Feb 25, 2001
394
1
Over the last year my CR250 has been running considerably worse. During deceleration after letting off the throttle the bike will make a very erratic chug chug type of idling down . Along with some sort of rattle type knock when decelerating . Always use VP C12 with full synthetic 32:1 fuel mix.

Spark plug is black & dry with no buildup. Very clean exhaust does not smoke much and no spooge on the fender near the silencer.....burns very clean for a 2-stroke .

Throttle has lagging response from idle-1/4 throttle. From the needle to the main it runs beautiful, just low throttle hesitation. Currently has 37.5 pilot jet. What gets me is the air screw when I checked it was 3-4 turns out!! Does that mean I need to go to a higher or lower pilot? I know my air screw should be no more then 1.5-2 turns out. I tried 2 turns out to see what it does and the bikes RPM's stay pretty high and never return back to idle. It takes 3-4 turns out on the air screw to get the idle to settle back down. Bike has a pro circuit pipe & silencer, I had referenced their website for jetting suggestions and for my altitude they suggest #35-37.5 pilot & AS 1.5 turns out.

Am I experiencing to lean of a pilot jet & air screw setting?

Also I noticed when starting the bike cold it will only start it you blip the throttle while the choke is on. It does start very quick when you blip the throttle on choke. It never used to only start with throttle.
 
Feb 25, 2001
394
1
Fresh reeds as of maybe 1 hour of ride time and fresh spark plug. Haven't checked the crank seals....what symptoms would leaking crank seal create? I was assuming it would run really rich and have a ton of burnt smelling smoke if it was a crank seal? Which is does not smoke much at all.
 

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