Hi. I have a question. I just bought a 85 GS 5-speed with the original carb and no mods yet, and am having problems with the engine idle. It likes to say at about 1500 to 2000 rpm. When it is at 2000, I can blip the gas and it will usually drop to about 1500. Once in a blue moon it will drop to about 1000-1200. I was wondering if anyone else had this problem and how do I go about fixing it. Any help would be appreciated.

Chris

 

Check the rats nest for vacuum leaks (or better yet remove it *shameless plug*) and try adjusting the idle setting screw (from the drivers' side of the engine bay, it's straight ahead about 5 inches from the firewall at the base of the carb). A good default adjustment is to screw it in flush then back it out 1 and a quarter turns.

 

There is also an idle mixture screw directly below the idle speed adjustment screw that will allow you to change the 'quality' of the idle. What I've found is that changing one will alter both speed and quality of the idle, then changing the other will alter both speed and quality of idle... what this means is that you're going back and forth making slight adjustments to both screws until it idles the way you want it to.

It takes some time, but once you get close, you can start making 1/8 turn adjustments and get it dialed in very well. This is as long as your carb is in good shape for performance and you don't have any air or fuel leaks. HTH,