Sorry to be nearly a repeat of the last post, guys, but I need your advice, and my situation is quite a bit different from "Seb's." I'm seriously considering a CR450, and semi-seriously considering a YZ450. The key limiter is the lousy support at the Lancaster, CA Yamaha dealership, and the opposite at the Lancaster Honda dealership a few blocks away ("Will" in particular is a class act). A few questions: 1. I'd greatly appreciate an idea of maintenance items and costs, and how frequently each is needed. Valves? Oil? Top end rebuilds? Gearboxes? Cam chains and related hardware? 2. Any problems to report? Four speed trans working out okay? 3. Is the 450 really that much of an improvement over the YZ400? I have been a CR500 rider for many years, with a 1997 bike being my latest. The motor was fully worked by Boyesen Engineering, and it is pretty much unbeatable in a drag race, if traction is good. It's also the hardest bike to ride MX that I know of, and its turning is not in the league of the YZ400s I've ridden. However, as you know, the CR500 is rock reliable and really fun to ride. Thanks in advance for your input!