I have the opportunity to pick up this bike for $1950. The owner bought it new and claims to have taken very good care of it and says the top end is fresh (1st one in five years of ownership). It was raced in the senior vet class at the local track so it sounds like the thing hasn't been too beaten up. I'm concerned about valve issues though. I've read that the 04 and 05 had problems in this department. I'm torn because it seems like such a good deal. What do you guys think? Also I'm coming from a two stroke background (01 YZ125) so any maintenance/riding tips would be appreciated in the switch over to 4T. Thanks