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Hello everyone, a while back I got online and asked about a problem I have with my 1957 500 Dommie. I've not been able to sort it out yet.
Basically I rebuilt the top end, springs, valves, guides, rings, gaskets, the usual. At first start up though, an odd thing happened, exhaust smoke started coming out of the oil tank. I have taken her for a ride after tuning the new clutch in today, and she is running like a dream, except that the smoke at higher revs is forcing oil past the oil tank cap seal and out the breather tube. The oil is frothy too, I assume from having smoke blown through it. Does anyone have any ideas? Thanks in advance!! Boaz
Check your crankase breath…
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Check your crankase breather pipe is clear (not blocked). Returning oil to the tank contains lots of air ,so is frothy, Tank only needs to be half full. Tank needs to breathe ,usually to the rear chain ,check pipe not kinked. Smoke could be water vapour?, Motor may need 1500 miles to run in during this time may breathe oil out more than you like!. Also smoke from burnt oil drawn through with the returning oil.Compression should increase with miles and blowby less. As long as rings fitted right.