Hello everyone,

i am having problems with my gs 500 from '92, and i hope someone can help me out.
The problem is that 1 cilinder isn't running, but it does get a spark and fuel.
When i start the bike 1 cilinder runs fine and the other one doesnt run, causing fuel to leak out of the exhaust. ( it leaks a lot)
I already checked the pick up sensor, the ohm values are ok. (between 250 and 420 ohms.)
Although the 2 values are not the same amount of ohms, but that shouldnt be a problem right?

i cleaned the carbs multiple times, but i couldnt get the idle jets out, i cleaned them as good as possible.

i swapped the ignition coils and they both work just fine.

i personally think that the cilinder gets way to much fuel which results in the fuel leaking out of the exhaust.
This problem occured while riding, i lost power and the fuel was leaking.

I hope someone can help me out!

Jelle

Have you checked the compression of the cylinders?

And when you say fuel is leaking out the exhaust, are you talking about the muffler? 

I checked the compression with my hand, the compression seems good and the same for each cilinder. The fuel leaks out of the exhaust between the headers and the muffler, i have an laser exhaust.

Sticking float valve causing flooding ?

What do you mean by that?

The pins on the float needles are not stuck if that is what jou mean

Maybe there is some wear in one float needle causing it to stick open a bit and flood one cylinder ? Easy way to test is drain the petrol from both carb bowels and see if the quantity is the same. Or look for look petrol in the air-box and manifold.

I have ordered New needles and seats just to be sure

New needles and seats didnt solve the probleem
Does anyone else has ideas?

Up

Hi,  I'll take a stab.

Are you sure the gas is coming from the header/muffler connection? There is a drain hose from the airbox that drains overflow fuel, and that hose ends about where the mufflers would join headers on the right side.

Logically the only place that gas can be coming from is from the float bowls. If the float is coming up, then the problem will most likely be at the seat seal where the needle presses down on. As you indicate you have addressed this.

The second options is that the float is not coming up. This could be due to a leak in the float (it gets full of gas and sinks.), or a very badly adjusted float height (although floats seem to tend to  drop, rather than raise the fuel level over time), or a gasket or something interfering with the free movement of the float.

Try swapping the bowl and float from left to right (Hint : if you use Allen key type screws on carb bowls you can do this without removing carbs)

Good luck

Skipping over what's been addressed/suggested, have you checked the float height?  You can do it without removing anything, all you need is a bit of aquarium air tubing or similar. 
http://www.bbburma.net/FloatHeight.htm

You may find that one of the floats is so out of adjustment that it's basically free flowing fuel into the carb body which is then leaking out wherever.

I checked the floats and they do not leak.
Tomorrow i will check the float height, they seem the same for both carbs.

i have the same problem, yesterday removed the carbs, cleaned them pretty good with carb cleaner and replaced O Rings and the bike is running better then earlier but not perfect and its popping, disconnected left spark wire and bike stalls, disconnected the right side spark wire and nothing happened  removed the spark plug and it has very good spark also compression on right side seems good (just tested with finger on it).
may this be just a carb sync issue?
when i twist the throttle idle stays high 3-4k rpm, please help   

Quote from: galusta on September 18, 2018, 11:51:24 PM
i have the same problem, yesterday removed the carbs, cleaned them pretty good with carb cleaner and replaced O Rings and the bike is running better then earlier but not perfect and its popping, disconnected left spark wire and bike stalls, disconnected the right side spark wire and nothing happened  removed the spark plug and it has very good spark also compression on right side seems good (just tested with finger on it).
may this be just a carb sync issue?
when i twist the throttle idle stays high 3-4k rpm, please help   

Right cylinder should be dead with no spark to it.  So if no difference with that test, I'd guess you're bike has only been running on the left cylinder alone.
I'd check that gas is actually getting to the right cylinder.  Does it run differently if you spray starter fluid in the right carb?
The carb sync would affect smooth running, but it would have to be really badly out of sync to kill a cylinder altogether.

There's tons of threads about a "hanging idle".  Usually that represents a vacuum leak somewhere.
What jets are you running, and any modifications to air filter/ exhaust etc?

Pull your plugs and let us know what they look like. (photos are best )

i have good spark at the right cylinder, there is no spark problem and on high rpms i feel like the right cylinder is coming alive while riding, i have not tried to spray starter fluid i`ll do it later today. jets are stock, air filter and box are stock, exhaust pipes are stock with Akrapovic muffler

Quote from: Endopotential on September 19, 2018, 03:37:22 PM
There's tons of threads about a "hanging idle".  Usually that represents a vacuum leak somewhere.

While the RC may be vacuum leak or some other thing, the actual CAUSE of the hanging idle is that the idle is set to run too fast. Regardless of RPM, it is because the idle speed throttle stop screw is set to keep the bike from returning all the way to idle by blocking the throttle plate open a little bit (too much).

Now, often times the well-meaning owner will get the "idle speed" set this way to compensate for some other problem, like a vacuum leak or lean idle or clogged jet or a handful of other things.

OP: you can get rid of hanging idle by lowering the idle speed. But you have worse problems if it's only running on one cylinder, fix those first. It's probably not related to the carbs at all. Compression, spark, bulk fuel delivery.