I know the adjusting screws have 4mm square head. I'm 99% sure the locknuts are 10mm. Not sure why you are asking about 12mm & 14mm? I use a socket (1/4" dr.) to snug up the locknuts, then recheck. Just take your time. Engine much easier to turn with one sparkplug removed from each cylinder. The 4mm wrench is available from Honda.