erratic idle after warm-up

[Afzzr12]

when I first start the bike it barely needs the choke and it will idle fine.  AFter about 5-10 mins of going it starts to hold the idle at 3k-4k rpm.  It doesn't matter what I do it will not go down unless it just decides to.  I have not dug into the carbs yet because I just bought it.  It is a '95 GS with 19,000miles on it.  The previous owner said he had the suzuki shop in town go through the carbs, but obviously somthing still isn't right.  I replaced all of the fuel lines, put in new inline fuel filter, and cleaned a lot of external stuff.  I'm stumped on this one.  As far as I know all the parts in the carbs are stock.  Please help!!

Alex

[scratch]

Welcome!

Because it barely needs choke to start, it's too rich.  But because it idles at 3-4k, there could be an air leak.  But, finally, it's neither of those; the idle has not been set correctly.  After 10 minutes, or 15 minutes of riding, whichever is safer, set the idle to 1200rpm.  The screw is located between the two carburetors, it's the brass knob hangin' down between the floatbowls.  Picture soon.  It's easier to get to from the right.

[Afzzr12]

Well, I guess I left out a couple of things I have done before I posted that.  I checked the float level using the "U-tube" method and all was well while under pressure from the fuel tank.  I ran it until it was warm (at least until what I thought was warm) idle with some rev-ups for about 5 mins.  and then the rpm sticking began.  I thought first that it was the idle adjustment.  I turned it down, but when it is stuck in the 4000 rpm range the idle doesn't adjust anything.  When it finally comes down from there it decides to idle around 1200 rpm.  I did notive a little fuel leakage into the air box after running it and the oil dipstick smells like fuel.  I have not really checkd for air leaks yet, but I will now.  I will also check the mixture screws and make sure they are at 2 turns out.

thanks
Alex

[Afzzr12]

I checked the idle mixture screws and one was out about 4-5 turns and the other does not exist.  I mean the left side carb, looking at the bars from the seat, does not have one.  It was either removed or fell out for some reason.  The guy I bought it from is a lying sack of s$#t.  He said he had the suzuki dealer downtown go through them.  i don't think a decent dealer would miss some thing like that.  I have heard of some serious mess ups from dealers.  But, not installing a idle screw come one. 

I guess what I have decided to do is pull the carbs and completely go through them myself.  Adjust float height and clean all the holes.  Double check all the jet numbers and find out where I can get a idle air mixture screw at.  If you guys can think of anything else let me know.

Oh yeah, I did adjust the one screw I have to 2 turns out.  I hven't started it yet though.  I don't want to because the oil smell badly of gas.  So I'm going to do the adjustment and an oil chnge before I fire it up again.  I think the right side carb is leaking fuel into the cylinder and the air box.  Not a good thing.

Thanks
Alex

[Toledo Jim]

There is only one idle adjustment screw total, not one for each carb.

Or were you talking about the air/fuel mixture screw?

I'm confused. 

[Afzzr12]

I mean the air fuel mixture screw sorry for the wrong term.  I seem to do that from time to time.   

[Afzzr12]

Well I adjusted the flost height on the right carb and all is better there.  I still have to get a mixture screw for the left. But after start up I am getting a backfire out of the right carb.  I have the mixture screw turned out 2 turns.  Why would the right side still be backfiring and the left side runs fine.  I just don't get it.  I guess i can't really diagnose it until I get teh other mixture screw in there. 

[Toledo Jim]

Well I adjusted the flost height on the right carb and all is better there.  I still have to get a mixture screw for the left. But after start up I am getting a backfire out of the right carb.  I have the mixture screw turned out 2 turns.  Why would the right side still be backfiring and the left side runs fine.  I just don't get it.  I guess i can't really diagnose it until I get teh other mixture screw in there. 

What I don't understand is how the left side is running fine with the mixture screw missing. 

How about it carb experts?

[Afzzr12]

Thats what I'm not understanding too.  You think the left side would be spitting and coughing just as bad as the right is.  It has gotten me all confused!!  The plugs look about the same color too.  I have even checked the valves and they are all in spec.  Man, I wish I knew more about carbs right about now.