I'm new to the world of 4 stroke dirt bikes and I'm just wondering why would someone want a 4 stroke over a 2 stroke? Other than the fact you don't need to always mix oil and deal with the smoke what other reasons are there? I just bought a used 2005 YZ 450F and it seems like there's a boatload more maintenance on it compared to the older 2 strokes I've had in years past. The more I read about all the 4 stroke issues the more I wonder if I made the right choice. As it is right now I can't get this thing to run right after rebuilding the carb so now it looks like I may need to check the valves for proper adjustment. The bike doesn't have many miles on it but it looks like that's the next thing to check since I can only keep the bike running with the choke on.