Hi all
I have been very much enjoying my first summer of BSA ownership. 1953 B31. The gearbox rebuild proved very successful, and the mag rebuild has all but cured my hot running and starting issues. I've just returned from a 420 mile round trip to Suffolk this weekend and the bike never missed a beat. However one problem which seems to be slowly getting worse is the smoking...
It doesn't smoke from cold. It doesn't smoke when under load, nor when on the overrun. But when the engine is hot and I come to a stop at traffic lights or a roundabout it begins to emit a lot of smoke out of the exhaust! It doesn't always do this however, and I haven't worked out of there is a pattern to when it does and doesn't. As I pull away the smoke very soon clears.
My initial thoughts are the top end flooding with oil, and/or the return side of the pump not being able to pump the oil back quick enough after fast running. Oil consumption is generally quite good, so I don't think the rings or the valve guides are too bad; I also think this would cause a constant haze when moving along, but I am open to any suggestions at all!