Does idle screw affect performance?

[CR-For-Ever]

Hey all,

I'v been working on my bikes carb..and I'm curious, How does the idle screw affect performance?

I relize that if you turn it you can decrease/increase idle of the bike but how should it be set? And if I have the bike idling fast will that have anything to do with the bikes performance?

Just curious, thx.

 

[Jaybird]

The idle screw opens up the carb witout changing the mixture.
You need to have your Air Screw set close to what your manual states as a baseline. You may need to tweek in the idle screw to maybe keep the bike from just stalling.
Good throttle response in that condition would mean you are close.

 

[CR-For-Ever]

Ok...

So what you're saying is set my air screw say at 2 turns out then see how the bike idles? And the bike should idle like it's always about to die?( Stall)

Cause I'm a bit confused
Thx.

 

[whyzee]

Originally posted by CR-For-Ever
How does the idle screw affect performance?

It won't.
As Jay stated, set your air screw to a factory setting, then adjust the idle screw for the desired idle RPM. Once you have the desired idle speed, adjust your air screw for 0 to 1/4 throttle response, more than three turns out...get yourself a leaner pilot jet.
The idle screw is nothing more than a stop for the slide.
Good luck,

 

[CR-For-Ever]

Ok that sounds great!
Just one more thing what should my idle be set at? on a 125 I'v herd it should be really slow do I want it to be set really slow like about to die or medium or a fast idle?

thx.

 

[James]

I always hear that you are supposed to set the idle screw on a two storke where it doesn't idle for more than a second or two.

But then again, I am always seeing the racers crash, collect themselves, pick the bike up, and it is still running? Seems like they must have them set to idle?

I'm confused.

 

[CR-For-Ever]

Sounds good.

I'll set the idle screw so that the motor dies after maybe 2-5 seconds...

As always thanks for your help,
Later.

 

[a454elk]

CR, you can set your idle to last until you want it too, totally up to you. Yes, racers set theres like that because they don't really care about idling. If you have proper jetting, you can idle your bike no problem. Yes, idling for a long period of time may load up the 2 stroke. If you're a normal rider like most of us are, let your bike idle, it'll help if you trail ride along with MXing. Having an idle may decrease your compression braking but you probably won't notice the difference. Good luck

 

[MrLuckey]

Or in some people's case (4 strokers who haven't done the BK Mod yet) they will set the idle high enough to get them past the 'off idle stumble' problem :p