I have an 03 rm 125, and originally the bike was set up from the factory with the idle screw all the way out so the slide can close all the way so it wont idle, and you have to keep revving it. Can i turn this screw a little bit in to make it idle. Will letting the bike idle cause a lot of spark plug fouling?
You can turn in the idle screw in to make it idle without any problem. They come shipped that way for racing because the bike is supposed to slow down for corners better without any idle. But for trails/casual riding and idle is usually better.