well my rings locked up on my awhile back abou a month ago. i took it all apart.it had scuffed the cylinder adn the exaust brigdes were cracked. i sent it in to get welded up and replated. it turns out the had to bore it out so i gained another 5cc. i got it all back about 2 weeks later and i put the powervalves in how i thought i should.i put it all back together and got it broke in. i got it in the power band and it was gutless.i couldn't figure it out.finally i came to the conclusion that my power valves were in there wrong.so i tore it all back down again. turns out that when you work on it and put the valves in the right is on the right but on the 250 kdx you turn the cylinder overso the valves heads are on the bottom and so they are on the opposite sides. so i switched them so they were right and put it all back together again. once i did that it had a awsome powerband thanks to new power valves which are $55 a pop a piece.(ouuuch) anyways today i clicked it up to 5th gear which is top for a 250 adn cracked it and wiht a little arm pull the front end sailed above the ground. i went for a 1/4 mile and set it back down. i had it pinned all the way and it just carried all the way wiht no let off or anything!that was the best wheelie i have ever done and it was in 5TH GEAR!:p but anywyas i would liek to thank all that helped me in my rebuild form this site. And keep on riding!