1980 GS550E - Lack of throttle control

[yellow]

First thanks for all the advice I got previously about this bike. I was super frustrated because I could not get it too work at all for the winter. Well it was 50 out today and I said what the hell....IT WORKED...she fires up and idles at about 1500....i was not an idiot (well not complete). But the throttle is sluggish. BUT all 4 cylinders are firing (pipes all warm). Better than the 2/3 previously.

My question is what would cause the throttle when turned to have a couple second delay and then rev way up?

Thank you. Andy

 

[yellow]

Things are better....

Things are better....

Well, decided to play the patience game....figured she has not been run in a while and that she has the right to stretch her legs....HELPED A TON....throttle responds appropriately now....just idles high after warming up. gonna try the wd40 near manifolds....

 

[KEITH KRAUSE]

You have the classic symptoms of an intake leak. Even if spraying doesn't expose a leak, you have one or more.
Try tightening the manifold clamps first. You may be lucky. If it still has the problems you describe, check the manifolds and any o-rings they may use. The problem should be there.

 

[AOD]

I had a loose bolt on the shaft that picked up all the slides in my old carbs, which would cause the idle to stick a little. I'd have to rock the throttle to get it to idle. Only when I rebuilt the carbs did I catch what was wrong.

I liked an idle of 1500-2000 on my 550. When cold it was about 1500, when warm 2000 with the choke off. Sure it ran at a lower speed, but with such a small engine, it's not hurting it to idle slightly higher.

I like the way my 1100 idles at 1500 instead of 1000 too.

~Adam

 

[KEITH KRAUSE]

Not knocking you Adam, and to each their own.
But an idle of 1,500 to 2,000 shouldn't be necessary or used. It's harder on the clutch, harder on the trans, and harder on the brakes. Also makes hot weather stop and go driving harder on the motor.

 

[yellow]

You have the classic symptoms of an intake leak. Even if spraying doesn't expose a leak, you have one or more.
Try tightening the manifold clamps first. You may be lucky. If it still has the problems you describe, check the manifolds and any o-rings they may use. The problem should be there.

Thanks for the response Keith, I will try tightening the clamps. What O-rings?

Also, I am adjusting the idle it the idle know in the middle of carb cluster. Is this a bad idea. I understand that once i find the leak, I should be good and not need further adjustment.

Thanks again-andy

 

[yellow]

I had a loose bolt on the shaft that picked up all the slides in my old carbs, which would cause the idle to stick a little. I'd have to rock the throttle to get it to idle. Only when I rebuilt the carbs did I catch what was wrong.

I liked an idle of 1500-2000 on my 550. When cold it was about 1500, when warm 2000 with the choke off. Sure it ran at a lower speed, but with such a small engine, it's not hurting it to idle slightly higher.

I like the way my 1100 idles at 1500 instead of 1000 too.

~Adam

Adam, thanks for the input. the throttle is not sticking...checked. thanks-andy

 

[KEITH KRAUSE]

Thanks for the response Keith, I will try tightening the clamps. What O-rings?

Also, I am adjusting the idle it the idle know in the middle of carb cluster. Is this a bad idea. I understand that once i find the leak, I should be good and not need further adjustment.

Thanks again-andy

The manifolds have an o-ring to seal against the head. It sits in a groove. The manifold screws, if stock Phillips, can be stuck sometimes. Carefully remove them and replace with Allens.
Inspect the manifolds. If supple enough and no cracks, you're OK. If cracking/hardening, they should be replaced. Manifolds go for about $25/ea new.
More commonly, the o-rings will flatten out and crack. They almost certainly need replacing. They're too cheap to re-use. Be sure to get Suzuki brand or equivalent. Apply some hi-temp bearing grease to help them last and torque the new Allens to 6 ft/lb or what your Suzuki manual states, if it states at all.
Your high idle problem is most likely an intake leak.
Yes, your idle adjuster knob should be in the middle of the carb bank. It should be adjusted (on a bike with no intake leaks) when the bike reaches normal operating temp. It can be adjusted while cold, but expect about 100 to maybe 200 rpm gain once warmed up. No older bike idles the same rpm when cold and fully warmed up. But if it rises significantly, that's an intake leak.