Filled oil tank full on 1936 model 8 350cc and now oil is coming out of the cap breather and vent pipe to chain. What is happening. I've no experience with these bikes. Help please
My guess is that the machine may have had oil sitting in the sump - wet sumping, it's called, when oil finds its way down past the tell-tale if the machine stands idle for any length of time and sits in the sump until you start it up again. If you have filled the oil tank, the excess will find its way out as you have described.
As Paul has said it's not an uncommon problem, it's not unusual for new owners of old bikes to suffer this.
it happens to Vincents on a fairly regular basis as well..You look in the tank and see the level is low and top it up. Over a period of time,6 days in the case of my 1932 9A, the oil leaks into the sump and even the chaincase if it gets as high as the crankshaft bearings. Then you have just filled the tank and start the engine and another couple of pints of oil end up trying to get into the oil tank, the next thing you know it's the Torry Canyon oil disaster all over again. On a Vincent it means it's running all over the hot engine and making a hell of a mess, on our sunbeams it's easier to clean up but still a mess..This is why you see a lot of bikes with taps in the oil delivery line to the engine, others drain the oil tank after a run,if the bike is used every day like when they were new you would never notice the sumping problems..
Regards John
Yes, that's how it is.
When my 1937 Model 9 has been standing for a while, I briefly open the drain plug in the crankcase and see if there is any oil waiting. However, my sump is relatively dry even after several weeks. I suspect that my ball valve is just still good. Only after checking that should you possibly add oil to the tank. I don't consider taps in the oil supply line to be a good idea, and I don't think they're necessary on a Sunbeam (see above).
Cheers, Thomas
Thanks everyone. Very helpful. Useful info
OK. Siphoned out excess oil from tank. Drained out the sump. And started up and all is fine and dandy. Well pleased now. Many thanks
I'm glad your sorted..
Thomas, you may not know but the earlier Sunbeam engines did not have the ball valve in the engine like yours..They relied on the tell tale closing to stop the oil flow, but the tell tale seat has no seal so it is common to have oil in the sump over quite a short period of the bike being idle.
Thank you for the write up on you engine rebuild, there are details of you engine that I was not familiar with..
Regards ...John
Yes, great that it's sorted. I understand, John, but don't know when the "late" models start. So, I expected that Mister H's 1936 model is a "later" one. And thanks for your remark about the text. I hope that it will encourage others to write down their experiences.
Cheers, Thomas