Hi to all the Experts on here; I'm intending to fit 40mm extension tubes to the manifold ports of my bike carbs (Keihin - ZZR600). This is a means of avoiding a foul between carbs inlet gubbins and the nosecone.

Tubes will be a tight, push fit on to the carb port stubs, with approx. 7mm overlap - hopefully! What fuel-compatible sealant could I use, to prevent air leakage between tube and carb port surface?

Difficult, I never did find one

You may be able to use a tank repair sealant? Or hematite red is fuel resistant

If the carb stubs are inside your extension, a PU adhesive "may" be OK if it is a very tight push fit and you are literally after a seal? And no fuel will be washing against it. but take further advice.

Is there room for a hose clamp?

Hylomar blue

Thanks for your replies, and to ReMan in particular. I'll check out Hylomar, as I can recall using it to rebuild an Imp gearbox (which I shall be very happy to never do again!!).

My go-to adhesive for most jobs is Unibond Repair Extreme.
Will almost certainly do your job but as to whether it's fuel-proof I can't say...
Cheers, Pewe10 Unibond Repair Extreme Power Glue - 20g Tube Super Glue

Hi,

I have a zetec with r1 carbs- had loads of trouble with
Air leaks and even the whole bank of carbs
Coming loose at the nurburgring!!!

I solved it by getting hold if an original set
Of the rubbers from the motorbike, and
Filing the inlet manifold tubes to roughly
Match- solved all the problems

Cheers
Les