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kerryg
9th September 2004, 11:09
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
9th September 2004, 11:11
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. :yes:

jrandom
9th September 2004, 11:15
Chewing gum?

riffer
9th September 2004, 11:17
Chewing gum?
need to work on your trolling there buddy...

vifferman
9th September 2004, 11:35
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...:buggerd:
He wasn't hurt, but got a fairly hard time when he confessed to his stupidity.:wacko:

kerryg
9th September 2004, 13:58
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
9th September 2004, 14:39
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
9th September 2004, 14:44
I'm not kidding...

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

kerryg
9th September 2004, 15:19
I'm not kidding...

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


MMMMMM.....nah :no:

kerryg
9th September 2004, 15:32
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... :rolleyes: .....but if I bugger it up I'll be shopping for a 40mm Mikuni carburettor :Oops:

jrandom
9th September 2004, 15:34
if I bugger it up I'll be shopping for a 40mm Mikuni carburettor :Oops:

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

riffer
9th September 2004, 15:45
Sounds simple... :rolleyes: .....but if I bugger it up I'll be shopping for a 40mm Mikuni carburettor :Oops:
Here you go Kerry - found one (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2488914378&category=35574&sspagename=WDVW)

vifferman
9th September 2004, 15:48
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... :rolleyes: .....but if I bugger it up I'll be shopping for a 40mm Mikuni carburettor :Oops: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
9th September 2004, 16:11
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
9th September 2004, 16:15
Here you go Kerry - found one (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2488914378&category=35574&sspagename=WDVW)


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

F5 Dave
9th September 2004, 16:16
Capillary action? Good luck buddy. I wouldn’t even trust the ‘wick in' stuff for something to seal petrol. If that is Loctite master gasket or the equivalent then that should work just fine applied as you say. A friend in the petrol chemical industry suggested I use it on the gasket (which I couldn’t replace quickly) for the bottom of the tank where the fuel pump goes in. Has been fine for years, but I’d give it a day or so just to give it the best chance to seal.

Motu
9th September 2004, 16:26
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.

A couple of weeks ago I had a leak in my Acerbis tank in the middle of nowhere,found that someone had drilled their first mounting hole wrong and fuel was pissing out of a 2mm drilling that the filler fell out of.I broke off a turkey feather in the hole and jammed a bit of roadside plastic under the washer to seal it.Got home on the rest of the tank.I drop kicked the turkey into the nearest ditch.I love the ''adventure'' in adventure riding.

vifferman
9th September 2004, 16:38
I drop kicked the turkey into the nearest ditch.I love the ''adventure'' in adventure riding.:killingme :killingme :killingme
Last bush ride I did (about 28 years ago), I was blithely riding along with my spare gas can in my pack..... pissing out petrol from the rust holes.:doh:
Had to top up the tank sooner than I expected.
That wasn't the end of it. I was happily crossing a river about eighteen inches deep, thinking, "No worries; she'll be as watertight as a fish's arse!" or whatever. Later at home, when I was cleaning the bike, I noticed a not insignificant crack in the magnesium cover over the points, from an earlier encounter with the rocks that masqueraded as the gravel on the logging roads. :Oops:

FROSTY
11th September 2004, 16:03
Seeing as you have the tube out Id run a smear of loctite around the 2 tube ends and press them back into place. To be sure the loctite doesn't run somewhere it shouldnt I'd make sure the pipe ends face upwards