Dec 19, 2007
Ok I have to confess, I do have some knowledge on technical issues concerning 2 stroke engines but I'm very illeterite when it comes to carburetors. I have an 03 rm 250 and I was wondering what the little screw with a spring on it is. Its beside the choke on the carburetor. I have been told its air/fuel ratio and I've also been told its idle. Can someone please tell me what it is. I do not have a manual for the bike yet or I would look there. Thanks.


Jan 9, 2005
There should be two screws on the left side. One is larger, that is the idle screw. the very small one that is almost flush with the carb body is the air screw.

The air screw should be around 1.5 turns out,(counter clockwise) in the standard setting. Turn it in being careful not to tighten to tight, that will damage your carb. Assuming that your bike is jetted properly you can fine tune your throttle response by turning the idle up a bit faster than normal and adjusting your air screw between .75 and 2.5 turns full the seated position to find your highest idle. Once that is done you need to re set the idle with the idle screw.

2-Strokes 4-ever

Feb 9, 2005
Get an owner's manual, Suzuki has real good ones. The 03 RM is a real nice bike w/ a good motor, but getting the jetting dialed in is a nightmare. Learn the carb.....you'll be inside it a few times to get the best out of the motor. If everything in there (the carb) is stock, it'll need tuning. Getting it jetted right will make it run MUCH better.

Welcome to DRN

No trolls, no cliques, no spam & newb friendly. Do it.

Top Bottom