Ok so I have a 2003 400 ex. Last weekend went out riding everything was fine and dandy I loaded onto trailer to take home. Got home and unloaded to put in garage and it acted like it wouldn't go into gear. I push down on shifter and it "clicks" into gear but doesnt seem to actually engage. Now if I let out on the clutch in first gear and give it a decent amount of throttle it barely wants to move forward. It seems to move thru all gears but actually doesn't engage in anything but neutral. Any pointers??

 

Take a good long look at a part fiche related to your shift drum/forks...sometimes the pin and or springs can come off...so your gear lever moves, but it's not moving the drum to shift the gears...