GS 750 petcock issues?

[jmbpainting]

I have a gs 750 and fuel will flow from petcock on prime but not on "on"??
or reserve? Any help would be great.

Bike will turn over and run with help of starter fluid but won't stay running?

HELP!

[Pearson]

Congratulations, you're petcock is working perfect!:-D Many would give an eye to have your problem. But you probably don't have your vacuum line hooked up to the carbs correctly so it's not developing the vacuum needed to draw fuel in the ON/RES positions.

Do a search, this issue comes up a lot. Also tell us what year the bike is.

[kingofvenus]

Throw the starting fluid in the nearest trash can. Will it start with the petcock on prime? if not, you have a carb issue. If it has been sitting for a long time (like over the winter) drain the carbs of what is in the float bowls and install some fresh spark plugs, and try again with it on prime. If it still will not start you need to clean the carbs.

[chuckycheese]

Time?

If you can spare a couple of hours, do a search.8-[

[jmbpainting]

Its a 1981 gs750. It ran last summer, but was kind of a pain to get started if it sat for too long. I replaced the vacuum hose on it last summer becaseu the one on it was too short and kinked. When I throw the petcock on prime it will sputter, but it won't stay running. I also should mention that i didn't store the bike properly over the winter. No stabilizer in tank, and I tried to start the bike this summer without changing the gas. I'm guessing this was a lazy/stupid idea?? The tank is in fairly good condition inside. Should I see movement inside the carbs when i roll the throttle back? I looked through the hole where aibox attaches and i can't see any movement inside the two carbs i can see? Is this normal? I figured the flapper would be moving when it cranked the throttle?

[Dave8338]

All you're going to see looking there are the slides themselves and without the engine running, they won't move...they're vacuume opperated, like your petcock. Sounds like you may be in for a carb cleaning. Also, if you're trying to get it running well without the filter, you're in for a nightmare, to say the least. Will it start at all with just the choke? If not, you're going to need to make sure that the petcock is working the way it is supposed to and then work your way back from there.

Keep us posted.

[LostSoul3471]

Petcock wise, seems you have a good one and replacing the vacuum line is a good start to make sure your engine gets all the gas it needs. However if she runs rather sporadic or only runs with choke on, then like a few have already said, carb clean time. Berrymans is your friend. You might also check/clean your petcock too. I did mine this past weekend to make sure that everything was working in order and removed a good quantity of tar-like stuff from between the vacuum line plug and the 5 hole insert (regulator of sorts?) That may take care of some possible starvation issues I was having.

[chef1366]

Take off the fuel line on your petcock. Put on another one and put it in a bucket. Take a vacuum line and attach it to the petcock. Put the petcock on run. Suck on the vacuum line leading into the petcock. You should hear a click sound and the fuel should start flowing. Release the vacuum and the fuel flow should stop. If you get gas in your mouth get a new petcock. It should do the same on Res. Put it on prime and it should just flow.
If the petcock is operating properly you need to check the adjustment on your valves and clean the carbs.

http://www.thegsresources.com/gs_carbrebuild.htm

And replace the o-rings

http://www.cycleorings.com/

[GS750]

I had similar spluttery issues a while back, turned out to be the ignition (points and plugs) I replaced the points with a boyer brandsen electronic unit and used iridium plugs, havent had a problem since.

On my old CB250 honda, there was also the similar issue to what you describe with how its running spluttering etc, that ended up being the in tank fuel filter was blocked. Removed and cleaned it, started first go.

As a golden rule, I give my bike 500ml (half litre) of methylated spirits (ethanol) every 3 months, it breaks the surface tension on the water and allows the water to be passed through the filters and carbys without the particles bonding together and blocking filters / carby jets etc. it wont hurt your motor, it just burns off!

[jmbpainting]

Please go pee before you read on!!! May cause you to pee your pants!

So the moron i bought this bike from never showed me the proper start up procedure for this bike. So just for laughs i put the petcock on prime for about 5 seconds then back to on. I pulled out the choke and cranked the starter and the bike fired. I think my problem was I was flooding the bike out. Wooo hoooo! It's 80 degrees here so i took her for a ride around the block. I do have other issue though.

While riding I noticed the directionals would only blink if they bike was slightly above a normal idle 1700 rpms? As i returned from my twenty minute ride i stalled the bike and upon restart i noticed the battery seemed to have less punch than it did the first time? I've charged this battery a couple of times in the past and it is new as of last summer. I have very little confidence in my mechanic ability do change the stator. But I think i can manage to swap the regulator. what do you guys/girls think?

[Steve]

I think you need to break out your multimeter (you do have one, don't you?) and see exactly what's wrong before you start buying parts. The meter does not have to be digital, but they are nicer. It only needs to read voltage and resistance. Then do all the checks in The Stator Papers article found in the Garage section of this forum.


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[jmbpainting]

well i just figured from everything i've read about electrical issues its got to be the stator or regulator? I've gota 50/50 chance i guess. I'm about as good with a multimeter as i am with nail polish and panty hose. I laso need other things like new plugs and wires. any suggestions on a website that has good prices and great products?