by Fil » Fri Aug 10, 2007 4:20 pm
I had a problem with my carb overflowing after I put the old girl back on the road after a long (too long!) lay-up.
I ended up stripping the carbs as the jets were gummed up and the problem has been cured. As Basser says, it's almost certainly down to the needle attached to the float not closing properly. If this happens, fuel will just run out of the tank, into the float bowl and out of the overflow. What should happen is that the float bowl fills until the float pushes the needle against it's seat and stops any more fuel entering the float bowl.
The reason the needle isn't seating is probably due to either:
- Float height is set wrong (doesn't close needle until the fuel has reached the overflow)
- Float is leaking (ie it doesn't float anymore as its full of petrol instead of air!)
- Float/needle is sticking (can be cured by cleaning float chamber, needle and seat.
Try giving the float bowl a sharp tap with a soft faced mallet next time it overflows - if it stops overflowing then chances are it's a sticking needle.
Unfortuantely all of the above will require you taking the float bowl off the carb as a minimum. I'm not sure if you will be able to do this with the carbs on the bike, and they're a beeeeeaaatch to get off!!