Poor Performance Upon Warm Up

[Jebus23]

Just finished a valve replacement job and replaced the exhaust gaskets on my 1980 GS550E. It seems to be having the same issues it was having prior to me putting it away at the end of last season. After the engine warms up it has a problem staying running. Any load put on the engine results in a bog, and any throttle given just kills it. I have cleaned and replaced o rings on the carbs, the bike has new stator, rectifier, dyna s upgrade, exhaust gaskets, air filter, plugs, new gas this season. What is my problem? Last season the bike would run well for about 40 minutes and them just bog down and die. It would not run again until I let the engine cool.

[BassCliff]

Hi,

The symptoms you describe sound like there is still gunk in the carbs. Clogged pilot jets perhaps?


Thank you for your indulgence,

BassCliff

[83gs1100g]

possible a weak and collapsing fuel line or vacuum line??? check or just replace'em?

[chef1366]

Compression?
Ignition?

[Jebus23]

I am doubting a problem with the carbs since they have been cleaned twice and thoroughly. The problem seemed to be on a ~45 minute delay last season although now the bike just seems to not want to run when its warm. Just before the bike has this problem there is visible smoke coming off the engine and it is not really easy to locate. It does not seem to be under pressure ruling out an exhaust leak. I really am losing hope on this bike. It has been a two year project and I haven't been able to enjoy it for more than a day at a time. I seems I have replaced half the parts on the bike with no luck.

The charging system is new and the dyna s should have given it better ignition.

I have yet to run a compression check but plan to very soon.

The weak or collapse line would make sense I suppose. The fuel line is new when I cleaned the carbs but the vacuum line may be collapsing when it warms up from the engine heat. That seems like it would be a fit?

I have searched this problem and it seems another fella fixed similar symptoms by replacing his coils and signal generators. I have the dyna s so signal generators are out but does this sound like a common coil failure?

Does this sound common at all?

I love this bike and would love to see it in its prime but this is exhausting now.

[Jebus23]

Anyone? Anyone? Could use more ideas/further discussion.

[BassCliff]

Hi,

You said "valve replacement". Did you really mean that? Or did you mean a valve clearance check and adjustment? Is there any rust in your tank? Are you using an inline fuel filter? I'm still thinking carbs here. Did you completely disassemble them and dip the bodies in Berryman's chem dip (or similar) for 24 hours each? Then you must use carb cleaner spray and an air compressor to make sure all the little passages are clean. CLICK HERE for the proper carb cleaning procedure. See the "Electrical Odds and Ends" section of my website for ignition troubleshooting tips. Have you done a compression check? Have you replaced, or tested, the petcock?


Thank you for your indulgence,

BassCliff

[Jebus23]

The carbs are clean.

It was a valve adjustment (shims).

The fuel petcock is brand new and was no visible rust in the tank.

If it was the carbs I would have a continuous problem, not the intermediate one with a sometime 45 minute delay, no?

I think the key here is the warm up.

If you think the carbs are the issue can you explain how this behavior is resulting? Especially with the heat.

Yet to do a compression check.

[TheCafeKid]

The carbs are clean.

It was a valve adjustment (shims).

The fuel petcock is brand new and was no visible rust in the tank.

If it was the carbs I would have a continuous problem, not the intermediate one with a sometime 45 minute delay, no?

I think the key here is the warm up.

If you think the carbs are the issue can you explain how this behavior is resulting? Especially with the heat.

Yet to do a compression check.

Have you checked your plugs?? I am struggling with a carb issue like Ive never encountered on a 550 myself. For whatever reason, and I have yet to find the solve, the bike, with stock jets, stock airbox and exaust in EXCELLENT shape is fouling plugs at idle like hotcakes. Even with the adjustment screws nearly CLOSED, its running exceedingly rich on idle. The petcock is functioning as it should, so I have ruled out that. The needle valves have little to no wear, so they SHOULD be seating properly. The carbs were cleaned as per the GSR mandate. The float levels I reset after I found them to be a bit off, causing fuel to leak into the airbox.

At any rate, it IS a possibility that you may be rich somwhere in your circuits. As the bike warms up, they will become even more rich, and cause bogging, sloggy running or just plain die.. Smoke coming off the motor doesnt seem to suggest this however.. Id take a look at your plugs..maybe post a couple of pics. Plugs seem to be the window through which you can tell alot about whats going on in your combustion chamber..

[Jebus23]

new symptoms:

there is exhaust coming out of my airbox!

I searched for what this means with no luck.

Pictures of spark plugs to come

What could the exhaust mean?

[Jebus23]

also:

I thought maybe my mixture screw is not turned out correctly. currently its 3.5 out. I am seeing 1.5 turns out though when I search. Can someone confirm this. Also, is this the only screw that needs to be adjusted (the one on top of the carb)

[Danjal]

Apply choke once and see if that helps. After that pull the boots to the airbox, see if that helps. Then pull your exhaust.

[Jebus23]

really need to know why smoke comes out of my airbox. i feel like this is the key to solving my issue.

[Jebus23]

CYLINDER 1



CYLINDER 2



CYLINDER 3



CYLINDER 4

[chef1366]

Exhaust out out of the airbox?
Check valve clearance if it isn't too late.