right side cylinders cut out at wide open throttle

[clancytenley]

I am hoping someone can help me with this problem with my 1983 GL1100.

The symptoms: Bike runs great except at wide open throttle, when the two right side cylinders both cut out. Both right side plugs show evidence of rich fuel mixture after only a day of use.

What I have done: I just purchased this bike after it had sat idle for three years. I replaced the fuel filter, took off the carbs, and cleaned the jets but did no other carb work. It ran great for a day and then this problem started. I cut off 1/8 inch from the plug wire ends to make sure I had a good connection and checked the resistance in the coil primary and secondary, wires, and caps. All within spec. The plugs are new and correctly gapped. They show spark when removed and tested. I thought a coil was the problem until I saw that each coil serves both sides of the bike.

I am thinking that there might be some problem with the two right side carbs. IS there something that could create these symptoms in both right side carbs at the same time?

Thank you for your replies.

 

[zman]

They could be starved for fuel under wide open., I would drain the bowls after a ride and see how much comes out. Yes they are a pain to drain but you can fabricate some kind of catch basin to put under there.
Also if the fuel level checks out it could also be a clogged screen under the float not allowing enough fuel to enter under a hard load.

 

[joedrum]

welcome to classic .....might be that plastic straw deal that cut gas flow to that side between the left and right carbs sets .... but it could be other things too ....

these carbs have so many quirks it really hard to say :swoon: :mrgreen:

 

[Steve83]

Welcome from SoCal! Along with the carb issues, check the fuel pump output, and for any restriction in the exhaust system.

 

[mcgovern61]

Welcome to the site from New Jersey! :clapping:

 

[OldWrench]

Welcome to the site from California. You said your plugs were showing signs of a rich mixture, I'm wondering if you are flooding the right side. You said you took the carbs off and cleaned the jets, did you balance the carbs when you put them back on? Also did you replace the 40 mm O-rings of the intake tubes? Ok, I'm out of guesses for now.

 

[clancytenley]

Thanks all for the welcomes and good ideas. I didn't replace the intake o rings or check the little plastic flow restrict or tube. I am thinking of taking off the carbs now to do that as well as a more thorough overhaul than my first cleaning. Can anyone recommend a good overhaul kit with the I rings etc? Also, any thoughts on whether the air bypass valves could cause this? I thought it unlikely that two would go out at once but I have read that they can cause an overly rich flow at WOT. Thanks again for the suggestions.

 

[joedrum]

hmmmm it seems that could cause it ... its just worth breaking it down and find out what things look like .. before buyin stuff .. i just got finish fixing a leaking rack that really only needed four o rings and the four four mix screws ... thing runs great now ... oh and the o rings were missing on the nix screws on all four ... the kit was one most people blab as no good ... it had jets and all .... it seemed it was quite expensive as i look at things i always try and fix on my owe first as you did but id say try again ...it rather easy to see if the rubber is good on air cut offs .. and rather easy to do fow and stop test with carb off an gravity feed tank .. for flow and float stop tests

 

[Joep]

Welcome from North TEXAS DFW area...

 

[clancytenley]

Went through the carbs yesterday in more detail. Replacing air cut off diaphrams and then will sync it when back together. Keeping my fingers crossed. Thanks for the help.

 

[Ansimp]

Welcome from Oz

 

[clancytenley]

Well I finished going through the carbs, including replacing the air cut off diaphrams and checking the fuel levels in the bowls. I put it back together and then synced the carbs. I still have the following condition: the bike runs well at all speeds for the first three or four miles. After that it will sputter a bit at wide open throttle. If I let off the throttle and then slowly increase speed it will run well up to 90 mph. I am stumped. Any ideas?

 

[Ansimp]

Weak spark and or faulty advance mechanism.

 

[Steve83]

As I said in post #4, have you checked the fuel pump output, or for any restriction in the exhaust system? Or in the fuel tank or lines?

Try pulling the small rubber hose from the #3 carb and suck on it, you should hear the advance unit move, and it should hold vacuum. The pulser/advance unit is at the very rear center of the engine.