The correct answer is between 38 and 40 (esp if its an '01) No less than 40 and no more than 45.
40 to 45. 40 is common.
Plug gap for the Sportster 883 or 1200 should be .040
.028 to .035 according to spark plug brand.
.04
.038-.042
.040".
.040
.40mm is the recommended gap
with a left-handed spark plug wench...hehe, then you gotta putt'em in with a right-handed spark plug wench
HD 6R12
Manual says .038 - .043
40 to 45. 40 is common.