at my wits end: gs1100e running on 3 cylinders

[billthebike]

my 6000 mile 82 gs1100e is driving me and my mechanic crazy.it will intermittently quit running on the #4 cylinder. sometimes it will start up on three (can hear the popping through the exhaust), other times while running down the road at highway speeds or less, will all of a sudden lose the #4 cylinder. carbs gone through and re-checked, gas cap checked, coils and wires tested, valves adjusted, no leaks at intake boots.
any suggestions? can a voltage regulator cause this? i'm ready to dump it and stick to my BMW's. I've owned this bike since may and have'nt put 400 miles on it.
Bill

[retchidxs]

i bet you did this but just didnt put it down on your list and that is the sparkplugs. i heard some of the guys in shop talk about plugs going bad it dont happen to much but it can.

[Throttlejockey]

i bet you did this but just didnt put it down on your list and that is the sparkplugs. i heard some of the guys in shop talk about plugs going bad it dont happen to much but it can.

I had a spark plug go bad on an 83 I had. The ceramic insulator cracked and was dropping down on the electrode causing an intermittant misfire.

I agree, replace the plugs.

[saaz]

I had something similar recently. Turned out to be bad spark plug caps. Wires and coils tested ok, but when it warmed up the spark stopped. Best to replace the leads and caps. I went through a few coils before figuring this out!

[Throttlejockey]

ive been lurking for a bit are those boots? if they are they were talking about those for plugs and they were only about 4 or 5 $ each. they have a resister in them i think this can go bad.

Years ago we used to take the resistor out and replace it with a piece of coathanger wire.

[82Shafty]

I'll give ya 100 bucks for it to take that headache off of your hands :-D

Popping through the exhaust does not necessarily mean that the cylinder quit.

What can be intermittent?

My guess would be that if four is constantly popping and the exhuast pipe is cooler than others and the plug indicates it being fatter due to incomplete combustion then cyl 4 definitely has a problem.

Popping out of the exhuast is usually from late ignition or a burn exhaust vavle. You also need to remember that this bike is based on the wasted spark theory so if 1 is firing fine than you atleast know the wires are doing their job of completing the circuit.

I'd say switch some plugs around to elimate or discover a bad plug.

[billthebike]

done the plugs, one of the first things i tried, no dice............

[ScottMc1100L]

...any suggestions? can a voltage regulator cause this? i'm ready to dump it and stick to my BMW's. I've owned this bike since may and have'nt put 400 miles on it.
Bill

I really doubt the regulator has anything to do with this but I do feel as if the problem is electrical.
When you pulled the plugs are they all look the the same, firing evenly etc. Any gas or oil fouling? Just sort of taking some guesses here.

[brveagle]

try switching the coil wires around and see what happens... that'd indicate if it was coil/fuel related.