Carb problem or timing issues on 83 gs750es?!

[Anonymous]

Runs decent thru the gears, however up in the higher speeds, upper 4th and all thru 5th, she keeps backing off, even though the throttle is the same. Feels very jerky. it goes forward, then backs off, jumps forward, backs off... also, very frequently now, it acts as if she runs out of gas at speeds over 85. hit 100, let off a bit, and motor dies. Sometimes I can get her to get back running if I close the choke for a bit and let her come to a stop, she will start back up. Which lets me think too much fuel? Flooding the engine? But it seems if I crank the petcock to PRIME, she'll fire back up... Is it bad to run the bike while in PRIME? and when I stop to turn it back to RUN or RES? Thanks everyone..

[daveo]

pull the petcock and see what kind of wonderment may have accumulated on the screens, check for full petcock diaghragm operation and good vacuum also

[Anonymous]

GS750

Sounds like either: (a) the tank vent is not working or (b) the screens on the petcock tube are clogged.
(a)- try taking a ride with the gas cap loose.
(b)- pull the petcock and check/clean.

[Anonymous]

Re: GS750

Sounds like either: (a) the tank vent is not working or (b) the screens on the petcock tube are clogged.
(a)- try taking a ride with the gas cap loose.
(b)- pull the petcock and check/clean.

Did (a). Same thing. Havent pulled petcock yet.. Will let you know on that.