A little petrol leak repair

[kerryg]

I have a small amount of petrol weeping from a tube on the outside of one of my carburettors. It's a very small diameter brass tube (around 2-3mm O/D), in an elongated u-shape something like this:


====l= (a)
ll
ll
ll
ll
ll
ll
ll
ll
====l= (b)

(a) and (b) are pushed into the body of the carb, in an interference fit. The reason for the leakage seems to be that the tube has been knocked and is not seated as tightly at (b) where the petrol weeps out. The tube is intact, just a bit bent, and I can have already got it pretty straight just " by eye" so I'm hoping it will not leak when re-fitted but it's a bastard of a thing to get at and I don't want to take any chances so I am WONDERING (this is the question...FINALLY) what else I might use to give me some additional pertrol-tightness. I thought of PTFE tape but I'm not sure if it will work (given that the tube is an interference fit, I guess it will be scraped off in the insertion process). Some kind of Loctite liquid product seems a possibility. Any suggestions?

[riffer]

I have the same problem with my reserve/main petcock.

When I dropped the bike it got wrenched off the bike and the line from the reserve, which appears to be an interference fit too, is loose, and gasses of a petrolly smell.

I'd be keen to find a solution too.

[jrandom]

Chewing gum?

[riffer]

Chewing gum?

need to work on your trolling there buddy...

[vifferman]

I'd try loctite (one of them), or else it'd have to be something epoxy-based, like Araldite, or that mouldable stick stuff (can't remember the name - "KneadIt"?).
Heh - reminds me. One of the guys on the US SupaHock forum dented his tank (flipped his bike practising wheelies). He found a product for dent removal that involved welding a peg onto the dent, then there was a thing that attached to that to pull the dent out. Being safety conscious, he spent a lot of time purging the tank with air. The tank still exploded, possibly because he left the cap on and/or because there were still remnants of gas in the seams...
He wasn't hurt, but got a fairly hard time when he confessed to his stupidity.

[kerryg]

I'd try loctite (one of them), or else it'd have to be something epoxy-based, like Araldite, or that mouldable stick stuff (can't remember the name - "KneadIt"?).

Thanks F/S I had a look at the Loctite (Henkel) website and it looks like they'll have something suitable so I'm off to the engineering supplies place tomorrow.

[F5 Dave]

The tube is brass yes? Solder around the end (use a bit of flux) before you push it back in should be fine. Failing this 24 hr araldite pushed in the hole before you insert it will work just fine too as long as you don’t go crazy & fill the hole. It is unlikely to work if you just smear it on the outside though.

My father helped me fix a petrol tank with araldite. The trick was to make sure some poked through so when it sealed it formed a mushroom so it couldn’t fall out. About 5 pin holes (opened them up a bit to push some through), never leaked again.

I did a similar thing on my RG50 when returning form the Cold Kiwi the tank started leaking. I only allowed the araldite to cure for 30min & it was hardly an ideal environment but it got me back to Wellington.

Anything you do involving weld or solder with a gas tank the tank should be full of water, even petrol with the lid on is safer than having the cap off & just fumes.

[Paul in NZ]

I'm not kidding...

Try a bit of soap.. Just remember to replace it after washing / rain.

[kerryg]

I'm not kidding...

Try a bit of soap.. Just remember to replace it after washing / rain.

MMMMMM.....nah

[kerryg]

The tube is brass yes? Solder around the end (use a bit of flux) before you push it back in should be fine. .

Yes that could be worth a try but first I'm going to try Loctite. I shot down to Auckland Engineering Supplies (great place to buy stainless replacement fasteners by the way...but I digress) and their suggestion was Loctite 542 in combination with ever-so-slightly opening out the hole in the carb body, and ever-so-slightly sanding down the brass tube, with very fine sandpaper, and so create a narrow space in which the Loctite can fit. Sounds simple... .....but if I bugger it up I'll be shopping for a 40mm Mikuni carburettor

[jrandom]

if I bugger it up I'll be shopping for a 40mm Mikuni carburettor

New carburetor shopping, eh. Life just sucks, sometimes, dunnit...

[riffer]

Sounds simple... .....but if I bugger it up I'll be shopping for a 40mm Mikuni carburettor

Here you go Kerry - found one

[vifferman]

Yes that could be worth a try but first I'm going to try Loctite. I shot down to Auckland Engineering Supplies (great place to buy stainless replacement fasteners by the way...but I digress) and their suggestion was Loctite 542 in combination with ever-so-slightly opening out the hole in the carb body, and ever-so-slightly sanding down the brass tube, with very fine sandpaper, and so create a narrow space in which the Loctite can fit. Sounds simple... .....but if I bugger it up I'll be shopping for a 40mm Mikuni carburettor

I don't see why you'd need to take it apart; surely being runny, the loctite will be drawn in by capillary action, particularly if you give the tube a wiggle as you apply it around where it meets the carb body?

[kerryg]

I don't see why you'd need to take it apart; surely being runny, the loctite will be drawn in by capillary action, particularly if you give the tube a wiggle as you apply it around where it meets the carb body?

The brass tube is a VERY tight fit. I honestly doubt there's enough of a gap for even a very runny liquid to get in and I've got the sucker out now anyway so ...

[kerryg]

Here you go Kerry - found one

Thanks Celtic but I'm hoping not to have to buy one if all goes well