Hi, am new to this forum, find lots of good info here. I have a problem with my 03 yz450 that I bought used 3 weeks ago. The last owner just replaced the piston and gaskets just before I bought it. I have a problem with the bike loosing coolant nearly everytime I ride. It seems to go out the overflow tube from my radiator. I have tried switching rad cap with a friend that have the same cap and nothing changed. The amout of coolant missing seems to be greater every time I use the bike and refill it. It has 6 hours on it after rebuild and is ridden at dirtroads, and at trails in the forest. Can this be a leak headgasket? Any tips about what to look for?