I just picked up a 2001 yz250 yesterday. It cranks first kick cold with no choke and sounds great. But when I ride it, something isn't quite right. It will rev all day in neutral, and in first gear, but when I get in second and up it doesn't want to rev out all the way. It sounds like it's hitting a rev limiter around 3/4 throttle and it just doesn't have that "scary fast" power band that everyone has warned me about. If I ease into it in second it will hit about half the time. Here's what I've done so far: case oil change, spark plug cap, spark plug, air filter, new gas (he was running 50:1, I changed over to between 32:1 and 40:1). The previous owner said it "may" have a flywheel weight on it, which I thought would tame the transition some but not kill the top end. Also it has a full pro circuit pipe on it and he said he thinks it hasn't been jetted. I was just wondering if anyone else has run into this problem and has a quick fix solution or any ideas. When I checked the old plug it seemed rich, but when I swapped plugs it didn't look as bad so I'm not sure if it is or not. I haven't yet looked at the jets to see what's in it, like I said I've only had the bike 24 hours. I didn't know if jetting would kill the top end or not, I haven't really ever messed with two bangers and I've never put a pipe on a bike so jetting was never an issue for me. Any help is appreciated!