have no effect on the engine smoking.

100% sure. Even to the point that I've swapped petrol tanks. OK, not to
prove it was contaminated petrol, but I had the tank of one bike fitted to
the smokey one whilst I was sorting a petrol tap problem out. Just for the
record, it's had two different oil tanks on it as well.

A nice 60 mile run over to Malvern last Saturday - and around the same
distance back.
I'm currently waiting for a new oil pump to arrive - let's see what that
will do.

As a certain supermarket is fond of saying "every little helps" ;-)

Cheers.

 

A hawkish eye spots no mention of the carburettor.....but I'm sure
you've looked at that too.....e.g water/mayonnaise/goo in the bottom
of the float bowl that only reaches the pilot jet at a certain
angle....

 

Wotcha.

A hawkish eye would also have spotted that I sent the repy to your email
rather than the newsgroup - this is what running SOBs does to you ;-)

It's most certainly oil smoke. Blue / white in colour, and smells like oil
smoke.
I've been out on the bike this evening, and as long as it is kept upright
there is no visible smoke.
I reckon the easiest way to "solve" this one is to bung a sidecar on the
thing.

Cheers.

^..^ Lone Wolf - pressing the wrong button, as per normal.
http://www.moonshiners.org.uk/

 

By Jove I've got it! It's actually a K100!

 

LOL.

Some things spring to mind, but I'm not that familiar with that
particular engine so might be off the mark here.

Are all the engine parts for that particular engine? There have been
many instances of similar engines having different internals that
don't work well together, e.g. a later mod that wasn't designed to be
retrofitted.

Is there any place in the cylinder-head where oil could pool while the
bike is vertical, yet flood e.g. a valve-seat when on the propstand?

In similar vein, is the scavenge-point in the crankcase in the right
place? It might not be picking up enough oil when on the propstand
until it pools to the right level, which by this time the flywheels
are flinging gaily into the bore at ten times the normal rate....those
later-fitted baffles were put there for a reason....

Looking at the pix of the BSA engine in the link posted earlier, the
pump will be on the 'high' side of the crankcase when the bike is on
the propstand, allowing oil pooling in the drive-side half. I suspect
this is your problem - either the pump isn't clearing it properly, or
the flywheels are flinging too much into the bore (wrong flywheels or
no baffles).

 

Wotcha.

To the best of my knowledge, nothing dramatic was ever changed during the
entire production run of the "B" group pre-unit models. The later ones were
alternator and coil ignition, as opposed to magneto and dynamo, but the
crankcases on the later ones still had the mag-dyno pedestal cast into it.

'fraid not. In fact, the oil will drain from the head better when on the
sidestand. There are new guides in there, so I know that part is good.
I've even swapped heads with a non-smoking bike just to rule that one out.

That is what I think is happening - but I'm at a loss as to why.
Another reason I think this is :--- If you kicked the bike over with the
cylinder head removed you could see oil start to pool on the crown of the
piston - and it even started on the left hand side. Now this was done with
the "old" ( for old, read new, shiny, +.040" piston ) piston fitted. The
barrel had recent honing marks, but did seem well polished in places, hence
the rebore and new + .060" piston that is now fitted.

I extended the pick up point for the oil pump last weekend, thinking that it
would scavenge before the level built up to the flywheels ( assuming that is
what is actually causing the problem ) - and it made virtually no
difference. I'm still waiting for a new oil pump to arrive.

Cheers, yet again.

 

I must say I find this one of the most compelling threads in this newsgroup
in quite a while, even though on paper it would seem like a bit of a
no-brainer. Feels like one of those head-scratching gatherings in the shed
over mugs of tea and [optional] Woodbines that we've probably all done at
one time or another.

I shall feel a bit sad when it's finally sorted!

 

Don't forget the marmite sarnies.

 

Wotcha.

The scratching continues.
I'm running around on the bike, mainly because I just love riding it, and it
does just what you'd expect of a low tune ( around 17 bhp ) old cast iron
single. No excess smoke at all when riding, but the moment you stop and
unlock the garage . . . . the road disappears. I even have to make sure the
neighbours have not got the washing hanging out. The thing doesn't even wet
sump - I can leave it a week or more, start up and ride off without fogging
the street.

In a way, so will I, but something else will crop up.
The amazing pinking Enfield was the last little mystery - that was finally
tracked down to the piston manufacturer not having the best quality control.
They 'forgot' to machine the best part of half an inch from the crown. We
reckon the compression ratio must have been somewhere around 13:1 or more.
EEEK.
http://www.moonshiners.org.uk/bullet.htm#headoffreturn

It's just BSA's way of seeking attention ;-)

 

I'd watch out for security bolts in the rear rim, as well. The Brits
seemed to put the bloody things in bikes at random.

 

Wotcha.

For some strange reason they were fitted to my old Super Rocket.
Many moons ago, I'd just fitted a new TT100 on the rear and bunged the wheel
back in the bike. Being an idle sort of a chappie, I thought I'd kill two
birds with one stone and blow the tyre up at the local garage at the same
time as filling the tank. All went well until I rode home. Something was
going thump, thump, thump, in the vicinity of the rear wheel. Ah - I've
felt this before. A spoke has broken and fallen across the sprocket,
causing the chain to 'jump'. I was wrong. I got back to the garage and
looked. Bloody great - a new tyre, and there's a great big bulge on the
wall. Time to remove it and take the thing back to the shop. Right - wheel
out. Security bolts undone. For some reason, I could only find two of my
three tyre levers, so I struggled on with just the two and before long I had
the tyre off the rim . . . . . only to find tyre lever number three was
happily nesting inside the rear tyre. Ooops.

p.s. the B31 is still smoking - I even pulled the top end off the engine
again this morning, just in case I'd missed anything earlier. I do like
these engines. Less than half an hour to take the complete top end off, and
put it all back together again. Sadly, rain stopped play later in the
afternoon, but I did manage a good two hours of riding around.

 

Thus spake ^..^ Lone Wolf () unto the assembled multitudes:

That's just as well, seeing as you're becoming ever more intimately
acquainted with them! ;-)

 

Wotcha.

It's just practice for when I pull the B33 engine apart.
After a few more years of this, I may be ready to try an engine with more
than one cylinder ;-)

 

Wotcha.

I just *knew* those piston rings on the kitchen table were off something.
;-)

 

Fucked or broken or wrong size oil control rings.

 

Wotcha.

It's now on a brand new piston & re-bored barrel.
Rings were what the previous owner must have thought too - it had a brand
new piston and a re-bored barrel when I bought it . . . .isn't hindsight
wonderful ;-)
I thought the 'original' piston must have been one of those nasty Italian
jobbies, with rings that never bed in - so I obtained and fitted some
Hepolite rings. Next move was to buy a "known good" piston and have the
bore done to match. Seems that was what the previous owner had done.

Ah well - these things are sent to try us.

Cheers.

 

Still, you'll have all the spares you need if it ever seizes.