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Making this post as future reference for people thinking about messing with the spark plug as this is an unknown value that I had to get by contacting NGK.
I got a NGK spark plug for my bike. Now I decided not to use a torque wrench because apparently it is more reliable to just tighten it based on turn radius.
With new crush gasket the spec is 1/4 of a turn. However I also thought that when the times comes to inspect the spark plug the radius could not be so high considering the gasket had been crushed (and I wouldn't replace the washer because ugh). So contacted NGK and the spec for tightening a spark plug with an already crushed gasket is 1/12 of a turn. So I guess now we know.
I know most of you do it by feel but it is good to have an actual value.
It is also a bit confusing that the honda manual recommends 16Nm torque when NGK recomends less for cast iron and aluminium cylinder heads. Allthough I suppose the honda torque might be the correct one considering they know what exact material the cylinder head is made of but also I doubt it is anything softer than aluminium so why is the torque so high?? Either way I think most just use NGK's torque value/radius value or just tighten it a bit after finger tight, I just thought this was quite interesting.
I got a NGK spark plug for my bike. Now I decided not to use a torque wrench because apparently it is more reliable to just tighten it based on turn radius.
With new crush gasket the spec is 1/4 of a turn. However I also thought that when the times comes to inspect the spark plug the radius could not be so high considering the gasket had been crushed (and I wouldn't replace the washer because ugh). So contacted NGK and the spec for tightening a spark plug with an already crushed gasket is 1/12 of a turn. So I guess now we know.
I know most of you do it by feel but it is good to have an actual value.
It is also a bit confusing that the honda manual recommends 16Nm torque when NGK recomends less for cast iron and aluminium cylinder heads. Allthough I suppose the honda torque might be the correct one considering they know what exact material the cylinder head is made of but also I doubt it is anything softer than aluminium so why is the torque so high?? Either way I think most just use NGK's torque value/radius value or just tighten it a bit after finger tight, I just thought this was quite interesting.
