Dirt Bike Help!!!

[ITSSLOW]

I got my uncles CR230F and DRZ125 tuned up and ready to hit the trails so I move on the to the P.I.T.A. KX65. The kickstarted was locked up so I try to unlock the motor by putting it in gear and rocking it back and forth. Normally you would have very little resistance doing so but I had to work my ass off to spin the tire. I pulled off the pipe and carb/reed valve and look at the piston while spinning the rear tire and its not even moving, even though the front sprocket is. I pulled off the side cover and using a socket/ratchet I manually turned over the magnito and the piston came free. Watching the piston as you turn it you have very little resistant (only a 65cc with no spark plug in head) but as soon as you get to BDC it gets hard and the next like 10degrees and it starts to go back up are a complete P.I.T.A. then it gets past there and moves just fine until you get back to BDC. Any ideas? That last test was with the bike in nuetral..... Once you get it past BDC it also kicks over just fine.