For Three years my buddy has rode the yz450 without as much as a squawk out of his bike. He has never had to reshim or do any major repair. Last year he crossed over to the cr450. Having heard the rumors about the valves, he was very religious in the maintenance of the Honda. He also thought allot of the Hondas premature valve problems was due to dirt falling off of the filter into the boot upon removal of the air filter. So every time he cleaned the air filter he also removed the boot to make sure it was completely cleaned. Long story short he had to replace the valves and head after just one season. He started to inquire to his other cr buddies and discovered that they all couldn’t get more than one season out of their head and valves. My buddy still loves his Honda but has come to terms that the cost to ride the magnificent beast just costs more. So am I Honda bashing? No, I believe the Honda is a great bike that is a force to reckoned with, but I don’t like the idea of losing riding time due to the bike being in the shop and also having my wallet eight hundred dollars lighter every year. My hat goes off to the engineers at Yamaha for allowing me to use my money on fun stuff instead of major repairs.