2008 YZ450F I recently had to replace some gears and one shaft in the transmission and I have rode it about three times since with out any problems but I went to load it in the truck today and there is a light knock in the transmission while rolling the bike in nuetral. I put it on a stand and took off the chain and I can rotate the sproket by hand and it turns smoothly but at the same spot everytime it has a slight knock. It has the same sound like if you rotated the sproket back and forth and you can hear the teeth between the gears mating. Any ideas ???