GS550 Extreme high Idle

[Lucky_Strike]

Hello everybody!

Mijn name is Ciaran and I am new to this forum, at least as far as introducing.
I've been reading entries and information on this site for some time now.

So let me start off bij thanking everybody in this community for sharing their knowledge.

Now for the main reason i started this thread.
I'm am the current owner of a 1980 Gs550. Which has a strange problem that has me at a loss.

The bike came to me running poorly, and we (me and a buddy of mine) decided to try and bring it back to life.
Cleaned the carbs, new oil new plugs, etc. Ran pretty good after that.
We then installed POD filters (I know a big no no, but to be honest its for the looks, i know it's near impossible to get the bike operating fully)
This ment we had to change out the main jets (went up two sizes).

Took it for a test drive, looked pretty good, until we started it back up the day after.

When i start the bike now, it imediatly revs up, not just a bit, but it sounds like some janked the throttle, and it just stays there. Offcourse we cut the bike of, because you dont want a cold engine to run a full throttle idle.

I'm at a total loss, as i cant find the problem causing this, i'll sum up the things we have installed / tried to do to fix it.


- 1980 GS 550
- Mikuni bs32 carbs
- POD Filters (reduced airflow by installing foam on the inside of the filter)
- Main Jets enhanced 2 sizes (from 92,5 to 97,5)
- 2 x 2 into 1 exhaust

To fix it we have tried:

- Checked that the throttle cable isn't stuck, even disabled it to be completly sure.
- Same with the coke cable.
- Bench synced the carbs, and after that dynamicly sync them.
- pulled carbs again and cleaned them (removed jets, dip + blow out)
- check butterfly valves for sticking, seems fine.
- Checked float levels and slides. Float are set to standaard and slide are smoothly opening and closing with "swoosh" sound
- Needle clip is in middle position (default as far as i know)
- Sprayed starter spray around the carb boots, doesnt seem to react to that.

The error to mee, seems like it should be a vacuum problem, but i cant seem to locate it.
I'm really hoping someone here can give me one or two pointers.

Sorry for the long babbeling, i'm trying to give as much information as possible.
Thank you in advance
Ciaran.

[Nessism]

Your jetting is off for one thing. Getting the bike to run properly with pods is a whole lot more involved than just bumping the mains two sizes. Dynajet makes a kit for the 550M which will fit your bike, so you might want to simplify the process by picking it up .

Typically a high idle indicates a lean idle mixture. Most common issue is leaking intake boot O-rings and/or boots themselves could be leaking. Spraying crap around the carbs to find leaks is an unreliable method. The 550 is quite lean when new and requires about 3 turns open on the pilot screws. Of course, this assumes the bike is stock so for a modified bike, you may need larger pilot jets. You need to vacuum sync the carbs too in order to get a properly stable idle.

My signature includes links to both a carb rebuild tutorial and the Newbie Mistakes threads. You might want to look through these to see what strikes close to heart.

Good luck.

[Steve]

I did not see mention that you tried to simply adjust the idle speed screw.

Also, the fact that you have adjustable needles tells me that you are not in the USA, or at least don't have a US-spec bike.
Please add your location to your profile, so we can make better suggestions on where to go for help.

.

[Lucky_Strike]

Sorry for the late reply, and thank you for you reactions...

Turned out te be a torn o-ring in the carb boot, replaced that and it came down enough, so that i could actually tweak it with the idle screw.

I'm from The Netherlands by the way, and i had already looked over the newbie thread.
As i suspected it to be a vacuum leak, but i couldn't pin point it.

Again thanks for the help and untill next time.

[tom203]

Those nasty boot o-rings! Thanks for update!