96 heritage Softail speedometer conversion?????
Some things do not make sense.
Reads like you have a non-factory or non-stock bike..a built motor, a non-harley replacement transmission and self reported parts that do not match year..
I believe a 1996 would be electronic and not mechanical.
A properly installed mechanical speedometer can pass a 100,000 miles.
Maybe someone routed the cable from the front wheel to speedometer without regard to placement...too many hard turns of cable can make it get stuck.
Probably turned a few times under tank.
Speedometer would then bind and then either break the cable or destroy the speedometer.
There are bikes much older than 1996 that are still on an original speedometer.
A built motor would be of little concern unless it was spinning past the measurable maximum speed.
If you are having to replace multiple times then it is more of an installation error or other items being improperly addressed and destroying the unit (loose rotor bolt for example).
A loose rotor bolt is something that should not happen unless someone was not following proper procedures.
A properly installed unit should last a long time.
It is rather difficult to offer detailed suggestions if you have parts that do not match year.
Consider review of a parts finder in order to determine exactly what you have on the bike.
Below is a parts link.
Enter year and model.
Then go to parts category.
http://partsfinder.onlinemicrofiche.....asp?make=hdmc







