H-D brand: 3-4
Accel brand: 2401
Autolite brand: 76
Champion brand: J12YC
The suggested spark plug gap for a 1973 Harley Davidson is 0.040. It is the suggested gap for most of the spark plugs of that era.
.040"
40
The spark plug gap should be .040"
the gap for a Harley plug on a 88c.i. is 30
1.00 mm
.040
35
.040".
.040
HD 6R12
40