The way I do mine ... easiest with plugs out, on the cam chain tensioner, undo the lock nut, loosen the pinch bolt that holds the plunger and rotate the motor forward until you feel the plunger is in as far as it will go, stop rotating, tighten the pinch bolt and the locknut. Job done. Don't put pressure on the plunger by pushing it in.
Have you got a copy of the owner's manual? They are VERY useful for this sort of thing.