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Okay so I finally got the carburetor to stop leaking for a couple of weeks now and the GPz has been running fine. Turned off the engine came back a couple of hours later it would not start. Put the choke on all the way and it fires and screams at high RPM for a bit then I turned the choke off and the engine sputters and dies.

Come back this morning and found the carburetor is leaking where the carb connects to the engine. This is only happening to carb 1 so I took out the K&N air filter to get a look see inside and found the float area to be full of gasoline then opened up the butterfly valve and saw a small puddle of gas sitting in the butterfly area. It didn't look like much so I drained the float bowl and wiped away the gas from the carb-engine area and I see a some wetness forming near the carb throat again and in an hour it becomes quite wet with gas.

Any ideas on what's going on? It's only affecting carburetor 1 and I didn't leave the PRIME on this time. If it's needle related is there any way I can reseat it without taking apart the whole carburetor assembly?

Thanks. The engine is a KZ750R... if anyone has experience with those or similar.

Sounds like the needle valve is hanging up, allowing the float bowl to overfill. Normally, there would be an overflow port with a hose running down to drain the excess gas, rather than allowing it to puddle in the intake area.

The seat for the needle valve may be damaged or you may have some tiny piece of crud hanging up the needle valve. Another possibility is a damaged or mis-adjusted float.

Check your oil to make sure gas hasn't leaked past the rings and contaminated it.

In addition to what was said, sounds like the petcock needs rebuilding if it is still flowing fuel while not in the prime position.

If you have room to just take the one bowl off then you might can fix it without removing all the carbs.

For sure either the petcock and/or the needles. And definitely check your oil for contamination.
I'd definitely check your needles. Check for a slight wear in them, if you can feel it with your fingernail they need to be either sanded down with emery cloth or replaced.

Thanks for the replies. Yeah it was working right before and the leaking stopped but then started up again out of nowhere. The last thing I did after riding was putting GumOut Carb cleaner additive into the tank. And when I tried starting it again after a couple of hours of leaving it off it cranked but wouldn't fire unless the choke was pulled all the way out. Every time it cranked some cracks of fuel would start forming on the throat leading to the engine of carb 1.

There's no oil contamination or at least not much gas going into the oil because my tank is still pretty full (another reason why I can't remove all the carbs, the drain screws aren't budging so it requires me to remove the bowl itself). Which leads me to another thing... I only got a backside view of the carburetor once the air filter on carb 1 was removed. I unscrewed the top of the carb and took out the cover and spring and diaphragm valve to get a look at the butterfly valve. Opened up the throttle to get a better look through and didn't see any gas dripping or flowing which made me even more curious.

Reason why I haven't separated the carbs from the engine is because after unscrewing the clips on the throat and what not it won't budge. Yeah, the manual is taking it's sweet time in getting to me so I'm gonna have to work "blind" but so far the assembly is pretty straight forward.

Lastly I checked the hoses and nothing out of ordinary and were in better condition than on my 2001 Vulcan. Thanks for any more info. I would have pics but my fear of gas and electrostatic discharge from the camera...

Ok, yesterday the carburetor stopped leaking on its own. Today it starts back up on its own... I haven't been able to pull the carbs off the engine connections to get a look at the needles. The manual still is on back order and since it's Thanksgiving it won't be here for a while.

Since it stops and starts again could it still be a float needle problem? I checked the vacuum hoses and all seems well. I tried to take off the float bowl on carb 1 and drain it from there but fuel started to flow in different directions. The drain screw is stuck and no matter what I put on it the thing won't budge. Any ideas on where to go from here? Did it have anything to do with the GumOut carb cleaner additive I put in? I really want to ride it again considering it loves leaving tire streaks after each take off.

Thanks and Happy Thanksgiving to those who celebrate it this week.

Yes, the problem is probably still the float needle. And the only way to fix it permanently is to get that carb off and either clean out the crud holding open or replace the bad needle valve seal. My money is on the bad seal/seat scenario.

Is your fuel petcock diaphragm in operation condition?

BuzZz wrote:Yes, the problem is probably still the float needle. And the only way to fix it permanently is to get that carb off and either clean out the crud holding open or replace the bad needle valve seal. My money is on the bad seal/seat scenario.

Is your fuel petcock diaphragm in operation condition?

Does it involve removing the gas? I ask because the fuel might leak faster if I remove the vacuum (mostly fear that's clouding my judgement.. so try not to laugh). Since I cannot drain the fuel tank using the drain screws as they won't budge I have to leave the fuel in there or find another way to drain it. I would disconnect the fuel line and drain it from there but I'm not so sure that it would be wise.

Once the gas is out then maybe I can do more thorough inspection without fear of spillage.

If the petcock is working as it should, removing the fuel lines will not cause gas to drain. As long as it is NOT in the 'prime' position.

Then you can yank the tank and get to the carbs.