Hi all. Started up the bike tonight to see how the temp exhaust system sounds (thanks Greg), and I notice a load of fuel leaking out. It's leaking out of some sort of tube the sits between 3 & 4 - there's a corresponding one between 1 & 2. It was running out quite freely, but now is between a slow irregular flow and a heavy drip, if you get my gist.

It looks like some sort of overflow, there's a tube that runs between 1 & 2, and another between 3 & 4, with the outlet pointing down between the trumpets, forming a T. Don't have a camera at the mome, will endeavour to get a pic soon.

Any thoughts? Got a race next weekend, keen to get this sorted.

Pleiades wrote:Hi all. Started up the bike tonight to see how the temp exhaust system sounds (thanks Greg), and I notice a load of fuel leaking out. It's leaking out of some sort of tube the sits between 3 & 4 - there's a corresponding one between 1 & 2. It was running out quite freely, but now is between a slow irregular flow and a heavy drip, if you get my gist.

It looks like some sort of overflow, there's a tube that runs between 1 & 2, and another between 3 & 4, with the outlet pointing down between the trumpets, forming a T. Don't have a camera at the mome, will endeavour to get a pic soon.

Any thoughts? Got a race next weekend, keen to get this sorted.

The carb float scticked. Having same issue twice....

Also check float valve and hinge pin

common problem... check your float valves and seats for wear and replace if you see wear on the valve... I do mine yearly. Allens Performace stock parts.. if stuck, send me a PM, as I may have some spare. Col

Cheers guys. Will try to get them apart over the next couple of days, will let you know the outcome.

Well, pulled the carbies off, floats all looked OK, so put her back together again. Started it up, let it run till it was warm, and all seems good. None of the floats appeared to be stuck or anything like that, so not really sure what I did.

you prob cleared what ever was stopping the valves fully closing... be aware it might and most prob will come back.. just gott make sure its clean in there and your fuel, lines, filter etc are all clean... I say this is from experience.. :) cheers

yeurman wrote:just gott make sure its clean in there and your fuel, lines, filter etc are all clean...

Filter? Oh, I have one of those. It's in my spare parts box. Should get around to fitting that. And perhaps an airbox...

I have the same problem on my nc23 but between carbs 1&2.The overflow is heavily dripping.


I opened the carbs again and again.Floats seems ok,no holes or anything.dont know how to check the needles though.

BY THE WAY my valve clearances on cylinder 1 are out of margin.The gap is smaller than it should be,I would like to think that this is the problem ( which is easier to repair )