Carb or petcock problem

[Guest]

My guess is there is gunk holding the float needle open on that #3 carb. Is the tank clean?

That would be my guess also, something is going on very funny with that carb, it could be several things, a bad float seat or needle, or even a float with a small hole in it keeping it from floating, or it's just hanging up, keeping open that float needle valve letting fuel flow, but then again your petcock should quit allowing fuel to flow with the engine off with your petcock not in prime. I believe also sometimes the floats stick when on the sidestand as your bike isn't completely upright and it puts some side pressure on the float, I have found on more than one occaision with my GS1000 and GS1100 some gas overflowed when left on the sidestand
and I accidently left the petcock in prime. And that is clearly mentioned in
each owners manual about not leaving the bike in "Pri."
I think I would check the operation of the petcock first, to make sure it doesn't leak in the "on" or "reserve" position with no vacuum applied.

 

[dluszcz]

Here is the latest attempt to fix the leak.

BTW, the tank is clean. I had the Kreme baked out of it and a new liner applied professionally at a radiator place that lines all kinds of gas tanks with this stuff. Even if I dent the tank, the liner is flexible enough to not crack and leak. So, I'm ruling out that the tank is dirty and some of the specs could be lodging in the float needle.

However, just to be certain here's what I did.

Took the carbs off, again. I'm getting pretty good at that!

I pulled the bowls off of carbs #3 and #4.

I dug through my box of leftovers and found my last 3 float needles. Only 1 had no ring around the top due to wear, so that is the one I used.

I also grabbed another seat for the float needle. I sprayed both with carb cleaner and then used compressed air to blow out everything.

I took the seat and float needle from carb #4 and put it into carb #3.

I took the extra float needle and seat and put it into carb #4.

Reassembled everything and took her for a short ride. She was running for about 10 minutes and on the road for about 3 miles. Now she's back in the garage on the side stand with a new piece of cardboard underneath.

I'm waiting an hour before I go back out there to look and hopefully, no wet spot. ray:

Otherwise, I'm STILL in the same place and for the life of me, can't figure out what is wrong.

Edit: Also, the petcock is not on PRI. I moved it a touch to the ON position but the knob is not completely up and down. I moved it a touch to the RES just in case the petcock wasn't closing all the way at the bottom point.

 

[dluszcz]

Update,

Still leaking gas from carb #3. Garage smells like gas and the wet spot is about the size of a tennis ball.

Problem still not solved and this is a different seat and float needle.

I'm still open to any other ideas. Kind of getting frustrated with this particular problem.

Honestly, can it really be just a bad petcock? When I took the tank off and put it back on, same thing happened with the fuel line. There was some fuel that came out when I placed it down onto the 2X4s and cardboard, theoretically clearing any remaining gas out of the line.

So, my thinking is that it should have all leaked out at that time. When I went to put the gas tank back on and picked it up from the 2X4s, it had more gas come out of the fuel line, leading me to believe that the petcock is bad.

 

[Guest]

Update,

Still leaking gas from carb #3. Garage smells like gas and the wet spot is about the size of a tennis ball.

Problem still not solved and this is a different seat and float needle.

I'm still open to any other ideas. Kind of getting frustrated with this particular problem.

Honestly, can it really be just a bad petcock? When I took the tank off and put it back on, same thing happened with the fuel line. There was some fuel that came out when I placed it down onto the 2X4s and cardboard, theoretically clearing any remaining gas out of the line.

So, my thinking is that it should have all leaked out at that time. When I went to put the gas tank back on and picked it up from the 2X4s, it had more gas come out of the fuel line, leading me to believe that the petcock is bad.

It does sound like a bad petcock. You wouldn't be getting any fuel out of carb #3 if your petcock wasn't leaking as all fuel goes through it to your carbs. I think your petcock is leaking internally. What you can do
is check your petcock for serviceability.
Disconnect your fuel line at the petcock and put another fuel line on that you can run to a gas can or something (I use Arizona Ice tea Jugs because they're clear), disconnect your vacuum line at the petcock and run another line to it. Make sure your tank has more than a "reserve's" amount of gas in it.
On "Pri" the gas should run freely. When switched to "On" your gas should cut off "Completely" unless you apply vacuum (suck the vacuum line), the same for "Reserve." What I've found rebuilding petcocks is sometimes they
leak, won't completely shut off when in the "On" position. A steady drip will fill up a gallon in a couple of days or less. Remember, in the "On" position it must cut off the gas completely, make sure you have more than a reserves amount of fuel in the tank when you test that. Empty that catch tank back into your fuel tank and place your empty catch tank back into position and leave it there for awhile (like a day) and see how much fuel is accumulating, no fuel is good.
If it does leak, make sure you have a catch tank big enough to at least hold the amount of fuel in your fuel tank.
Now test it and let us know the results!

 

[Matchless]

I did what you said to try to test the petcock.

I put the fuel line into a plastic container. Hooked up a tube to the vac inlet.

Put the petcock on PRI and gas came out. Put it back to ON, gas stopped.

Sucked on the vac tube, gas came out. Stopped sucking, gas stopped flowing.

Moved petcock to RES and same result sucking on the vac line.

I had the tank off the bike and moved it to the floor on top of a couple of 2X4s and some cardboard. About an hour later, I went to put the tank back onto the bike, and some gas drops came out of the fuel line. The petcock was still in the ON position.

I just got home from work and checked the bike again. There is a wet spot on the cardboard, but not nearly as big as yesterday. The fuel lines are dry. The filter is dry. The top of the engine is dry. However, that doesn't mean it didn't leak yesterday and dry up from sitting overnight. But, I don't see any signs that the filter or fuel lines leaked.

Back to the same spot, carb #3 leaking. Carbs #1 and #3 are still rich, #2 and #4 are still lean.

You seem to only have a small leak now, as it only makes a small spot after riding and your new OEM petcock seems to test OK. It could just be the fuel in the fuel line that empties itself past a faulty float needle valve every time you put the bike off.
Put your bike on prime and feel around under the carbs for any leaks or better still check them off the bike with a dummy tank.

Edit: To set your mind at ease go for a ride and when you get back carefully put a longer bit of fuel line from the petcock into a container. Try not to jar or disturb the petcock at all. If it is faulty it must leak fuel. The leak is not coming out of any overflow pipe is it, tank fuel level sender or any other? Maybe try to localise it more definitely other than a spot on the floor if possible?

 

[dluszcz]

I will do what sedelen said and take the tank off the bike to test the petcock.

This morning, I went to check the size of the spot and it is now the size of a cantaloupe. Judging by that size, I think I'm going in the wrong direction!

So, we'll do this latest petcock test after work and in a couple of days, I will report the results. I hope that is what it is, just to solve the problem!

Thanks to all for your input.

 

[Guest]

Last fall, I had the tank baked to get the Kreme out of it. Then, I took it to a radiator place in Woodstock, IL that lines gas tanks with a guarantee. I've had zero problems with that any kind of debris in the fuel.

In addition, I have a clear gas line and I have a fuel filter installed just before entering the carbs.

I'm assuming that you had you tank re-sealed, if that is so you might want to check the very little vent hole on the inside of your gas tank filler neck (believe it be in the 3 o'clock position when you look forward, or to your right side) to make sure it isn't plugged with sealer. Your tank has to breathe. This is a long shot but since were grasping at straws, I was thinking it could possibly be a restrictive vent in that filler neck, or even the vent to your gas cap.
If so, as the fuel in your tank cools, vacuum could build up enough to activate your petcock when in "On" or "Pri." I don't think it would take all that much vacuum to do that either.
Also, those in-line filters often do more harm than good, I would be inclined to get rid of it if your petcock has a good filter screen.

 

[Guest]

I'm assuming that you had you tank re-sealed, if that is so you might want to check the very little vent hole on the inside of your gas tank filler neck (believe it be in the 3 o'clock position when you look forward, or to your right side) to make sure it isn't plugged with sealer. Your tank has to breathe. This is a long shot but since were grasping at straws, I was thinking it could possibly be a restrictive vent in that filler neck, or even the vent to your gas cap.
If so, as the fuel in your tank cools, vacuum could build up enough to activate your petcock when in "On" or "Pri." I don't think it would take all that much vacuum to do that either.
Also, those in-line filters often do more harm than good, I would be inclined to get rid of it if your petcock has a good filter screen.

After giving it further thought, I believe I'm absolutely wrong on that possibly being the problem because of vacuum building up in your tank, I just don't see how it could affect your vacuum line going from the petcock to the carbs, but even still you may want to check that filler cap vent hole to ensure it isn't clogged with sealer.

 

[dluszcz]

I had to pickup some exhaust header bolts and was talking with the parts counter guy and he asked me if I switch the floats themselves? I told him that I did not.

I thought it was the float height, needle, or seat. Taking his advice, I dug up another float in the box o' leftovers and cleaned it up. I pulled the carbs, AGAIN, and switched out the floats.

Just came in from a 5 mile ride and the bike was running for about 10 minutes again. I'm hoping, praying, ray:that this is what was causing the leak.

I held the old float under some water and didn't see any bubbles, but that doesn't mean that it didn't have a hole in it that I couldn't see.

I'll update in about an hour, hopefully, with good news!

 

[dluszcz]

Well, that wasn't the solution either. New wet spot on the cardboard. About the same size as usual.

1 idea left. I'm going to take the float, needle, and seat from carb #1 and put it into carb #3.

If carb #3 still leaks, I would have to reach the conclusion that the petcock is the culprit.

 

[dluszcz]

Just switched the float, float needle, and seat from carb #1 to carb #3 and the same from carb #3 to carb #1.

Because Mother Nature doesn't like Chicago for some reason, it just started to rain as I was warming up the bike to ride it. So, I let it run for about 3 minutes in the driveway before I shut it down and pulled it back into the garage.

I figure there's should be more than enough gas that passed through the carbs that if it still continues to leak, it's not going to matter how long it is on or how long I ride.

I just want this problem to be solved!

Edit: I decided to take the overflow tube off the carb #3 and put a blue shop paper towel underneath folded twice over to catch anything. If it's leaking, I should know in the next couple of minutes.

And, if this doesn't stop the leak, going to take the tank off, run a tube from the petcock to a gallon container, and let it sit overnight to see how much leaks out.

 

[dluszcz]

Tank is off. Longer hose attached to the fuel line and the vac tube attached to the vac line. I put a doubled up piece of cardboard with a small block to simulate the tank is on the side stand.

Lots (well, in my opinion anyway) of fuel came out of the line when I jostled the tank placing it on the work bench. The petcock was in the ON position. I did the same tests moving to PRI, back to ON, RES, back to ON with the same results as earlier.

So, I completely dried a small container (decided not to use the gallon container cuz it wouldn't sit well on the make shift table) and placed a piece of cardboard on the bottom (so that I know if anything leaked).

I feel confident that the leak is not the petcock and I'm hoping that 1+ gallons of gas all over the make shift table and garage floor are not the result of my over confidence.

The bowls of the carbs are still full and guess what? #3 still has a drip. For the life of me, I cannot figure out what the heck I have to do to get this to stop leaking.

I'm calling it a night as I'm so frustrated that I'm not thinking straight. I will think about this while working tomorrow and maybe there are more suggestions posted that I will be able to attempt to get carb #3 to stop leaking.

 

[Nessism]

Why not measure the fuel level? I've read here before where guys get a piece of clear tubing and sort of smash the end than screw it into the drain port threads and it's good enough to not leak. My guess is your floats are letting too much fuel in.

 

[7981GS]

After giving it further thought, I believe I'm absolutely wrong on that possibly being the problem because of vacuum building up in your tank, I just don't see how it could affect your vacuum line going from the petcock to the carbs, but even still you may want to check that filler cap vent hole to ensure it isn't clogged with sealer.

I agree. It could be the cause.
Just not being able to vent, builds a lot of pressure! (Warm fuel expands.)

Daniel

 

[Tom R]

What side of town are you on?

 

[dluszcz]

The petcock has been officially ruled out. Not a single drop on the cardboard that was placed inside the plastic container.

The vent line in the gas tank is clear. I am able to stick a safety pin all the way through with zero resistance.

The gas tank was removed almost immediately after I let it run in the driveway. This morning, there is a wet spot still on the cardboard. I'm betting the bowl should be close to empty by now.

It's been brought to my attention that maybe I accidentally switched the carb bodies to #2 and #3 while rebuilding them. I kept all the parts together but maybe I grabbed the wrong one or something.

I'm waiting for pics for what carb body #2 and #3 look like on another set of carbs via email to see if maybe that is what I did. I'd feel like such an idiot

if that is what I did! But, who knows. This is my 1st rebuild and I'm not ruling out any possibility.

I hope that is the solution, no matter how it makes me look. If that is it, I feel like I wasted everyone's time trying to help me and for that, I apologize. And, you can bet that I will take even better care to make sure I don't mix up the parts again like that.

To Tom R, I live in the northern suburbs, Johnsburg.

 

[dluszcz]

I don't think I switched carb bodies. If I did, the adjustment screws would be on the wrong side, right?

 

[Matchless]

I think you should have a closer look at the float bowl drain screws. most likely one of them is leaking. The bowl when full and not having the tank to feed it should not leak any fuel. It can overflow though but needs to have something feeding it.

 

[rustybronco]

I'm waiting for pics for what carb body #2 and #3 look like on another set of carbs via email to see if maybe that is what I did. I'd feel like such an idiot

Carb #3 has the BB plugging one of the two holes where the float is located. on carb #2 both holes are open.

 

[cowboyup3371]

I think you should have a closer look at the float bowl drain screws. most likely one of them is leaking. The bowl when full and not having the tank to feed it should not leak any fuel. It can overflow though but needs to have something feeding it.

I would second Matchless here. As simple as it is, these are perhaps the easiest screws to forget to tighten back up; I know, I did it.