Hello! I've been looking around for similar projects like mine but found none. I'm sitting on a WR450f 2004 which I bought two years ago, but only ridden for about 10h tops. Now I'm taking some of it apart, to check valves and carb. Found the valves too tight so fixing that. What is the cause of the valves getting too tight? I've got NO clue of the condition of the piston, which I should check - are there any symptoms of a worn piston? How does a worn cam chain look like? To me it looks fine. If I were to replace the whole package; piston, cam chain, could I drive this bike without worrying too much about it blowing up? The bike has run 20.000km. When I bought it, it started fine, great power, but got no info about piston, valves etc. I'm not planning on pushing this bike to the limits all day long. Mostly dirt roads and maybe sumo it in the near future. What would you do? I'm not a pro at this, yet, as you can see.