k2bjarne,
I can relate to your problem. Sometime ago I rode a buddy's '99 KX250 and loved it, had to have one to replace my '99 CR250. I bought a '01 KX 250. Great power and handling that’s way better than the CR, IMO. However, the power delivery was nothing like the '99 KX.
After my airbox separated from the boot (you may want to check yours) and major dirt ingestion :o , I sent the top-end to Eric for some work. Since the cylinder needed re-plating anyway I asked for the 265 kit with Mo Better porting. What a difference, low end power that makes gear selection far less critical and linear power from bottom to top with hardly any hit. Much like a 500, with less power. I must say that it makes this bike very easy to ride and with the addition of a fly wheel weight (9 oz.), a great trail machine. :confused:
Good Luck,
Scott