[seruzawa]

No KZ550 engines in junkyards? The ninja650 engine is entirely different, different electrics,water cooling.... everything. I think that someone is pulling your leg.

You should check the motorcycle junkyards for a GPZ550 engine. Maybe a plain KZ550 engine from that era would fit if you can't find the GPZ engine.

 

[seruzawa]

Once again the GPZ600 engine is entirely different. The only engines that are going to work are direct replacements from other 550s from the same time period yours was built. If nothing else the drive sprockets from other engines are never going to line up and the electronics will never work in a million years. Your electronic connections from the engine must match the ones on the frame. Only another KZ550 engine will match.

 

[seruzawa]

Well, it's likely to fit. Is there any way you can compare the motor mounts?