Total Motorcycle Community Forums

Hi guys,

Short time reader, first time poster. *rimshot*

Anyway, I am a new biker and I just recently got my 1980 Suzuki GS250. It runs nice and strong and mostly works just fine exceot when it gets hot, the idle races and runs about 3500-4000rpms. If I get a chance to cruise for awhile, it settles back down to 2000-2200 or so. I know that's high anyway, and I need to adjust it, but what is causing the racing? The bike is air-cooled, so is it overheating in traffic? Is my choke broken and always on? What's the deal?

Thanks!

Update: I played with the throttle stop screw tonight and I got the warm idle to around 1800, but there seemed to be absolutely no effect after that point.

But now, I took it for a ride around the block, and the throttle hangs, and eventually (probably 4-5 seconds after closing throttle) returns to idle.

WTF. I know I need my carbs cleaned...would gunk in the idle circuit be causing all these gremlins and should I just knock off the tinkering until I clean the carbs first?

Sounds like there might be an air leak. Check around the boots for cracks etc.

You may need to adjust the pilot screws on your carbs to allow a richer mixture at idle. But only mess with this if you can rule out an intake leak like Sev mentioned.

Probably not a bad idea to lube your throttle and choke cables as well.

Don't turn the pilot out more then 5 full turns. At that point it's possible that the screw will vibrate loose in normal running conditions.

Bump this back to the top.

Things I can rule out:
Carbs
Air leak at intake manifold/carb boots

What else could be doing this? Any other locations for air leaks? I read somewhere that the springs on the timing advance might be worn out, and sagging when hot, and thus advancing the timing at idle. Is this possible? If so, I could theoretically cover up or at least lessen the problem by using a higher octane gas, right?

Air leaks arent alway's easy to find.I would spray water mist around the boots where they connect to the cylinder.Go to your local dealer and order the intake boot 0-rings.They get hard and brittle and will not start sucking air till it gets warmed up.Spraying around the boots will not detect this,believe me.I know! They are cheap, abot 2 bucks a peice and a good place to start.Start simple and go from there.You will spend a lot less money that way.Also go to www.thegsresources.com for all the info you will ever need on your bike.