What kind of design does the ZC engine use to move it's valves? I'm trying to adjust the valves on a ZC, do I just undo the nut around the adjusting screw? It seems to be on tight and I don't want to break anything.
yes, that is the lock nut. loosen that, then you use a flat head to adjust the clearance, then when it is within spec, you have to hold the adjust screw with the flat head and tighten down the lock nut.