I had a intermitent slow or no start problem. I changed the switch and
that helped but would still not crank all the time. I added a new ground
wire to the starter replaced ground to body from the battery, and added a
new postive wire to srarter using new ends and shrink tube. I used heavy
wire for postive cable and heavy plastic to cover wire were it was needed
so it would not ground out by rubbing. I need to get some pictures put
up.The Van cranks like a Mad Dog now. I have a 27 year old van and the
battery connections were not clean at all. I really dont like to have a
van that only starts when its in the mood. I did not have a problem  with
the starter issue until around the 26 year I have a high compression
engine and the stock Bosch starter works fine as long as you get Voltage
and amprage to it.

Bill Witz 84 westy Old Paint