The powervalve is not the only reason I want a newer bike. I want a newer bike that doens't have many mods on it so I know what all has been done. This 90 yz 250 has so many problems that I find. The person i bought it from didn't believe in warming it up at all. As soon as he started it, he would take it down the highway at full throttle. Then he wonders why it seized twice. He used a vw brake hose for the back brake, which didn't have the same fittings, so he welded them together. The bike has a much nicer life now that I have it.!!
I also have an 1982 yz250, and that is a very nice running bike. I bought a new spark plug for it when I first got it, and i used it for a couple years. Then I got the 1990 yz which had a terrible plug in it, so i switched them, and the plug fouled after a few rides.
when i turn the engine over, the arm moves only slightly,