btc-er wrote:Have I got this right... the purpose of the cut off switch is to prevent fuel gravity feeding from the fuel tank into the carby and then into the motor? Does that mean that if I park so that the front is lower than the back I shouldn't see the problem?
If the needle valve was leaking would that mean that I would also be running rich?
Lucky Phil wrote:Could also be oil leaking into the cylinders. BMW motorcycles were notorious for it when left on sidestand after a good run.
Thanks for that Phil. How does the oil leak into the cylinders? And more importantly, how do I fix it?
So far I haven't been able to detect any fuel in the oil. It looks and smells like oil to me. But then, I'm an unreliable witness.
Yes - To fix the symptom you should park with the wieght of the fuel downhill. IE: nose down.
That will not fix your leaking Needle and seat though.
Basically it is designed so that as the float bowl of the carby fills the float rises and hits the needle and seat valve. In a perfect world this then stops the flow of petrol.
If your valve is leaking when it is in the closed position and you park on a hill so that the overflow of the float bowl is lower than the source of fuel. The fuel will keep trickling into the float bowl, out of the overflow, down the carby throat, into the manifold, into the cylinders, past the rings into the sump and mix with your oil.
In other words a safety cut off is a good idea. but replace the needle and seat.
Nicko