Air Screw on 450

My bike is running great and my 04' 450 is my first four stroke. I do all of the right maintanence and have owned the bike for a year now. From the time that I picked the bike up from the dealership I have not had to adjust anything. What I want to know is when you should adjust the airscrew if needed. Can you tell by how the bike idles? Just looking for some input thanx. :)

Your Keihin airscrew is in fact a fuelscrew since it sits between the cylinder and carb slide (= on front of the slide) on the bottom of the carb. Opening it up counterclockwise gives it more fuel. You can open it up half a turn for every winter, because colder air contains more oxygen which may make it run too lean without more fuel.

When the weather is very warm or humid you could close the fuel screw a bit, but I would not go leaner at all if the bike has run well so far. A bit too much fuel is never bad. If you want to do something, try opening up 1/4 turn and see if it runs even better now. If it runs like before, don't go back.

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