Pingel installed - fuel blowing into airbox!

[dogeatshouse]

I just purchased a used 1980 GS750E. Got it running initially, but noticed fuel leak from petcock. Just finished installing Pingel replacement (after researching here), and now fuel foaming and overflowing out of airbox behind carbs! Any suggestions on where to start next? Dying to ride before it gets cold again this year.[-o<

[Joe Nardy]

I believe the Pingel petcock does not use vacuum to open the valve like the stock petcock. If you do not turn it off it is like the stock petcock being left in the 'prime' position. Eventually fuel will leak past the float seals and flood into the airbox. You may want to change your oil too since fuel may have gotten into the crankcase.

Thanks,
Joe

[2005JJT]

If you didn't have an issue with overflow before the petcock was installed it's in the wrong position and thats the problem. If it's not the petcock it's the float valves. Check that they are set to the right height. I hope it's the petcock.

[dogeatshouse]

I believe the Pingel petcock does not use vacuum to open the valve like the stock petcock. If you do not turn it off it is like the stock petcock being left in the 'prime' position. Eventually fuel will leak past the float seals and flood into the airbox. You may want to change your oil too since fuel may have gotten into the crankcase.

Thanks,
Joe

I think fuel did get into the crankcase oil and I'll have to change it. You're right the pingel doesn't have a vacuum, but I sealed the line going from the back of the original petcock to the front of carbs (other line is fuel because it had the inline filter on it). There is another long line going from the back of the carbs but I assume this is for venting? So after I change the oil, double check the vacuum line plug, and then what? Replace float seals? (dreading taking the carbs off already).

[Joe Nardy]

I think fuel did get into the crankcase oil and I'll have to change it. You're right the pingel doesn't have a vacuum, but I sealed the line going from the back of the original petcock to the front of carbs (other line is fuel because it had the inline filter on it). There is another long line going from the back of the carbs but I assume this is for venting? So after I change the oil, double check the vacuum line plug, and then what? Replace float seals? (dreading taking the carbs off already).

Just remember to turn the Pingel petcock off after every ride. Others on this site have had the identical problem. The stock petcock turns itself off when the engine isn't running. The vacuum line from the carbs opens the valve when vacuum is present. If you pull the fuel line off with the stock petcock and no vacuum applied no fuel will flow until vacuum is applied and opens the valve. With the Pingel fuel flows all the time. It will eventually get past the float seals.

Joe

[dogeatshouse]

If you didn't have an issue with overflow before the petcock was installed it's in the wrong position and thats the problem. If it's not the petcock it's the float valves. Check that they are set to the right height. I hope it's the petcock.

Not sure if there was overflow before, took it out for a spin around the block after charging the battery and noticed the fuel leak on the floor. Thought maybe it was just the petcock leaking all over everything else since I could see drip from there. Since I put on the pingel, no more drip from underneath carb bolts, so I thought I got lucky. Since pingel though, fuel started pouring out of the line from the airbox so I took off the rear airbox and fuel started foaming out after I got it started and gassed it.

(guy I bought it from, said it had just been serviced, cleaned and synched....)

[dogeatshouse]

Just remember to turn the Pingel petcock off after every ride. Others on this site have had the identical problem. The stock petcock turns itself off when the engine isn't running. The vacuum line from the carbs opens the valve when vacuum is present. If you pull the fuel line off with the stock petcock and no vacuum applied no fuel will flow until vacuum is applied and opens the valve. With the Pingel fuel flows all the time. It will eventually get past the float seals.

Joe

I turn the pingel off, read here about the carbs getting gunked up and even put a pinch off on the original petcock fuel line before I swapped it out. So after I change the oil, recharge the battery again (too much cranking), let the fuel drain out.... then I should try again tomorrow? If its gushing out again should I look into getting the carbs redone?

[dogeatshouse]

If you didn't have an issue with overflow before the petcock was installed it's in the wrong position and thats the problem. If it's not the petcock it's the float valves. Check that they are set to the right height. I hope it's the petcock.

Just curious how the pingel could be in the wrong position.... I cleaned all surfaces, coated everything with the gasket goop and buttoned it up. Wrapped the threads with enough teflon so the pingel insignia pointed out and checked for flow and leaks.... off on and reserve works....?

Starting to think I'm gonna have to learn carb rebuilding.

[Joe Nardy]

I turn the pingel off, read here about the carbs getting gunked up and even put a pinch off on the original petcock fuel line before I swapped it out. So after I change the oil, recharge the battery again (too much cranking), let the fuel drain out.... then I should try again tomorrow? If its gushing out again should I look into getting the carbs redone?

Let's back up a step. Maybe I misunderstood the problem.

Does the fuel fill the airbox when the bike is sitting with the petcock turned off? If so, the petcock is defective. The only way fuel can get to the carbs (or anywhere else) is through the Pingel petcock. Turn the petcock to the off position. Disconnect the fuel line from the petcock (put something under it to catch the fuel). if fuel flows from the petcock it is defective.

If the problem happens when the bike is running and the petcock is turned to the on position the problem is probably a stuck float. Sometimes you can do a quick and dirty fix by tapping on the carb bodies. Otherwise you'll have to disassemble the carbs and clean or replace the float needles and seats.

Joe

[Joe Nardy]

You can probably determine which carb has the defective float. Turn the petcock on and let the bike sit for a while. Then open the screw on the bottom of each carb and drain the fuel out. Carefully measure the amount from each carb. If one carb had a lot more fuel than the others it is the one with the stuck float.

Joe

[dogeatshouse]

You can probably determine which carb has the defective float. Turn the petcock on and let the bike sit for a while. Then open the screw on the bottom of each carb and drain the fuel out. Carefully measure the amount from each carb. If one carb had a lot more fuel than the others it is the one with the stuck float.

Joe

I'm thinking I have a float stuck.... got a theory that its the first carb... felt the headers after the last time it ran today... all very hot except first one which was warm but not hot like the others? Petcock seems to work absolutely fine, fuel when on reserve and on... no fuel when off. Best looking part on the bike! :-D

[KEITH KRAUSE]

Your problem is a stuck/dirty float valve or a sticking float at one or more carbs.
Also, be sure the vacuum port at carb #2 is capped and the other two float bowl vent lines are clear/not kinked and run up behind the airbox area.

[dogeatshouse]

Your problem is a stuck/dirty float valve or a sticking float at one or more carbs.
Also, be sure the vacuum port at carb #2 is capped and the other two float bowl vent lines are clear/not kinked and run up behind the airbox area.

Think I could get away with just using a couple cans of carb cleaner on them after taking them off? Or will they need a full disassembly - reassembly? I sent an email off to the person who had the o-rings but got no response from them

[KEITH KRAUSE]

Think I could get away with just using a couple cans of carb cleaner on them after taking them off? Or will they need a full disassembly - reassembly? I sent an email off to the person who had the o-rings but got no response from them

You can do a partial cleaning by removing just the bowls. Takes some fiddling to re-install the float valve and floats and pin though. If you have a stuck float pin it's better to have the carbs off to remove it. I've cleaned/cleared dirty float valves and seats like this before, but you may have more rust/dirt in the gas tank and passages leading to the float chambers and if so the tank and carbs should be completely cleaned/repaired or this will happen again. Whatever you do, don't let carb cleaner contact any rubber parts for long. Rinse off immediately with fuel.
If you don't find any rust/dirt on the valves or their seats, you could have one or more float needle valves wearing out. This would mean the valve tips may be grooving or the spring loaded float pins getting weak.