What's different
 

I have been looking all over for a manual for my 1980 750 LTD but keep getting kz manuals.
can anyone tell me what the difference is between a KZ 750 and a 750 LTD?

The LTD was a cruiser kind of look, stepped seat and higher bars with more pull back. Engines would likely only be different in finish (coating or paint), the general manual in engine and braking areas should do fine, like valve adjustment and carb work. One difference I don't remember if the LTD has shaft drive. If it does, that will be a difference if you had to deal with anything in the final drive. Without seeing the bikes side by side I'd say they're mechanically identical, the differences would be in body work, maybe gauges, aforementioned bars and seat, and exhaust system. Mechanical differences would be so slight, maybe where the air box is bolted in, but the serious stuff will be identical.

I hope that helps. You also may find a free version for your bike looking online. I've gotten them for my KLX250 and KLX650.