New to pit bikes. Just Bought a used 2008 X4R, 150. Noticed that the front sprocket would wiggle side to side. Did not think that this was right. Added a washer between the sprocket and mounting bolts. Has anyone else had this on their bike? Also the bike had a oil leak. The previous owner said that he did not lok tight any of the bolts so I did. Still had a leak. Pulled the motor and found a crack on the engin right behind the front sprocket and right on the engin mounting bolt hole. can this be welded or J.B. Weld?