GS550E Doesn't Function Well - Motorcycle shop "Stumped"

[Tenshots1]

Well today I put the O-rings in and no help. First, the o-rings seemed to be in good shape. A couple of them were hard, but they had good seal.

I put the bike back together, warmed it up, and the idle continued to be high once the bike was warm. Even with the throttle finger screw all the way backed off, and the choke off, the bike idled at 3-4K RPMs. I have no idea how. Fuel mix screw is only 2 turns out. I may try turning this in more to lower the idle, but 2 turns seems pretty standard.

Also, the thing is riding terribly. Strong dead spot below about 4K RPMs. Even after that, it doesnt seem like my normal power is there. The front of the engine started smoking a bit, like maybe it was running lean...

Any suggestions? I guess the next step for me is to break the carbs back down and put in all the old jets to see if that could fix it.

[tom203]

"Even with the throttle finger screw all the way backed off, and the choke off, the bike idled at 3-4K RPMs."

I'd pull the carbs and check the bench sync...maybe one or more the throttle plates are off causing one to hang/stick open too far giving you a high/erratic idle

[Buffalo Bill]

I had the same issue with my GS550T. I resolved it but it took some time. Sorry can't remember any secret issue, but worked with the same basics mentioned here.
Sold it and was so glad to see it gone. Decided to never buy a GS550 again.

[roeme]

(...)Decided to never buy a GS550 again.

Pshaw!

Anyway, OP, common thing to forget is to hook up the vacuum line for the petcock. Check that first.

Secondly, when having a VM22SS bank apart and putting them together, you absolutely must use threadlock (the kind you can break free again, for example loctite 221) on the screws fixing the
carbs to the carrier plate.

Thirdly, same on the screws which affix the butterfly looking part to the throttle shaft going through all carbs, and the ones connecting the plunger assembly to aforementioned shaft.

A 550 will rattle the carbs/parts loose otherwise, which results in the carbs moving around, preferably when you move the throttle, resulting in a throttle position offset, which in turn often results in a high idle and all other kinds of havoc.

Had the same issues as you, these were the root causes in my case.

[Tenshots1]

Pshaw!

Anyway, OP, common thing to forget is to hook up the vacuum line for the petcock. Check that first.

Secondly, when having a VM22SS bank apart and putting them together, you absolutely must use threadlock (the kind you can break free again, for example loctite 221) on the screws fixing the
carbs to the carrier plate.

Thirdly, same on the screws which affix the butterfly looking part to the throttle shaft going through all carbs, and the ones connecting the plunger assembly to aforementioned shaft.

A 550 will rattle the carbs/parts loose otherwise, which results in the carbs moving around, preferably when you move the throttle, resulting in a throttle position offset, which in turn often results in a high idle and all other kinds of havoc.

Had the same issues as you, these were the root causes in my case.

Interesting point. I will check my throttle plates and look for any loose screws. I agree that it seems like something is causing the throttle body to stay open.

[Steve]

Secondly, when having a VM22SS bank apart and putting them together, you absolutely must use threadlock (the kind you can break free again, for example loctite 221) on the screws fixing the carbs to the carrier plate.

Very good advice, but does not apply here.

His 1980 550 has BS32SS carbs.

.

[Redman]

Well today I put the O-rings in and no help. ............

I gather you are refering to the Carb boot O-rings (up against the head).

I had hanging idle like you described, replaced the carb boot orings, and that took care of the problem.

THen a few years later it came back - worse.
GOt the carb o-ring kit, and replaced all the carb o-rings that I could without breakaing carbs down from the rack, meaning; did not replace the orings around the enricher (choke) plunger.
Didnt help.
SO I tore them down further, broke the carbs apart from the rack, replaced the o-rings around the enricher (choke) plunger, and THAT took care of the high hanging idle. At that same time, since carbs were broken down to individual carb bodys, I also gave each a 24 hour soak in berryman carb cleaner, and that took care of some other carb related stumbles.

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