KDXRIDER.NET

Hi all.
First off.....sorry if this is a stupid question or not.....
Just wondering with the air screw, do most people turn in or out during cold weather?
Just going riding up north next month for the first time and know colder weather will be upon us.
03 220 is jetted pretty darn close for the normal type of riding I do in late spring/summer/ealy fall (great sticky btw) but not sure about later fall.
Just wondering if the air screw will be enough to see me through. Really won't have time for plug chop etc.

Thanks in advance

The air screw is just a metered air bleed into the carb. Turning it in (CW) richens the mixture, and turning it out (CCW) leans it. As the air density increases (lower elevation or colder air) you may have to turn the screw in slightly to compensate.

Theres a catch though.

The air screw operates in the idle (pilot) circuit so it only fine tunes the first 1/8-1/4 of the throttle opening it. After that, it's the needle (til about 3/4 throttle) then the main jet that controls the mixture. The bleed screw will have little to no effect in those ranges. you may have to tune the midrange further by raising the needle (richening the mixture) and/or go with a larger jet. The advantage here is that you can get to the needle and the main jet without removing the carb.

I have been reading plugs for decades and I have a tool that allows me to magnify and see into the the plug to the ceramic without chopping up a perfectly good plug. Jegs or Summit has them and in the long run its cheaper than cutting up dozens of plugs (I have 7 bikes and 3 drag cars......). Might be worth looking into......

If you hate tuning the carb, run it a little on the rich side and just accept the slight loss in performance. A lean mixture (detonation) will KILL your motor.....

Another idea just came to me. If you arent talking huge changes in environmental factors, you could also help the situation by changing your premix ratio slightly, say 35:1 instead of 40:1, that way, you get more fuel (richer mixture) to help. Yes, it's a bandaid, but it may help. Note that if you are already running a fairly rich (more gas, less oil) ratio, say 32:1, be careful you don't want to kill your bearings. I hear thats bad too.....

Pete

Thanks guys for the reply.
Pete. Good info. Thanks. Through the summer (20-30C) bike run awesome and plug always looked great (mocha color on porcelin). I read the the sticky/post and went by that and after a few adjustments, I got it just about right. Great note/advice. This is the first time riding this late into the season for me as kids sports usually start to take over. However, off with the boys for some riding a little farther north and was just concerned about starting off cool in the morning and getting somewhat warmer in the afternoon. Will also try changing mix too. usually running 40:1 and don't mind just a little spooge that is produced (minimal)
Thanks again