01 CR 250 won't idle even with Idle screw all the way in!

[Rocky Mountain Rid3r]

I recently bought my self a new bike , 2001 Cr 250, and it wont really idle at all. It will idle though when its cold like when i first start it but once its warmed up it doesn't seem to want to idle. I'm thinking maybe it needs new reeds? Any help would be appreciated. Also the top end is in good shape.

 

[TheMuffinMan]

A stuck or malfunctioning choke would cause that. Could be a bad stator as well, sometimes they will work fine when the engine is cold but when they get warm they start to lose output, weakening the spark. Also, check your air screw adjustment, it should be between 1-2 turns out. A lot of guys have no clue what it's for, assume its just another screw holding something together, and tighten it right up closed. This will make the bike run way too rich from closed to 1/4 throttle, causing symptoms like yours. The rich jetting acts like a choke, helping with cold starts and warm up and then stalling the bike out once it gets hot.

 

[Rocky Mountain Rid3r]

Alright thanks dude! I'm pretty sure it isn't the choke as I've cleaned the crab top to bottom and made sure it was all working but I'll give the air screw a look. It didoes smoke or anything a whole lot so I think its jetted fairly decent.

 

[dezmitchell]

If i were you i would MAKE SURE its jetted properly find out what you need and check it ....Yes a choke sticking will do that. The air screw can compensate for some pretty severe pilot jet issues the air screw should be between 1.25-2 turns out.

The fuel/air mixture will be leaner if the air screw is screwed out and richer if screwed in - think of it as a 'leak' in the pilot metering circuit. When screwed out it allows more air into the circuit and therefore less fuel and it will effect pretty much your hole throttle range.

 

[Mr Husaberg]

Not a lot of data to work with to jump right to reeds but pulling them apart to check them is never a bad idea. Pull the carb apart blow all the jets with compressed air and compare with stock setting. At our altitude one leaner on the pilot and main never hurts. With stock jetting the bikes are set up for sea level and will foul a plug very quickly at idle. If you start it and ride slow til it's warm you can make a plug last with stock jetting. But it is too rich for letting it idle with the stock pilot.

 

[Alex Shiskin]

Check your jets and your needle. Download a manual and set your screws to the stock setting. I know on my yz the air srew is 2.5 turns out.