Leaky float bowl

[MSTRS]

I have a problem with a leaky float bowl. The rubber 'O'ring-type gasket just doesn't seem to seal properly. I'm thinking that it needs assistance from some sort of paste/gel gasket goo. Is there a fuel resistant one to be had? Alternatively, a friend of mine suggested smearing the rubber gasket with Vaseline. Anyone....?

[TLDV8]

I would check the gasket surface to make sure it is flat,have heard of warping before today.About the only thing truely fuel resistant is Three Bond as far as sealants.There would be a mechanical reason for it not sealing if the rubber gasket seems fine.You could try fitting the bowl with no gasket to see if there is any warpage maybe.

[MSTRS]

Bowl is not warped (thought of that and checked) or at least not visibly warped. Unlikely to be the carb body. Had fitted a new o-ring as well. Poor design in this case means 2 bolts only hold the bowl on, not 4 as is more usual. Who stocks Three Bond and is it a hard set type (ie hard to remove) in case this also fails?

[Motu]

Orange silicon - lay a really thick bead or you won't get the proper effect.

[Paul in NZ]

I'd also check the float needle is sealing OK. Possibly the float level has risen too high etc?? Ususally it's below the joint so if it's leaking when parked that may be the problem.

[Motu]

Obviously the seal is not compressing enough to make the seal - so it's either shrunk and gone hard,or it's just plain not up to the task through poor design.

Hylomar is a fuel proof sealant....but I have used windscreen grade urethane,carefull, it does more than seal...it bonds very well too....

[MSTRS]

I'd also check the float needle is sealing OK. Possibly the float level has risen too high etc?? Ususally it's below the joint so if it's leaking when parked that may be the problem.

Side stand only and it is #1 carb (downhill side) - I would think that the fuel level would put it above the joint when parked

[MSTRS]

Obviously the seal is not compressing enough to make the seal - so it's either shrunk and gone hard,or it's just plain not up to the task through poor design.

Hylomar is a fuel proof sealant....but I have used windscreen grade urethane,carefull, it does more than seal...it bonds very well too....

New seal. Not too keen on 'permanent' bond if can be avoided. What is/where from this 'Hylomar'?

[Motu]

New seal. Not too keen on 'permanent' bond if can be avoided. What is/where from this 'Hylomar'?

So it's a faulty design,not enough ''crush'' on the seal.Is this an OE seal? We have been having trouble these last few years with locally made rocker cover gaskets,they harden and shrink very quickly,leaking about 2 months after fitting,so now it's only OE for me.You may have to ''help'' the seal sit a little higher for the correct crush.But it's not designed to seal holding a liquid - the float level must be too high.

Hylomar is an ancient product,rumoured to come from the caldron of Getafix the Druid himself.It was the recomended sealant for Rolls Royce engines,and is excellent for alloy/alloy joints. 35 yrs ago it was a secret known to few...I used to get it from my friend who worked for Fodens,they used RR engines.

Now you can get it from Repco.

[MSTRS]

Thanks Motu - will report back when resolved...

[MSTRS]

Hylomar applied. Bike run for 10mins or so to get it all warm. 3hrs later - no leak apparent.:woohoo: Hopefully it will be one of those 'fix and forget' jobs

[F5 Dave]

Well sometimes a good idea to fix & think.

So this is the gasaxe with no pump & a gravity fed vacuum fuel tap? That may also be leaking. if it is it will flood that cylinder & foul the plug every so often. Just something to consider. If it does the taps can be tweaked to seal again.

[MSTRS]

Well sometimes a good idea to fix & think.

So this is the gasaxe with no pump & a gravity fed vacuum fuel tap? That may also be leaking. if it is it will flood that cylinder & foul the plug every so often. Just something to consider. If it does the taps can be tweaked to seal again.

It is Dave. Tank has probably 15lt of fuel in it. It spent 24hrs sitting on top of a cardboard box while I had the bowl off etc. No gas leaked out, so tap is all good. Thanks for pointer tho

[F5 Dave]

Sweet they can tend to -no drama then:scooter:

[Shaun]

So it's a faulty design,not enough ''crush'' on the seal.Is this an OE seal? We have been having trouble these last few years with locally made rocker cover gaskets,they harden and shrink very quickly,leaking about 2 months after fitting,so now it's only OE for me.You may have to ''help'' the seal sit a little higher for the correct crush.But it's not designed to seal holding a liquid - the float level must be too high.

Hylomar is an ancient product,rumoured to come from the caldron of Getafix the Druid himself.It was the recomended sealant for Rolls Royce engines,and is excellent for alloy/alloy joints. 35 yrs ago it was a secret known to few...I used to get it from my friend who worked for Fodens,they used RR engines.

Now you can get it from Repco.


You sir are full of very usefull information- some one buy that man a beer:rockon:

[FROSTY]

Try the silly thing first mate---swap the float bowl and seal from number 4 over to number 1--the only negative is bleeding the carbs is a pain--the bleed screws will be the wrong side.
ER hang on theres a point--you sure it isnt the bleed screw leaking?

[MSTRS]

Not the drain screw. Had that problem a couple of years ago - was a crack in the bowl caused by someone (not me) overtightening the screw. Replaced the bowl and have had minor leakage around the interface ever since. Was getting worse so had to do something about it. So far, still dry as....