My shop manual states spark plug torque is
18.4 ft-lbs. Wow!??

I never use a torque wrench for plug changes,
just common sense.
But thot I’d ck the manual just fwiw.

18.4 ft-lbs seems WAAAAY to much. What
feels right is only around 8-9 ft-lbs imo. Ya
only need to crush the washer plus a little.
Or go by the rotation graph on the plug box.

I think if anyone torqued to shop manual
spec they’re asking for trouble.

Any comments...,
Yamaha.., Jerry??