'97 CR250 idles too high

[XphilX]

I have a 97 CR250 that I just rebuilt for a second time (if any of you remember my last post).
Upon starting it for the first time, I almost had a heart attack. The bike wanted to rev to the moon. I quickly killed it and turned the choke knob all the way out. Started it again and it idles too high. Something along the lines of 1/10th to 1/8th throttle. I can't turn the idle down any more and I'm sure there are no vacuum leaks.
What do I do?

 

[Coolector]

Pull the carb and check to see he slide is sitting on the bottom of the carb with the idle screw out. It may be just a cable problem or something

 

[mriengr]

HI,
I owned a 97 CR250 until the middle of last year. Great engine and had the same issue after a rebuild. Found out that the crankcase gasket went bad on the flywheel side. The engine revved until I thought the thing was going to explode. Try replacing this as the engine will draw air from this area as the ignition cover on this model does not seal well.

Also the reason that this seal typically goes bad is when you crank bearing have aged to being out of tolerance. Have you replaced the bearings and rebuilt the crank since the bike was new???

 

[XphilX]

some more info

-always ran 40:1 before and switched to 32:1 for break in
-the air is pretty cold still around here
-i turned the pilot all the way in and the bike almost idled right but the choke knob is still turned all the way out

am i simply too lean?
do i need to go up in size on the pilot? or will this go away with warmer weather and some 40:1?

 

[mriengr]

Start and run the bike until it is warmed up. Afer warming it up turn off the gas and the motor should die from fuel starvation. If it continues to run and idle higher you have an air leak. The CR that I owned surged as well and the crank gasket is the problem that I found. If you would like to discuss it further call my engine builder.
www.eric-gorr.com He has great rates on repair work and did a kick butt porting job on my CR250. Made it a much friendlier bike to ride while lightning fast.

Hope this helps