Quitting at high speeds

[amontyg]

My 82 gs550l has a habit of quitting when on the highway. This morning i changed out the black fuel hose from the tank to the carbs with a peice of clear tubing and ran the bike on the highway till it died. the fuel hose was empty so i am sure it is just starving for fuel. after a few minutes of priming the carbs it starts right back up. I rebuilt the petcock recently, but it had this problem with the original as well. Also i took a wrench and bled the one of the carbs a little to see if there was any fuel in them which there was. The problem only shows up when i run the bike at high speeds 70mph+ and i can usually predict it to happen when i stress the motor like when going up a hill. Could the floats be the most likely culprit or would the petcock still be a possiblility?

[Dogma]

Opinion around here is that petcock rebuilds are not usually effective at solving this problem. When I had this issue, I took mine apart but couldn't find anything wrong with the diaphragm, etc. Replacing it with a new unit solved the problem. My theory is that the control valve degrades, but the rebuild kits don't fix that.

Floats can't cause an empty fuel line.

[tone]

I agree with dogma a new tap is always a good idea with these problems

another thing to check is that the vent in the fuel cap is clear eg no air in = no fuel out :-) you could try running it for a while with the fuel cap open but taped down to eliminate this possable problem

[mf70]

Air leak between air box and carb? I'd been having lean/hot running problems for years; when I replaced the hardened rubber air horns between the air box and carbs she started purring like a kitten.

[doctorgonzo]

Kinks or "uphills" in the fuel line (or the wrong type fuel filter) can starve at high speed also.

[SqDancerLynn1]

Kinks or "uphills" in the fuel line (or the wrong type fuel filter) can starve at high speed also.

Agree !! Don't make the fuel line any longer than necessary.. also check the gas cap vent

[Jethro]

Make sure it's a 5/16" ID line, a 1/4" is very common, fits the tap and can cause fuel starvation. I also had this problem when I was running an inline filter, although it was on a thirstier bike than a 550. Still wouldn't cause the fuel line to be empty...

[t3rmin]

Also make sure your bowl vent tubes are routed away from wind.

[msauro]

I can't drive 65

Hi all,

New to here and GS bikes. I also am having a similar problem with my 550L. I just had the carbs rebuilt but it won't hit 65 mph and through the gears no RPM past 5.5k. It also stumbles when the air filter is installed. It has pep and not bad on town streets. I love the bike but I need to ride highways but can't.

It also started making a rubbing sound from inside but not related to RPM as I hear is at idle when holding the clutch. It sounds like something in a rolling assy.

HELP to a new guy from the masters?

[Clone]

Tank is not venting properly, or there is crud in the tank that is clogging the screen in the tank, then when you stop it falls off, fuel flows again and the cycle repeats problem is probably in the tank, not the carbs.

[amontyg]

hey guys so i was just thinking about this petcock problem a little more. is there any danger with altering the petcock so that the diapham doesn't work and fuel simply flows freely all the time?