just bought this bike and i was changing the oil in the gear box on the rear wheel and now the bike will not move. it starts and shifes gear but i give it gas and it does not move .when i drained out the oil only a little bit of oil came out this also is true when i drained the motor oil. but right after i changed that oil i did ride it around the block and noticed that there was a lot ofslipping from the gear box so i parked it anddrained the gear box oil thinking i had to much oil in the box and then tryied it again and then it did not move any more please help thanks.