Compatiable engines for '81 750 swap?

Hey guys, I'm looking for an engine to swap into my 1981 KZ750 e2 and was curious if anyone could chime in with what would work. I've read about swapping in a 1000 but I'd like something that doesn't require welding. So mainly, years that work and maybe what models. I found a GPZ 750 out of an '85 but I'm not sure if that's too new? Sorry to ask these newb questions but I couldn't find too much on this topic. Thanks for any help!

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I'm just needing a replacement engine, mainly because that is considerably cheaper than getting 810 pistons and a bore job.

I didn't think of the ZR750, I'll have to look into that. It would be cool to have a slightly modernized engine in there.

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76-85 KZ650-750's all bolt in, motor mounts on 82-up GPz, and 83-84 KZ750L's etc are rubber isolated but all the mounting points on the engine are the same.

Its a simple bolt in afair.

Ignition systems differ, from points, to electronic with mechanical advance, to full electronic. All the iggy plates will bolt into any combination of engine/iggy. The stators differ from early 2 wire to later 3 wire setups, again you can interchange.

Keep the stator/ignition setup from your E model, swap em onto the donor engine

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The KZ650 and early 750's use the lower mounting point in the engine as well as the upper mounting point on the front of the engine. The lower mounting hole is where the engine gaudrs bolt on.

On the newer rubber isolated frames, they made the lower mounting point redundant, and only use the upper mounting point on the engine.

There are tabs welded onto the lower frame to mount crash bars on the rubber mounted frames....but it is lower and further back so the early crash bars wont bolt up.

The aftermarket motor guards for the 1982 GPz750 and 1983 KZ750L3 are different and do not interchange (although the motors are essentially the same). I do not recall which year (1982 or 1983) that is the odd one out.

Here are the diferences in the frames. Pictures are worth a thousand words.

750L ( also rubber isolated GPz ) notice the extra brace welded in to stiffen the frame.



Early solid mounting, this is a 650 frame, but the 750E are the same mounts.



ALL the engines have the provision for the extra mount, Kawasaki changed the frames, but the engine castings all have the extra mounting holes

Good info to have! I found an '85 GPZ 750 engine I'm debating on getting, but it seems slightly spendy compared to regular KZ engines at $400 plus $200 for shipping. Might be worth it though as the GPZ's are a bit higher output.

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