oil being pumped out of breather

[dave p]

hi chaps, we could do with some advise, brought an a10 the engine had been rebuilt, few bits and bobs wanted doing. all done. started the bike, found oil returning to the tank but after about 30secs oil pumped out of the crank case breather. any advise would be most helpful. thanks in advance dave

[t20racerman]

As a first check, take of the timing cases and check that the timed breather has a cork washer in place and that it is not loose.
How much oil though? I had some badly worn barrels once and lost about a pint every 100 miles!

[BSA_54A10]

usually it will be because the corks behind the breather valve are not thick enough ( there should be a slight drag ).
With new engines it could also be because it has a sump full of oil, try draining the sump the starting again.
Also with a new bore it can be due to excessive blow by because the rings have not sealed to the bore yet.

[dave p]

just an update on the oil problem, drained oil out of sump, then started the bike, it ran for couple of minutes with oil spurting out of return pipe at a good rate, then oil pumped out of breather, and could watch the level going down in the oil tank as its pumping back.  sorry at the start we checked the cork breather and fairly tight fit, as pre advise before. does this give anybody a clue. regards dave.

[chaterlea25]

Hi Dave P,
There are probably several things to check??
""Rebuilt engine""
Has the oilpump been overhauled??
Has the builder been over generous with the gasket sealant?
I would remove the sump plate and check for crap in the sump and in the suction pipe going to the pump
Is the suction pipe tight in the crankcase?
If theres a magnetic sump plug fitted is the magnet positioned AWAY from the pickup pipe??
I have seen the ball held shut by an over strong magnet
Check for any restrictions in the oil return pipe, and the one inside the tank
Have the correct rocker oil feed bolts been fitted? these have a very small restricting hole in them, same type bolts with much bigger holes used on B31/33  oil drains and Goldie rocker feeds
Has an inline filter been fitted? is it connected correctly??

The list could go on

HTH
John O R

[dave p]

hi, john o r, i am a triumph man and iam helping out with this bike, and one question is can the pump be built back to front as it seems to be pumping more than its scaviging. other points will be looked at .regards dave.

[chaterlea25]

Hi Dave P,
I dont believe thats possible
Its a lot more likely that theres something restricting the return?

Cheers
John O R

[Dutch]

I had that happen once but it was 35 years ago, I think I pulled the covers off, scratched my head had a beer, and put it back together and it was fine.....!....?
ps It was veery slippery at the traffic lights, otherwise I'd 've kept riding!
 oh yeah ,why I'm here, by the way, is I'm fresh on the scene too and after info on 67-4036 the little Front engine plate insert for Plunger A10. I just bunged in a bit of tube to fit but figure that I need to check the correct width of it, as'm having trouble with wheel alignment and possible(slightly) bent frame. If anyone doesn't mind having a little measure(between frame lugs,or any other reference points is fine) I'll appreciate that, and in the meantime figure out how to ride this show properly???
                                                      cheers, Dutch

[wilko]

They all do that sir! If the ball gets stuck in your return line at the bottom of the sump plate. Get under there and poke and clean the  tube until it's free of glunk.

[dave p]

chaps, just an update onthe a10 problem. found as engine been stood for few years (as wilko stated the ball in the scavenge pipe was stuck) now oil flows back to tank. thanks for all replys. regards dave