Dirt bikes - The motor runs backwards.

I have a 2001 yz80 dirtbike I replaced the crankshaft in it. Now the motor runs backwards.
Can anybody please help me with this?

I have a 2001 yz80 dirtbike I replaced the crankshaft in it. Now the motor runs backwards.
Can anybody please help me with this?

I've only seen that once in 30 years. Unless you assembled the motor wrong it can only happen when the timing is way off.
Check the stator position. If that's correct you will need to verify TDC and the timing marks by using a dial indicator. If the crankshaft is twisted, it would throw the timing off also. If your TDC mark doesn't match what your dial indicator says then you know the crank is the wrong one or is twisted on the pin.
I can't give you any detailed specifics, but it's just not that kind of problem.