Idle Tuning

[Bahnstoermer]

Guys, I'm hoping this doesn't lead me down a path requiring me to learn the art of carb tuning but here goes...2002 or so Warrior.

I adjust the idle screw most times I ride since it seems to need it, based on temperature changes, etc.

The issue is that on start up the motor revs too high, so I adjust idle down. Then when warming up it revs down, so low in fact I have to raise it back up. The range is even more when outside air temps are low, that's when it revs up the most at start up. The range is too much to be tolerable, something must not be right. I don't really use the choke as it doesn't seem to make any difference.

It seems to me normal operation should be, pull choke to first or second detent when cold starting, then push in to maintain smooth idle upon warm up (like every other engine right?), but this isn't the case.

Motor as far as I know has stock internals. Stock carb, has a pipe and "ecu" upgrade if they're called that. Not sure about jetting situation, it was a hand me down sort of thing with many previous owners...

Input?

Much appreciated, I'm fixing things left and right from the previous owner(s) which is satisfying...

 

[CJCaldie]

im no pro at this but even when you pull the choke its still going to rev low. just let it sit there and warm up. when its ready to go the rpms will shoot up. push the choke back in and ride. cant remember off the top of my head but pretty sure when warmed up it should sit at 1400-1500. when mine is cold it sometimes runs at like 700-800. every once and a while i have to tap the throttle to keep it going. always tune a warmed up bike. i wouldn't be too concerned about how it runs cold if it runs fine warmed up. my buddy just bought a bran new 350 grizzly and even it likes to put up a fight sometimes running cold

 

['00 WO-YA!]

@cjcaldie, A.D. though it's a stock bike you can't use it as the standard....believe it or not. The thing is that the factory sets neatly every bike, chainsaw,.lawn mower, weed eater, etc up lean now days. They're concerned about keeping emissions in check so that uncle Sam is happy.. I will give you this though, you ate right, you never try to tune a cold engine. Tune it happy when it's warm and work with it till it's warm when it's cold. I never push a cold engine, especially if ambient temp is low. I let them start and hold consistent low revs until our begins to warm, then I play with the throttle some. To be honest I don't run an engine on choke long, I prefer to use it to get them going and let my thumb do the rest till warm.

 

[Bahnstoermer]

"when warmed up it should sit at 1400-1500. when mine is cold it sometimes runs at like 700-800...."

Mine does the opposite... revs high when cold, then calms down. But it revs TOO high cold... sounds like it's going to take off an aircraft carrier LOL, and as mentioned above, I do NOT want a cold engine revving high instantly, I want it to warm up gently.

 

[Gen1Pat]

Double check your intake manifold for any cracks. Sounds like it has a slight lean condition. How does it run otherwise?

 

[CJCaldie]

ok thanks for clearing that up WOYA. i didn't know that but makes sense. probably why i ended up richening my mixture screw a little. i actually rarely ever touch the choke here in AZ. if i have to its usually to start it up too. ive let it warm up all the way with the choke when it was in the 40s in the mountains. kinda think its cool how they let you know when theyre ready.

as for OP i didn't catch that. someone better than me would have to chime in on that. since im commenting here though i might guess that imfamous cracked boot problem people talk a lot about.

 

[Bahnstoermer]

I agree it would suggest lean... A crack of sorts in the intake path somewhere would seem a good idea to look for. Otherwise it hauls the mail!