[Goat Blower]

Check your base timing, set it at 5 degrees BTDC for starters. Also check the alignment of your timing marks. Your timing mark on the crank pulley should be at TDC when both cam gear timing marks are lined up. You should be able to run a straightedge along the lines through the center of the bolts and have the crank pulley mark lined up as well. If not, the belt has skipped a tooth, which sounds like your problem.