Valve adjustment Procedure.

Remove the 2 left side allen plugs one is used to rotate the motor when doing 
valve adjustments. The other is to stop turning the motor in the right place.

Remove both valve covers on the front head.
Rotate the motor CCW to where the Front intake valves are just closing. 
Then with a flashlight, looking into the inspection hole, rotate the 
engine CCW until the Front timing mark is in the center of the hole. 
Adjust both sets of valve to spec... .003 to .005 inches.

Remove both valve covers on the rear head.
Rotate the motor CCW to where the Rear intake valves are just closing. 
Then with a flashlight, looking into the inspection hole, rotate the 
engine CCW until the Rear timing mark is in the center of the hole. 
Adjust both sets of valves to spec... .003 to .005 inches.