Fluctuating Idle/Bogging/Backfire

[topherbarnett]

I really hope you guys can help me out.

My GS550 has been giving me a crazy idle for a while now. I know it's not an air leak problem because I sprayed all around the carb and airbox connections with carb cleaner and that never caused the idle to jump. It seems to rise fairly consistently after a throttle twist, but occasionally it will fall back down to normal.

Today I decided to go for a ride around the block anyway and about halfway around, she started bogging and backfiring out of nowhere like crazy. I was almost home when she died completely. Does all of this sound like a carb issue? I had them cleaned and sync'd about 6 months ago and I'm running a bit of seafoam in the tank now to clean out those winter "cobwebs". Also, I think I'm having a bit of an electrical issue with over-charging which I posted in the electrical section...could these be related?

EDIT: Forgot to mention there is a very faint smoke coming from the right tailpipe. Think that could be related as well?

Any help is appreciated.

-Topher-

[Dave8338]

Fix the electrical issues first and then move on to the carbs if they have been recently done. If you boiled the battery because of too much voltage, it will cause the battery to go dead, dropping voltage to the coils and in the end, cause the popping, backfire (as a result of delayed spark timing from the weak coil charge) and eventually die.

It sounds to me, like you have a few issues going on at the same time...

[krowe985]

as for the idle issue, i'm no expert, but i just went through the same thing with my 81' gs 650 g, my idle was doing that before i cleaned my carbs, in my situation, the previous owner had the air/fuel screws WAY up, and using a 3m Buffer pad as an air filter, it was very "Constricting", i found a better air filter that will fit in it, and lowered my air screws, now it idles "ALMOST" perfectly, it does jump a very little bit very randomly, but only by less that 200 rpms difference, so maybe this is why yours is idleing imporperly?

As for the popping, my carbs are doing that to right now, i'm thinking i damaged a boot going from the #3 carb (counting from left to right) to the motor.

Does it pop any when it is sitting there idleing? or is it just when your riding it?

[hampshirehog]

Are your carbs in synch?

[topherbarnett]

Well, I checked the battery right after and it was at 12.76V, so I don't think it had lost its spark unless my coils decided to knock out too. Compression is good as well, so that leaves me to believe it's a fuel issue, yes?

Like I said, I had a mechanic dip the carbs about 6 months ago and sync them as well after I had done the valves. Maybe he just did a crappy job and I need them redone.

[BassCliff]

Hi,

I know I sound like a broken record. I'm sorry. But you have a 30+ year old motorcycle. The maintenance lists in the "mega-welcome" are proven to usher you into GS nirvana, if you take no shortcuts. Yes, it takes time. Yes, it takes money. Yes, you'll have to learn a little about fixing your own motorcycle. Only then will you have a baseline for fine tuning your machine. In the end you'll have a reliable machine that starts instantly, runs smooth and strong, and stops on a dime. Keep us informed.


Thank you for your indulgence,

BassCliff