'78 KZ650SR. No Spark. No Pop. No Fireworks.

I do not have access to FSM for the early D models but you can pull down a parts list (covers D1,D1A, and D2) to see what some of the part changes were/are. It is located here
jarlef.no/Kawasaki/PDF/Z650/Files/PartsD...am-KZ650SR_D1-D2.pdf