It appears that the 87-94 diagram calls the decompression solenoid a "starter solenoid controller" and shows it round.  The 95 and later diagrams call it a "decompression solenoid" and show it square. On all bikes it is the same thing.....the bulky solenoid under the fuel tank that pulls on the cable....when told to do so by the decompression controller

On all the diagrams they show a red and black wire that comes from the decompression controller, and a black wire that ultimately connects to a black/white wire which is a ground.