Sudden loss of power on freeway

[IIGVCII]

my 1983 GS1100GL while on the freeway will suddenly lose power and the rpm will drop and giving it more throttle only makes the engine louder as the rpms continue to drop. Sometimes it starts working again, other times i have to pull over and the bike just dies. The funny thing is i can just hit the starter and it comes back to life just fine and i can continue on my way. I can't figure out what is causing this problem, its almost like i'm running out of gas but i don't see how thats possible. Its not overheating because it happens even when the bike hasn't been running that long. It only happens at freeway speeds and it is very random. I've had it happen on a ten minute trip and about 3 times on a 350 mile trip i took. On the 350 miles back it didn't happen once. Again it is very random, doesn't matter if i'm going up or down hill but it never happens on the street (under 50mph) just on the freeway (maybe around 70mph). I hope somebody has the answer to this because its got me confused. :?

[SqDancerLynn1]

Sounds like a fuel problem, do you have a filter on it ?? If so remove it you don't need it, it will restrick fuel flow. Check the vent hoses, check the gas cap vent

[rgierer]

I had a similar expereince a few years ago. I had a slowly failing petcock. Upon rebuild or replace...don't recall which the problem was eliminated.

[jimcor]

I had a similar problem. Petcock was the culprit. Rebuild kit should be available for your model.

[tony23]

Hm - sounds like that may be part of my problem. By "petcock", do you mean the fuel supply valve (that you change from ON / PRI / Reserve)?

Would that also cause difficulty starting?

[Billy_Oliver880]

Hm - sounds like that may be part of my problem. By "petcock", do you mean the fuel supply valve (that you change from ON / PRI / Reserve)?

Would that also cause difficulty starting?

You are correct about the on/pri/res that is the petcock. Some say that its better to just buy a replacement petcock by pingle.

[JayH]

When you pull the petcock out of the gas tank check the screen on top of the petcock. If the tank is starting to rust you will see rusty flakes caught in the screen If you have enough of these flakes it can hamper the free flow of gas through the petcock and cause fuel starvation problems that you are experiencing.

[IIGVCII]

i have pulled the petcock off before and the screen looked fine, couldn't see anything wrong with it other than its pretty hard to turn, i guess i should rebuild it. thank you everyone

[pntrdave]

If the problem occurs everytime heres something you could try. Just switch it over to prime, if that fixes the problem then you'll know it is the pet cock.
Just make sure to turn the petcock back to run when you park the bike.

[Sandy]

Also do a quick check on the vacuum hose that goes from the petcock to the carb to make sure it's not kinked, cracked or collapsed. If it's bad it will only allow partial fuel flow. While you're at it check for a kink in the fuel hose also. If the fuel filter is fine and these check fine then it's probably petcock rebuild time.