GS550ET irregular tickover

[Guest]

hello all,

quick question for you, if I may ...

GS550ET - Dutch bike now re-registered in the UK. Had been standing for many years before the previous owner rescued it, and then got it running and through the UK annual MoT check. I bought it from him 18 months ago, and changed old bits for new/better ones; fixed a number of faults etc etc. Finally got it ready for the MoT and took it in today - surprise surprise, it passed!

There was just one advisory comment - irregular tickover at idle. Oh yeah, don't I know about that one!! The bike starts, runs, accelerates really well, but just will not hold a steady idle speed. It will actually change while I'm out riding - one moment its 2000rpm, next minute it will stall.

My question is - how is the idle speed tickover adjusted on this bike? Usual manuals (Haynes, Clymer etc) just say 'use idle speed adjuster screw to set tickover'. I have tried using the idle adjust screw underneath the bank of CV carbs, and changing the throttle cable for a new one and tried to adjust from the handlebar. No joy. Before I take the carbs off for a strip down and clean, is there something completely obvious that I'm missing here?

Any advice appreciated - thank you.

[Steve]

Under the carbs, you will see a knob in the middle, between carbs 2 and 3.

Clockwise to raise idle, anti-clockwise to lower it.

I think your idle speed is specified at about 1150 ±100 RPM.

Regarding your changing speed, you might need to address an air leak. Prime culprits are the o-rings in the boots between the carbs and the cylinder block. Unfortunately, that means removing the carbs, which is a real pain on that bike. Then you have to remove the boots. Be careful, the stock screws that hold them seem to be made of aged Cheddar cheese, so be sure to use the proper driver bits. The proper bit is a #3 JIS, but a #3 Phillips will work well, too. You will likely have to use a hand impact driver to remove them.

O-rings and stainless bolts to replace the stockers can be found at cycleorings.com. I am reasonably certain that he ships across the pond.

.

[redliner]

Hi Steve,

thanks for the heads-up about those carb boot O-rings.
I've had a quick check to identify them - looks like Suzuki part number 09280-38003 (superceded by 38004) - will get some ordered up and give it a go.

[Rob S.]

A perfect idle on an old bike is a thing of beauty. It's also somewhat rare. As great and powerful as my '73 Z1 (Kaw 900) was, I never got it to idle low enough. The book said 900 rpm, but they were on acid when they wrote the book. I would have been happy at 12k, but it never idled well below 13 or 14.

I don't mean to brag (well...), but my 11E, once warmed up, holds a beautiful idle at a hair over 1k.

Good luck on your project. And listen to Steve - he knows.