sae 10w30 is good for 85 Degrees Far. to O Degrees Far. . But sae10w40 is good from O Degree and up - but any oil is better than no oil.
Being that the clutch is a wet clutch it runs with the motor...
This was a question my auto shop teacher asked my class back in 76, just what does the HD mean on a can (at that time, before bottles of oil) of oil. Got many different possible answers, Heavy Duty,...