HELP!!!!!!!!!!!!!! Can't Set Idle

[UngerOne]

I just recently purchased a 1993 GSF400 and it runs really well except for midrange and it will not idle at all.  I have followed the service manuals recommended method for setting the idle, but have had no success.  Any help would be great!

[gsxr400 racer]

where is the idle screw 

[UngerOne]

According to the service manual, the idle is set with the Throttle stop screw which is on the left side.  But when I turn it to increase the idle and then hit the throttle it doesn't back off very fast at all.  Which makes riding difficult cause it wants to pop a wheelie in every gear.  The service manual does not mention any other way of setting the idle.

[gsxr400 racer]

idle screw are in the middle of the carbs between 2-3 usually a big screw or a knob with a braided wire that goes to the middle of the carbs. sounds also like you may need a carb sink

[UngerOne]

Ok, it looks as if what the service manual is calling the throttle stop is the idle screw.  The big knob on the left goes under the carbs and then bends up and goes between the two middle carbs.  When I turn it the idle does go up but when I hit the throttle it revs up but comes back down very slowly.  What is the best way to tell if the carbs need to be sinked? One other thing, I have noticed that if I put the choke on just a bit I can keep the idle up around 1400/1500 but it will not stay constant, sometimes it will jump up to 2000 for a bit and come back down.

[gsxr400 racer]

you could have a dry throttle cable, a frayed throttle cable, a air leak, carbs out of sync. dont mess with the choke it will just foul out the plugs by some new plugs and it might idle fine...

[PitterB4]

OK... Keeping in mind that I'm not all that bright - couldn't the air screws be really lean?  Have they been messed with (are the plugs drilled out)?  Have you recently messed with them?  Just a thought...

[UngerOne]

I do know that the guy I bought it from said that when he got it it had been sitting for like five years and he had to remove the carbs and clean them.  I am not sure if the air screws have been messed with at all but I do know that the plugs are brand new.  Would it be best if I just took it to the shop and let a pro check it out?  I have worked on and rebuilt many car engines and my dirt bike but this is the first street bike I have had that has carb problems and I don't want to screw anything up.

[PitterB4]

Sorry man...  by plugs, I meant the little brass 'plugs' that cover the air screws.  They're drilled out to get at the air screws when tuning the carbs.  If they are exposed (meaning someone has messed with them), screw them in until lightly seated while counting how many revolutions on each.  Make a note of that.  Then I'd back them out about 2.5 turns and see if that makes any difference. 

[UngerOne]

Thanks for the advice man, I will check the plugs first thing tomorrow and let you know.  I really appreciate your help on this matter.