Runs out of gas after 20 minutes

[DieMonkeys]

So yeah, havn't worked on the bike for the past couple of weeks, figured I'd take a break.

But now that the coils are fixed, it runs great. That is, it runs great for about 20 minutes, towards the end of the 20 minutes it won't rev over 3000RPM and it chugs, and then it finally just putters out.

I can ride it, I have ridden it up and down the street, in fact, the faster I ride it the faster it runs out of gas. Now I know I'm not running out of gas in the tank, so I can only guess it's the carbs.

I have yet to do an adjustment to the floats, I know they're supposed to be 26mm (I believe, I'll double check the book later), but would this cause the gas to run out like previously said? If I adjust them all, would I be able to finally take my bike to school? (12 miles away).

[83GS1100E_Tornado]

Sounds like a classic petcock issue to me, are you sure it's OK????

[DieMonkeys]

Uh no, I don't think it's ok. It leaks when I take the hose off, it only has an on and reserve position. So I'm guessing it's busted.

[pntrdave]

Have you tried switching the petcock to prime? Then see if it runs out of gas. Other Question is... once it "runs out of gas" is it hard to start? or will it fire right up and run fine for another 20 minutes? Check your vacuum lines, make sure they are on tight and no cracks or leaks in them.

[DieMonkeys]

The petcock only has an on and an reserve position.

Again, only on and reserve. That's it. (Don't mean to sound rude, but I've mentioned it many many times and even after I mention it someone says "turn it to prime").

It is hard to start, in fact I have to leave it alone for a while before it'll start back up. The shorter I wait the less time it'll run, which is leading me to believe that the bowls are filling up, and the longer I let them fill up the longer the bike will run.

No cracks, I may be missing a hose clamp, I'll pick one up from work tomorrow just in case.

[earlfor]

Just for the hell of it, next time you start the bike, run it with the gas cap off.
You may have a clogged tank vent.

Earl

So yeah, havn't worked on the bike for the past couple of weeks, figured I'd take a break.

But now that the coils are fixed, it runs great. That is, it runs great for about 20 minutes, towards the end of the 20 minutes it won't rev over 3000RPM and it chugs, and then it finally just putters out.

I can ride it, I have ridden it up and down the street, in fact, the faster I ride it the faster it runs out of gas. Now I know I'm not running out of gas in the tank, so I can only guess it's the carbs.

I have yet to do an adjustment to the floats, I know they're supposed to be 26mm (I believe, I'll double check the book later), but would this cause the gas to run out like previously said? If I adjust them all, would I be able to finally take my bike to school? (12 miles away).

[robertbarr]

I had a similar problem with an 82 GS850. Below about half a tank it would start doing the same thing, and I'd have to stop and let it 'rest' while the fuel bowls filled up.

I checked everything even remotely connected to fuel supply, and everything looked fine. Out of frustration I removed the petcock and cut the strainer out of it. Voila -- problem solved.

(Except of course I now had no strainer on the petcock, but that never caused me any trouble -- unlike the strainer itself, which killed the engine in traffic about 300 times....).

HTH.

RB

[chef1366]

Fuel starvation. Petcock or fuel cap valve. Just get a new petcock because my bike did the same thing and the petcock was the culprit.
Clean the fuel cap with carb cleaner. Mke sure you can hear the ball bearing rattle about.
I'll keep an eye out for your petcock because it is a hard one to find.

[GS850_Coug]

Check the cap and the petcock/screen. It is unlikely all of your floats would go out of adjustment simultaneously (unless, of course, you fussed with them). If it was one or two floats, the bike would run, but very crappy. Most likely your screen is plugged or the gas cap vent is craped up. It's fairly simple to disassemble the cap and clean it up and put it back together.

[hp1000s]

Good one, Earl...I vote gas-cap. Next time it "runs out of gas", pop the cap and listen for the tupperware sucking sound.

[DieMonkeys]

Alright, just did the gas cap trick. I ran the bike with the cap on until it quit, it died rather quickly this time. Then as soon as it died I twisted off the cap, no suction, then I tried to start her up, she would only run if I held down the starter, and I wasn't going to do that for more than a second. All the hoses are secure (I believe, it's dark right now, I'll take a better look tomorrow). Next up, the petcock?

[earlfor]

Take the petcock off the bottom of the tank and check the screen on the pick up tubes. I had an old Ford pick up that almost drove me crazy trying to figure out why it would run for a half hour and quit and then be fine an hour later.
As it ran, drawing gas, it pulled sediment onto the gas filter screen, clogging it and causing shutdown. After shutdown, the sediment settled off the filter and the truck would once again start and run for a short time.

E.

Alright, just did the gas cap trick. I ran the bike with the cap on until it quit, it died rather quickly this time. Then as soon as it died I twisted off the cap, no suction, then I tried to start her up, she would only run if I held down the starter, and I wasn't going to do that for more than a second. All the hoses are secure (I believe, it's dark right now, I'll take a better look tomorrow). Next up, the petcock?

[Road_Clam]

Alright, just did the gas cap trick. I ran the bike with the cap on until it quit, it died rather quickly this time. Then as soon as it died I twisted off the cap, no suction, then I tried to start her up, she would only run if I held down the starter, and I wasn't going to do that for more than a second. All the hoses are secure (I believe, it's dark right now, I'll take a better look tomorrow). Next up, the petcock?

Sounds like you have a ton of rust sediment flowing around inside the tank. Take a flashlight and have a look at the inside tank walls. If you see a lot of rust, you have the imfamous "GS inside rusty tank, that starves the petcock of fuel syndrome" . The only true solution is to clean and KREEM the inside of the tank. You will also most likely need a complete carb clean as all that rust sediment has made it's way down into the carbs.