Gas dripping constantly

81 XJ 550 seca

I just reconnected my tank, and put gas in it and after getting it started and running for a minute or two I realized it was dripping out through a tube connected to nothing pointing downward rear of the engine and way below the tank.

So what the hell is this tube and why is my gas coming out of it?

 

yes I have almost the same problem except mine is leaking somewhere around my carb. I think it might be the float tee. In your case if you look under your gas tank you can see a place where a hose connects for your vacumn, maybe that came undone. thers also two tubes that connect your petcock. Make sure you hooked them up on both ends and correctly. Hope this helps 8O

 

I installed the tank correctly. My previous description wasn't so good, and since a picture is worth 1000 words, here are 2 (click both for big):

The dark area under the air filter is where we're zooming in to...


This picture shows the tube, (with another one behind it). This is the dark area from the previous picture.


My friend says this is the gas overflow tube. Which means that since there is no off on the fuel petcock, there is a bad vacuum seal somewhere?

How do I fix this?

 

I'm an idiot and this thread should NOT have been posted. I searched gas leak and found a hundred threads exactly like this one.

Basically, my gas tank petcock is shot and should be replaced AND my carbs need cleaned since the float needles are stuck.

Yes?

 

You learn fast grasshopper.

You may be able to service the petcock. There is a sealing disc in them that can wear out. The guys at my local parts dept. assure me that is the usual problem. They were right in the case of mine. Is #14 in the picture. If there aren't ridges around the holes it's worn out.

 

Hey, I'm not trying to steal your thread but it sounds like you figured out your problem. I have a real bad leak also, but for me gas is squirting out right behind the gas reserve switch (a little bit higher up then your first picture shows). Does anyone have any ideas what my problem could be?

 

Bostik -- remember to change your oil too -- pretty likely you've got fuel in there now.

Snowridr - sounds like the seals on your petcock are going - where exactly is the leak coming from?

 

Yes, definitely. For one, it was a whole lot of gas that leaked out, and for two, the oil light comes on when I put the key in. :roll: But since I just picked it up, I was planning on doing that anyway. Luckily this happened first and not after the change!

And to make it worse, today it's snowing. At least I can pull the tank and take it inside before I freeze my hands off and try to work something out with the petcock.

Thanks for the tip about part 14 MiCarl, I'll definitely look into that first. But if there's too much other stuff wrong with it (gaskets? o-rings?), I might just put a valve in the fuel line as a temporary fix, since I can't afford a $50 replacement or a $30 rebuild kit.

 

Snowridr: Maybe the vacuum diaphragm on the inside part of the petcock. The plastic piece that goes between the two membranes has a little hole -- something about overflow, if I remember what I read correctly.

Bostik: good point on the inline valve being a *temporary* fix, because the petcock CAN be serviced, despite RickCoMatic's rhetoric to the contrary. ("OMFG U CANT FIX TEH 25YO PETCOCK THEY ARE TEH SUXXORZ!!!ONE!!!ELEVENTY!!!!!")

The "distribution valve" (that little five-hole thing behind the selector lever) is part of it; the vacuum diaphragm is another; the only two other things are the o-ring on the selector lever and the lever itself. If the back of it isn't perfectly flat, it can allow gas to leak. Some 600-grit sandpaper, given a healthy shot of WD40, and *lightly* sand the back of the selector lever until it's flat. That might help.

 

O-ring? More like o-no-ring! (part 18 on above diagram, if anyone cares)



There is an inch or so of snow on the roads right now, so I'll just pick up a replacement later, I'm sure an o-ring won't be hard to find.

Anyway, all the other parts look legit. I put a drop of oil and spread it over the gaskets that weren't busted after I opened them, since they dried like immediately after the gas evaporated (so I figured they shouldn't be exposed to air for the first time in like forever).

Check out the free plug for the stripped-screw-extractor people, second time I've used it on this motorcycle.

 

That petcock-to-tank gasket is incorrect.......

 

No screen on the fuel inlet visible - Just not in picture?

Make sure you pull (14) out and look at the other side. IIRC it's the back that wears.

 

Yea, I could kinda tell... it was made out of thin cardboard or something. I have no idea. But it didn't leak? :?

Also, there is an old rubber seal going around the whole thing that I didn't remove... that modified thingy is in addition to that. Hmm... what to do, what to do...

It was fine (as in... not smooth) on both sides, I didn't post the picture because it didn't focus correctly. You're right about the screen; I have an in-line filter, so I don't need to worry, do I?

Damn I hate getting bad news, so I'll just add that I installed a new o-ring! Hooray!


Edit: My guess is that one of the more recent owners re-did the petcock (hence one of the screws being stripped and all the parts looking fairly new), but installed a too-small o-ring that snapped after not much usage.

 

put a inline filter on it even if the petcock screens are good

 

Yea but can an inline filter keep me from not needing the screen on the petcock?

 

It can, but when it comes to the amount of grief that can be saved, the more screenage the better..........

 

if all you have is a inline only expect it to plug up quick, the petcock screen is much bigger and the chunks can slosh away

 

If you remove the screen from the petcock you will lose your reserve capability.

 

Nah - he still has the tower on there. Screen is gone off the tower.

 

Point taken. So it's just a screen that covers the whole tower? Screw it, I'm sure I can find something suitable.

What about that gasket that chacal pointed out is the wrong thing? I have no idea what the actual one looks like, besides... probably... rubber?

 

Well, the screen "covers" the whole filter tower (actually, the screen seems to be fitted from INSIDE the tower) but, I'm not sure that the screen has anything to do with reserve capability, unless the missing screen on the reserve side of the filter allowed a big chunk of something to get into the petcock reserve inlet port and clog it.....a possibility, but not all that likely.

Bostik, I would just replace the in-tank filter:

fl4) OEM Yamaha petcock Tank Fuel Filter. This is the tall, white filter unit (yours may have turned brown after all these years) that fits onto the petcock and goes up into the tank. 94mm (about 3-3/4") tall, which may differ slightly from the stock filter height, but it doesn't interfere with anything and doesn't change the performance. It's a swell idea to replace this filter whenever you have the petcock out! FITS ALL ORIGINAL XJ550/650 except Turbo models/750/700/900/1100 models. NOTE: some original petcocks used a shorter 2" tall filter, which is no longer available, and this taller filter will work just fine in place of it.

HCP116 OEM petcock in-tank Fuel Filter.
$ 14.00


Add an inline filter if so desired:

fl5) Aftermarket In-Line Fuel Filters. This is the cheapest and best investment you can make for a long, clean life for your carbs. Available as either round or cone-shaped clear plastic filter units, they go a long way towards preventing contaminants from your fuel tank ever getting into your carbs.

HCP763 aftermarket In-Line Fuel Filter, round, 1/3" diameter filter has a clear, see-through 1-3/4" long housing with a metal screen filter. This is a straight-thru design, with inlet and outlet tubes 180-degrees opposite each other. For 1/4" fuel lines.
$ 3.00

HCP2733 aftermarket In-Line Fuel Filter, cone-shaped 2" long filter has a clear, see-through housing with a bronze mesh filter. This is a straight-thru design, with inlet and outlet tubes 180-degrees opposite each other. NOTE: the sintered bronze filter element goes TOWARDS the tank.
$ 3.00

HCP3591 aftermarket In-Line Fuel Filter, cone-shaped 3" long filter has a clear, see-through housing with a bronze mesh filter. This is a straight-thru design, with inlet and outlet tubes 180-degrees opposite each other. Longer length results in a higher fuel flow and filtering capacity. NOTE: the sintered bronze filter element goes TOWARDS the tank.
$ 3.50

HCP2734 aftermarket In-Line Fuel Filter, cone-shaped 2" long housing has a clear, see-through housing with a bronze mesh filter. This unit has 90-degree angled inlet and outlet tubes (pointed 90-degrees opposite of each other), which is useful in the "tight-squeeze" conditions that exist under some models! NOTE: the sintered bronze filter element goes TOWARDS the tank....meaning the 90-degree rotated (from the centerline) INPUT nipple (from the tank) is approximately 1" off the centerline of the housing. The entire housing---including the inlet nipple, is about 2" wide, and---including the outlet nipple---is about 2-1/4" long.
$ 3.50


and replace the oval rubber petcock-to-tank o-ring:

fp10) Petcock fuel position Petcock-to-Tank O-Ring. These are usually worn out and need to be replaced whenever you remove the petcock. This rubber o-ring fits onto the top of the petcock.

HCP117 OEM Petcock-to-Tank O-Ring. Fits all XJ550/650 (except Turbo models)/750/1100 models. Molded into a oval shape as original.
$ 3.50


Lots more petcock rebuild parts, complete petcocks, replacement petcocks, petcock rebuild services, already-rebuilt-petcocks, fuela nd vacuum lines, etc. at:

http://www.xjbikes.com/Forums/viewtopic ... t=195.html