Best Way to Set Airscrew?

[Cleric]

Hey guys my carb isnt running too well and was wondering what the best way or how to tell when the air screw is in the right position. Any one got any good tips on where i should set it at?


thanks for helping me out

Cleric

 

[Joeschmo]

tighten it so its not over tight but you can feel it tighting up and go 1 and 1/4 or 1/2

 

[KX02]

Warm the bike up and get it to a steady idle. Turn the airscrew in until the bike almost stalls and then slowly back the screw out, counterclockwise. Keep turning it out and the idle should start to get faster and faster, 2.5 turns should be the max you can adjust it out. When you get to the point where it idles fastest, determine how many turns out it is. If it is set more than 2 turns you probably need a smaller pilot jet, less than 1 turn you need a bigger pilot jet.

 

[Cleric]

ok thanks i will do that. But if i determine if i need a smaller or bigger jet and install it where should i set the screw so it is perfect or is it just user preference?

Thanks for your help

 

[KX02]

Ideally you would want it around 1.5 turns out so you can adjust it in both directions.

 

[Cleric]

thanks sounds good

thanks for your help

 

[CaptainObvious]

I agree that ideally you want your airscrew about 1 1/2 turns out. And I also agree that you should adjust it with a warm engine for the lowest opening that will allow maximum RPM. However, that is just a starting point. The airscrew should be further adjusted to provide the best throttle response.

This is determined by riding the bike for a few minutes with closed throttle to 1/3 throttle roll-ons. Fine tune the airscrew for the best throttle response in this regime.

 

[Cleric]

ok well i went out and did the air screw technique but my airscrew didnt stop at 2.5 it almost seemed like i could take the whole thing out but i stoped at 3 and brought it back to 1.5.

Can my airscrew come out more than usual or what is going on?

thanks

 

[kelsorat]

No do not unscrew the airscrew any more. If the airscrew falls out, you risk contamination of your carb. Then you need to thoroughly clean the airscrew and decide whether or not you feel confident enough that no dirt/dust could have entered your spotlessy cleaned bike and workspace.
Follow KX02's advice, and write down your final carb settings for that date,elevation,and temp. This info will save you alot of headache in the future. Out west we ride all year long, so your 2 stroke should be jetted cleanly Jan-Dec. And that requires frequent jetting adjustments based on altitude of riding spot and temp.

 

[Cleric]

ok thanks for your advice.

If my plug is dark black what do you think i need as far as jetting?

thanks

 

[snb73]

Cleric,

These should help you some.

Steve

http://www.eric-gorr.com/twostktech/carbtuning.html

http://justkdx.dirtrider.net/carbtuning.html

Heres a good baseline to start from:
http://www.mx-stuff.com/jettingspecs.htm