Hmmm, for a long time I've been dealing with erratic idling on my 94 KLX 250.

It wasn't like that when I first got it at 12500km, started about 1000km later. I shimed my valves as two where out of spec and the erratic idling continues. I checked the carb, adjusted the float, cleaned it, no change. I checked for a vacuum leak, but didn't seem to find any. I noticed the crankcase vent hose ends where stretched out so I got better clamps to ensure it was sealed properly.

When I ride, when I come to a stop most often the revs will stay at 2000-2200 and than after 20s-30s they'll drop to 1400 (where I want it). If I rev the motor the idle revs will climb to 2000 again and stay and drop. Sometimes it just revs at 2000 and doesn't drop at all. If I adjust the idle lower, than when the revs drop the motor stalls. My pilot is a 2 turns out, 40 pilot, but idle system seems very solid.

Any ideas welcomed. Thnx

 

perhaps trying some octane booster or mix in carby cleaner.
10 or 20 bucks

 

Been there. Pilot is too rich. Get a #38 (like I did) or go back to the stock #35.