91 gs 500e cant start it

[MongMan]

Hello everyone
I just bought a 1991 gs500e with 37k miles on it, i cant seem to get a cough or choke out of it. I have been reading these forums for a while now and tried lots of different things, but im still a newb, and its my first bike.

Well first off it has spark on both plugs, i cleaned the carbs, and oil, checked the float bowls and they spill gas quite well. The man that sold the bike to me sprayed starter fluid in the valves and got the bike to cough a bit but thats all. He said all it needed was a good cleanin of the carbs. But it will crank all day without any signs of anything lol. i read something about putting a paper infront of the exhaust valves and see if it spits gas on it when cranking, so i tried it but paper was dry. Sooo, im assuming the valves arent sucking in the gas i put my hand on the carbs and they have suction when i crank the engine, unfortunately my compression tester doesn't fit.  Can anyone give me some ideas, i dont care about getting it perfect right now i just want to get it started no matter how crappy it runs then i can go from there.

[Jared]

Did you CLEAN The carbs .....

Remove the pilot jets and clean them so you can see through them ( or outright replace them). Clean all the orifices in the carb bodies..Cleaned the main jet  etc etc etc

Have a clymer manual yet?

[MongMan]

Yes i cleaned the jets and used carb cleaner and compressed air, i could see through all the holes. yeah i have the manual thats what i used.

[janeuner]

What about the air jet?  If that channel is clogged, you will never get the cylinders to fire.  

Edit: When you cover the air intake with your hand, fuel should spray out of the air jet due to back pressures.  If it is clogged, it probably won't spray.

[cboling]

I had a very similar problem as you have and I fought with it quite a bit. Here are some tips that you may want to follow.

1. Pull the carbs and clean them again. (I know, it is a pain but if you can locate the carb cleaning / rebuild how to, follow it.) The one thing that you will not see on that guide is a mention put a small wire through the tube that the floats cover. (Not sure if it is called an emulsion tube, or what but the floats when removed, will slide off of that tube.) Make sure to run a wire through that hole so that they are good and clear. All the other holes you can pretty well see through.

2. You can check the floats via the hose on the drain nipple of the float bowl. If it is correct and fuel is getting in there, chances are, the fuel is not being pulled through that tube I mentioned above.

3. If you put your hand over each intake and it sucks your hand against the intake pretty well, you should have enough suction. Simply cup you hand fairly tight to see if you can get fuel to pull through the 2 little holes on the face of the intake. If so, you will probably hear the bike try to start. Quickly move to the other intake and continue to push the start to try and get fuel flowing. If you are not getting enough suction, make sure the idle screw is opening the throttle just a bit.

The only other thing is to check all the orings and make sure they are there. The ones under the black caps on top of the carbs sit on the rim of the body and if they are not there, that could cause some problems I believe. in a pinch, you might find some small o-rings from the local auto parts store that will get you by.

Good luck, if you have spark and air, the only thing to figure is why the fuel isn't getting in.

[Jared]

Ditto on going over all of it again- you may have cleaned it ok and then still had a piece of crud in the fuel lines or the petcocks get something stuck in the pilots again...(Has happened to me before..). 

Gumout carb cleaner works well for me....(you can also shoot that in the air box and the bike will run on it for a few seconds....air filter out...).

Carbs/bikes are fun to diagnose over the internet...

Charge the battery up too and take a good look at the spark plugs again too....you want a nice easy to see bright spark... I've had perfectly good looking plugs  that were  crap...and crappy looking ones that work great.

Good luck.

[MongMan]

Ok so you guys believe it to be the carbs, then i will clean them again, oh yea i remember some gas squirting out of the air jet when i put my hand to cover the intake.  the spark looked kind of white in color, i know its supposed to be blue could that be why it wont start?

Well anyways thanks for the advice guys i will tend to the carbs.

[MongMan]

Hey cboling you were right! number 3 on your list worked! i put my two hands and covered the intakes and my dad pressed the start button, the biked fired and poped!! but no throttle response. But it still wont start on its own. I just wanted to ask you what should i do now to get it to run on its own lol?

[bill14224]

You need to follow cboling's advice and clean your carbs again.  When you put your hands over the intakes you were in effect adding a ton of choke, so the tiny bit of gas that managed to get through the carbs was able to make it fire with a ton of choke.  Your carbs are almost 100% clogged somewhere.  Clean them again, this time paying close attention to the emulsion tubes under the floats.  Those tubes draw fuel out of the bowls, so if they're clogged it would explain your problem perfectly.  Run a wire through them like he said.  You have air and ignition.  It sounds like you have good compression.  Your timing is probably fine.  Now you need fuel!  If your bowls are filling there's no problem from the tank to the bowls.  Check that too before you take the carbs off again.  It may save you some work.  When doing so keep the petcock on the PRI (prime) position.  If your vacuum-operated petcock is bad it won't allow fuel to flow in the on or res positions.

Clogged carbs, bad electrical connections, and weak batteries are the three most common problems on old bikes.  Keep that in mind.  Best of luck with it, and welcome to the board!