I found it somewhat frustrating on the three HD-25’s I went
through to get the "coil shoe to magnet" clearance adjusted
even. I tried using two feeler gauges at once, one on each
end of the coil shoe. A normal feeling gauge blade is about
1/2" wide, and doesn’t fit the curvature of the gap
being measured, so I’d be just trying to catch the outside
of the gap. The gap at the center shoe that the coil is attached to
is harder to see yet.
After much fiddling around, I cut three strips of printer paper
about 1/2" wide, and folded them over, and that gave me three
paper feeler gauges about .008 thick, which would fit in the
curvature of the gaps. I installed all three at once, and
adjusted the gaps until all three paper gauges were about
the same "snugness" when pulled on.
After adjusting both coil gaps, I put a vertical "magic marker"
mark on the magnet rotor, then slowly turned the engine
over, watching the mark after it passed each shoe.
If the magnet rubs anywhere, it shows up easy as scratches
across the magic marker mark.
Just noticed today that the shop manual shows a person
using a "wire" feeler gauge for adjusting the coil shoe clearance.
I have no such set of guages.
Anyway, this procedure using paper feeler gauges worked good
for me, so thought I’d pass it along, and would be interested in
hearing your tips.