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On my 1984 kawasaki gpz 550, my carbs have been leaking. When I first had this problem, it was only the middle two carbs. I ended up finding gas in my oil and air box. So I did an oil change and let air box vent. Now I took the carbs off, used fine sand paper on the little metal rod that the floats rotate around and made sure they weren't stuck when I put carbs back on. I took it for a ~10 minute ride and everything was great and my carbs weren't leaking gas like before. I parked my bike and in the morning, there was a small puddle of gas under my bike. It wasn't as bad as when it was previously leaking. So I went and asked a motorcycle mechanic and he said to make sure there isn't a spec of dirt in the seat and needle(which are like a couple month old). I took carbs apart and took seat and needle out and I couldn't see anything that would impede a good seal on the seat and needle.

I can't tell where the gas is leaking out from. I thought it could be a petcock issue since it is a vacuum petcock. I took it apart and cleaned it out and I thought that would have fixed it(probably what caused the gas in my oil though). It is a giant pain keep on taking the carbs off the bike only to see that it leaks.
 

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Did you check the float needles for wear around the tip? If you see any sort of circular mark they should be replaced - probably not that much $$..



Can you disconnect the petcock from the carbs without it leaking fuel all over? If it leaks you will most likely have to get a rebuild kit for it.
 

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Did you check the float needles for wear around the tip? If you see any sort of circular mark they should be replaced - probably not that much $$..



Can you disconnect the petcock from the carbs without it leaking fuel all over? If it leaks you will most likely have to get a rebuild kit for it.
As said, I replaced them a couple of months ago and bearly rode before started leaking gas

Before I cleaned out the petcock, it wouldn't stop leaking gas through the petcock on the 'on' and 'reserve' position. Now it doesn't leak but doesn't always close. I guess I will have to work on the petcock again. My petcock also doesn't have feed tubes that stick up to into the gas tank(the oem diagram shows them) and instead I have an inline fuel filter so maybe more gunk is preventing a good close seal when there is no vacuum
 

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Your float needles should stop the flow of fuel, even if your petcock does not. They are there to keep the fuel level in the carbs a constant, and, if they leak, they aren't doing that, and the engine is gulping gas. The petcock should be the second line of defense, and does have an OFF position, doesn't it?

If the floats are sticking, it could just be dirt that got by the filter blocking the valves, like little bits of decaying fuel line. Or, the levels could just be set too high; you can measure this with a thin bit of clear tubing on the drain, turned up alongside the carb. Open the drain, and the fuel will rise to the level inside the carb, and should be some distance below the bowl seat. You'll need the manual to know just what that should be, but my Intruder rear carb is 7mm, for example.
 

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Ah, I see it now. Gotcha.

Could be that the petcock rubber is going bad and sending debris down to the carbs. Do you have an inline filter?
 

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Ah, I see it now. Gotcha.

Could be that the petcock rubber is going bad and sending debris down to the carbs. Do you have an inline filter?
When I opened up the petcock, all the rubber gaskets were fine and made a nice seal when no suction was applied. And said in my second post I have an inline filter. I already have new fuel lines as well, tank has surface rust on it but fuel comes out clear and no debris in tank.

WintrSol said:
Your float needles should stop the flow of fuel, even if your petcock does not. They are there to keep the fuel level in the carbs a constant, and, if they leak, they aren't doing that, and the engine is gulping gas. The petcock should be the second line of defense, and does have an OFF position, doesn't it?

If the floats are sticking, it could just be dirt that got by the filter blocking the valves, like little bits of decaying fuel line. Or, the levels could just be set too high; you can measure this with a thin bit of clear tubing on the drain, turned up alongside the carb. Open the drain, and the fuel will rise to the level inside the carb, and should be some distance below the bowl seat. You'll need the manual to know just what that should be, but my Intruder rear carb is 7mm, for example.
It is a vacuum operated petcock so it does not have an off position, however, converting it to a manual petcock would be very easy if necessary. I have the carbs open now and when I checked two of the seat and needles, there wasn't a spec of dirt and the seat has a filter on it as well and there wasn't any dirt on the filter themselves. I am also 100% sure the floats are not sticking because if they were, then the carbs would leak gas when I took it for a ride but it only leaked after letting it sit overnight.

For setting the float level, the manual says this "With the carburetor level to the ground. check the fuel level in the tube. It should be slightly below the bottom edge of the carburetor body" So I reassembled the carbs and rigged it up to be level and have fuel going into it. The level is pretty different on all of them(I mixed up all the floats at one time). The manual doesn't specify the distance between the fuel level and the float bowl. If it is too high, would the carbs leak or is it if the level is low does it leak?
 

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On the carbs. there is a little screw that opens the drain in the bowl. make sure they are completely clean and tight when closed.

Also look for pin holes in the tank and gas lines.

If the gas was in the oil. you might have a head gasket leak, or worse a busted head.

your floats must push the pin althe way in to close the gas flow when the bowl has gas in it. That means adjust the floats to close the pin, not just to closing. The worst you can do is lean it out to much...and yes. carbs are a pain, so study hard and do it right once.
 

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The petcock in the on position shouldn't allow any fuel past it with the engine off. If that is happening, it needs to be fixed.

If fuel is getting past the float shutoff valve, it is either mis-adjusted, sticking, or has a bad seal.
 

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I would start with fixing your petcock first had a problem similar with a vacuum operated petcock where it never shut off and the flow of gas would overflow one of my carbs.
A rebuild kit is cheap you need one that replaces the rubber O ring on the plunger part as that part goes brittle and won't seal correctly.Also check your spring I very carefully stretched mine a little so it gave a little more pressure to close the plunger.
 

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It is a vacuum operated petcock so it does not have an off position, however, converting it to a manual petcock would be very easy if necessary.
Some do, some don't have an OFF position.
I am also 100% sure the floats are not sticking because if they were, then the carbs would leak gas when I took it for a ride but it only leaked after letting it sit overnight.
If the floats were sealing properly, they wouldn't leak while riding OR sitting over night. It doesn't take much grit stuck to a float valve to leak just enough to overfill a carb through the night, while the draw of the engine keeps it from overflowing.

For setting the float level, the manual says this "With the carburetor level to the ground. check the fuel level in the tube. It should be slightly below the bottom edge of the carburetor body" So I reassembled the carbs and rigged it up to be level and have fuel going into it. The level is pretty different on all of them(I mixed up all the floats at one time). The manual doesn't specify the distance between the fuel level and the float bowl. If it is too high, would the carbs leak or is it if the level is low does it leak?
Is that a factory manual, or a Clymer's? They should all be set to the same level, or your cylinders are running with different mixtures, which is never good. If that is not a factory manual, I would set them all to 7mm below the body/bowl seat, unless you find a better manual with the actual setting. If the level is too high, it doesn't take much to make it leak from the bowl seals, or to rise above the overflow tube, especially when the bike is on the side stand. Get them all set, and see what happens.
 

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Discussion Starter #11
Ok, so I sort of feel pretty stupid for this, but the needles were put in upside down. When I bought the bike, the carbs were already off and there was no needle or seat as the previous owner threw them out because they were bad so I didn't know what direction to put the needles in. I also found that the float needs to be 27mm from the carb bodies. I checked and they seemed fine. The carbs are back on the bike now and did run it for a couple minutes using a turkey baister to feed the gas. No leaking or anything.

My petcock seals are in very good condition but it will still leak a little gas. It is a drip leak but it seems like converting it to a manual petcock by pushing in the plunger part into the tube and using 'prime' will be my only option for now.
 

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As they say, you should learn something new ...

We've all discovered that we've made, in hindsight, an obvious or 'stupid' mistake. Wisdom comes from experience, and experience comes from mistakes (if we survive them).:D
 

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As they say, you should learn something new ...

We've all discovered that we've made, in hindsight, an obvious or 'stupid' mistake. Wisdom comes from experience, and experience comes from mistakes (if we survive them).:D
Cant disagree with that, at least I put the carbs right side up into the bike :icon_cool:

I converted my petcock to a manual petcock and is no longer leaking. With everything back together, I am not seeing a single drip of gasoline from the carbs either after everything hooked up for this long.
 
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