'80 GS1100E - #2 cyl won't fire-carb suspected

[Etchii]

Hi everyone,

I seem to have a problem with my GS1100E where the number 2 cylinder won't fire, at least while idle. The bike smells like it is running very rich and i keep fouling plugs in this cylinder. The plug comes out very black and wet with fuel.

I had a shop clean the carbs for me (supposedly) and they put an in-line fuel filter in for me, which is still clean.

I drained the fuel out of the carbs today and it also looked clean... i'm thinking maybe an air mix problem?

I'm not very knowledgable about this stuff but i'm slowly learning as i go. You guys & this site are a great resource by the way.

I saw on the carb rebuild section an air screw... i'm probably way off but does this limit the ammount of air in the mix? is mine possibly in too tight?

The odd part about this whole thing is when I put a brand new plug in that cylinder it won't fire while idle (quick spray of water on the pipes to check) but after reving it 3-4k it seems to heat up, but stops when below this RPM.

[82GS850]

It might be electrical. I have an 850 that lost spark to the #3 cylinder. Traced it to a bad ignition coil. Pull the plug and check for spark. With the plug laying on the cylinder head crank the engine and check for a bright blue spark. If no spark I would suspect a bad coil.

[Dave8338]

Sounds like a petcock that needs replacing. Do a quick search on this and you'll find it to be a VERY common problem.

[moto_dan]

Another vote on either repairing or replacing the petcock. Check by pulling the vacumn line off the #2 intake after running and it will probably be wet with fuel.

[Etchii]

It might be electrical. I have an 850 that lost spark to the #3 cylinder. Traced it to a bad ignition coil. Pull the plug and check for spark. With the plug laying on the cylinder head crank the engine and check for a bright blue spark. If no spark I would suspect a bad coil.

Thanks for the responce!

I pulled the wire from the #2 plug and used a spare plug to check, I have spark. It looked kind of weak but so did the #1 plug wire, guessing it is ok as that cyl is having no issues.

[Etchii]

Another vote on either repairing or replacing the petcock. Check by pulling the vacumn line off the #2 intake after running and it will probably be wet with fuel.

I'll check this next. Thanks for the tip with the vacume line.

This is my first bike and holy crap its fast with just 3 cyl... I'm almost scared to get it working 100% lol.

[Gent]

Etchii,

I had the same problem with # 2 not firing, carbs were clean and rebuilt (new floating needles, jets, gaskets) new petcock as well. Spark was strong but still not firing on # 2. Very rich on 4 plugs and #2 was wet. I noticed the oil level was raised as well, gas was mixing with oil. And after all troubleshooting I did finally I found the problem. It was the gas was to high in the bowl. So I adjusted the floating lip to the proper hight wich is 0.88 of the inch. You should get this info from the GS1100E service repair .pdf file.

Hope this helps.

[Etchii]

Update:

I pulled the vac hose off and it was hard to tell if there was fuel or not in the line.

I ran the bike with the hose off and the cyl fired up! (until i ran out of gas). I played with the valve a bit and when the vac hose was off and the valve in the prime position fuel was flowing out of the vac hose port on the petcock valve.

Bike started smoking up a storm as the #2 cyl fired up, lots of buildup in there from not firing i guess.

I am going to try to replace the valve. I don't think my tank is the original so i'm worried about finding the right one. Previous owner thinks the previous owner to him put a 750 tank on the bike.

[Etchii]

Etchii,

I had the same problem with # 2 not firing, carbs were clean and rebuilt (new floating needles, jets, gaskets) new petcock as well. Spark was strong but still not firing on # 2. Very rich on 4 plugs and #2 was wet. I noticed the oil level was raised as well, gas was mixing with oil. And after all troubleshooting I did finally I found the problem. It was the gas was to high in the bowl. So I adjusted the floating lip to the proper hight wich is 0.88 of the inch. You should get this info from the GS1100E service repair .pdf file.

Hope this helps.

Not sure how to adjust that lip but i'll find out if i need to go to this step (trying petcock first).

Happen to have an 1100e .pdf file?

[reddirtrider]

Not sure how to adjust that lip but i'll find out if i need to go to this step (trying petcock first).

Happen to have an 1100e .pdf file?

I usually use a small screwdriver to tweek it if the float height isn't correct.

[Etchii]

I usually use a small screwdriver to tweek it if the float height isn't correct.

can you do this without disassembly?

[Etchii]

Petcock did it! You guys rock. Repaced the valve and the #2 fired up, smoking like hell right now but that should pass.

As for performance....Holy crap, its like an entirely different bike!

[mistertoadie]

I believe this is what killed my motor. The vacuum line from the petcock kept leaking into the #2 cylinder causing piston wash and led to a seizure. The po got it freed up but it totally pooched the bore. Smoked like a pig all the time.

[Etchii]

Ouch!

I'm happy to report the smoking stopped after a short hard ride. Going for an oil change this weekend, 100 miles then another change just to be sure.

I'll try to get some pics for you guys this weekend. She isn't much to look at as of now but i'll get there.

Next up...electrical! Rear light is bright 100% of the time, no change when braking and my turn signals work 50% of the time lol.