Have you taken off yet? If set it to top dead center. To set the timing you should turn the No.1 piston to TDC, check the cam to where both valves on No.1 are close. The timing mark on the sproket should now be in line with the mark on the cilinder head. Remove chain without any major disturbance to sprockets. Check No. 1 still on TDC. Cam mark right. Fit the new chain.
After fitting turn the engine a few times by hand to make sure there's not a valve pushing/hitting against a piston. Recheck marks.
January, 16, 2012 AT 7:07 AM
Oops. Word missing. If NO, set to top dead center before removing chain.