Hey everyone. I'm thinking about ditching my 03 CRF450R and going for an 07. The big question is ... CRF ot YZ. Both bikes seem to do everything equally well. My biggest concern is maintenance, specifically valvetrain. Does the YZ require any less maintenance with it's smaller valves? Also, the bike will be set up for desert riding/racing (vet/C desert scrambles) so do the YZ's boil over less than the Hondas? My CRF sometimes boils over in deep sand or when out riding w/ the kids. Thanks.