'81 GS550T idle and high rpm issue

[heater63]

I just finished rebuilding my carbs and and I'm having a couple issues. I'm having trouble holding a good idle. I need to keep the engine at like 2000-2500 rpm to keep it from dying. If I hold it at 2500 rpm and release the throttle for a second and then try to rev it, it won't recover, and will usually die. The other issue is that the engine tops out at about 6000 rpms. Thats with the throttle fully open ..... it won't exceed 6000 rpms.

I believe I adjusted my pilot screws correctly, but could this be the source of my problem? I tried going through the top 10 newbie mistakes to eliminate any obvious causes.

Any suggestions? Thanks for your help.

[hampshirehog]

Airbox in place?

[heater63]

Yes. The stock airbox is in place. I also installed a new foam filter.

[hampshirehog]

Is the choke closing off properly?

[MisterCinders]

Are all cylinders firing?

valves adjusted?

[heater63]

The choke rod appears to be moving properly and properly closing. I believe all cylinders are firing. However I just replaced both of my coils with Dyna DC1-1 coils. (cylinders 2 and 3 weren't firing so rather than replace the one bad coil I replaced both). The outputs on the Dyna coils did not specify which output went to which cylinder. So I didn't think it mattered. Maybe that was a bad assumption. So the left coil is still wired to Cylinders 1 & 4. And the right coil is still wired to Cylinders 2 & 3. But as far as which output on the individual cylinders goes to Cyl 1 and which goes to Cly 4, I unsure. That being said the engine sounds like its firing correctly. But I could be wrong.

[MisterCinders]

Are all four headers hot?

[heater63]

Yeah. All the headers are hot. So I assume they are all firing. Could the firing sequence be wrong because of how I wired the coils?

[koolaid_kid]

Your coil connections are fine. Both wires on each coil fire every time that coil fires. That is, 1 & 4 both fire, then 2 & 3 fire, then 1 & 4, etc. I think you get the idea. So you are good at that point.

[Badooka]

6000 isn't near enough- you may need an assistant for this check- make sure your slides are opening all the way when you open full throttle. An inspection mirror and light might help too- depends on your help. I'm in a similar situation with my newly rebuilt engine/carbs with idle creeping and difficulty synching.
I suspect vacum leak at the airbox since the boots are really stiff and clamps are not healthy looking- these temps have me on hold-
I remember reading someone with a foam filter over oiling it and what you described too- he washed it out and lightly oiled and fixed it. Try that first if it applies.

[Nessism]

Did you take the carbs fully apart, soak them in dip, and reassemble with fresh O-rings? Replace the intake boot O-rings? Valves adjusted? Set the pilot mixture screws at 3 turns open?

6000 isn't near enough- you may need an assistant for this check- make sure your slides are opening all the way when you open full throttle. An inspection mirror and light might help too- depends on your help. I'm in a similar situation with my newly rebuilt engine/carbs with idle creeping and difficulty synching.
I suspect vacum leak at the airbox since the boots are really stiff and clamps are not healthy looking- these temps have me on hold-

There is no need to go though all that. Just rebuild your carbs properly and check the parts while everything is apart.

[heater63]

I did take the carbs fully apart. I soaked all metal parts in carb dip. I replaced all the gaskets and o rings. My pilot screws are 2 1/2 turns out. I did not adjust the valves though. I didn't replace the O rings on the intake boots. The thought about removing the boots but I thought I was going to strip the Phillips screws that secured them. I decided not to try and remove them until I knew I had to. They boots look to be in decent shape.

[Steve]

Where are you? There might be a member close enough to help you.

.

[Nessism]

I did not adjust the valves though. I didn't replace the O rings on the intake boots. .

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[hakim5857]

Hi heater63, follow all the tutotial & guideline that had been given. Previous i just let my mech to do it (biggest mistake but no option) but now i DIY my self with the guideline & tutorial from GS resources members. Now my GS run great and healthy. There is no easy way to ensure the GS run well... you can read my hard journey with my GS in the GS story section.

Happy DIY...