I'm resurrecting an '04 YZ450 from deep storage. Still has original tires with the little nubbies and paint on em, so it is really in great shape. Probably still needs a break in... I just replaced the coolant, oil+filter, plug, and pulled the carb. There was a lot of gunk in the carb obstructing the jets but I soaked it and blasted it with carbclean. I could only get the bike to start with the hotstart engaged. And once its running, it really wants to die if you release the hotstart. So I rode the bike around with the hotstart pulled and it seemed to run fine. A couple quick yanks on the throttle and it was like setting off controlled explosions around my neighborhood, craazy bike. However, when I release the hotstart the thing drops in idle rpm (i have to twist the throttle or it stalls) and seems very rich, boggy. I'm riding at sealevel and ~45 degrees F in Seattle. Stock jetting in the carb. I didn't have the chance to blow compresed air in the carb, maybe that would help?