Help! Running Out of Gas at High speed?

[canyon carver]

Hey Guys,

I have a 91 gs that sat in a field for 7 years! I pulled everything apart and cleaned then followed all instructions for rejetting on this site including 3 turns of air mix screw, washer under needle 125 mains etc. (awsome information on that whole process on this site-thank you!). Well, the bike now runs great at idle and pulls strong through the first 3 gears. On the freeway over 50mph however it shudders and feels like it  is running out of gas. If I gear down I can bring the rpms back up but only if I work the throttle up slowly. If I go full throttle it just bogs. It's a little unnerving being in traffic and shuddering and loosing power. I live in Utah at 5000ft and often ride in the mountains to 8500ft. Do I need to rejet for altitude? Do you think it is the petcock? Floats? Thanks for your help on this!

[davipu]

sounds almost like a starvation problem,  which it probably is petcock related,

[scratch]

As far as jetting for your altitude, you should be running rich, but not that bad, but it may explain why your carbs are running low on gas (fuel starvation). Do you already have the floats set so the fuel level is at the floatbowl gasket surface?

[scottpA_GS]

I have the same problem. My bike sat for 10 years.. I cleaned and did all the same. Now at high speed I loose gas as well. ( high speed for me is 60 or so )

I have read several posts and havent tried all the tests yet, but:

Did you put in a in line fuel filter? It may not be letting enough gas through.

Also the petcock may not be letting gas flow properly.

On my bike I am going to try taking out the fuel filter first. Then I will just try a straight line w/ no petcock as well.

Hope these Ideas help. I am still looking for answers as well

[canyon carver]

woops, As far as the floats, I kind of just put them back in the way they were without checking the height. My fuel petcock leaks ever since I had to clean the 7year old "gas" out of it. Maybe I should buck up and replace the petcock, fuel lines and adjust the floats. Could the air filter cause these problems too? :dunno:

[scottpA_GS]

I would try the simple things first.

remove inline fuel filter, ride w/ your cap open and fuel on PRIME as well. sometimes the tank vent is blocked. try removing the petcock. Also be sure that the petcock under the tank (there are 2) Make sure it isnt cloged, and its open all the way

I wouldnt buy a new petcock. The GS ones are junk from what most say on here. If you need. Go to a Lawnmower shop and get an inline shut off there.

I would however Use Kream in the tank.(yours had 7 years of gas mine had 10. And I had like giant gummy balls of gas come out of mine. I pressure washed my tank over 15 times.. Rinsed out all the crap. The Kream kit has acid to etch the tank, a cleaner, and the resurfacer. Its a kit you can get at the dealer about $35.00 . And replace the fuel lines, oil, filter, and plugs..

:0 i dunno, it worked for me.. The bike runs awesome.. except I do have that fuel starvation as well

[callmelenny]

There are a a lot of posts about this.

I ran into this recently on a long trip while running around 80+ mph for long periods. Flipping to prime on the petcock solved the problem for me. I don't usually ride that fast, that long so I decided not to worry about it.
The only danger of running in prime is that you could have leaks if you leave the bike parked and don't flip back to on.


I agree that replacing with stock petcock is probably not the best strategy.

[Kerry]

I live in Utah at 5000ft and often ride in the mountains to 8500ft. Do I need to rejet for altitude?

I live in Orem at 4,850 feet.  I have never rejetted, but I do have an in-airbox K&N filter with the restrictor installed.  I believe it flows a little more air than the stock paper filter.

I have ridden the bike in this configuration to the California coast (sea level) and up to Mirror Lake in the Uintas (10,000+ feet) just fine. :dunno: