.040
the gap for a Harley plug on a 88c.i. is 30
.040 or 40 thousandths
.040"
Use a dime to gap the plug. If u haven't got a dime use two nickles
.037"-.043" using any spark plug gap gauge. I have a 93 heritage softail classic and that is what is recommended.
.40
.040, or 40 thousandths
When changing the spark plugs on any vehicle, the person must leave the right gap size. The 1999 Harley Softail has a spark plug gap size of .040 inches.
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"
.038" to .043"
.040 is rcommended gap .040