I've always adjusted the valves with the engine off. Has anyone done so with the engine running? As I understand it, you loosen until clicking .Then down to end clicking. How much more down after clicking stops? 1/4 turn, 1/2 turn, one complete?

 

IIRC, the manual states one turn once the pushrod to rocker arm clearance has been removed. The same should hold true for adjusting the valves with the engine running as the purpose is to center the lifter travel. You will need the oil stoppers that click on each rocker arm to keep it from spraying oil all over you. Since the rear of the engine is lower than the front, it helps if you have the rear end raised up a little bit keep the oil from pooling at the rear of the engine and then running over the side.