Kz650 vs kz700

Just curious if someone could shed some light on the differences between the 700 and 650. Can't seem to find much info on the 700 obviously an 84. But I am building a 78 kz650 and have been looking for a parts bike. Found the 700 cheap it runs but I have a lot invested in parts for the 650. Aka gasket carb kits ignition conversion complete gasket set exhaust. So I'm not opposed to building the 700 instead and dropping it in the 650 frame. But some information would be great please and thank you!

The KZ700 is basically a smaller 750-4 due to import tariffs at the time. 694 cc vs 738 cc for the 750. The 700/750s have a Hy-Vo cam chain w rubber slipper cam chain guides, electronic ignition & 3-phase charging system. A 78 KZ650 has a roller cam chain w roller guides & came stock w points ignition; the 70s 650s had various different charging systems. For a future upgrade on the 700 you can swap 750 cylinders & pistons to the 700 & it should be fairly straight-forward.

I do not know if the 700 engine is a direct swap to the 650 frame. I'd guess yes, but that is just a guess.

You can compare gaskets & stuff at Partzilla.
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Adding to what Martin_csr said...the 700 is a 750-4,...... debored only for political reasons . Harley-Davidson asked the US Gov to impose a tarif on any imports above 700 at the time...thus to slip under the tarif all Japanese manufacturers de-bored their 750's in those years to 700s........anything you can do with the 700, you can do with the 750-4 as,physically, they are the same.

..as far as I know, any 700, or 750-4 should go right into the 650 frame, as the KZ750-4 was really a factory bored out, hot-rodded, internally improved, version of the KZ650 in '78.

The 700 engine won't fit in a 650 frame without modding to change the engine mounts.

According to the diagrams at Partzilla, the KZ700 has the same crankcase set as the 750E. I think what's different about the 700 from most of the earlier 750s is that the engine is rubber mounted, so the frame is different and the engine guards & engine mounts are different.



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martin_csr wrote: According to the diagrams at Partzilla, the KZ700 has the same crankcase set as the 750E. I think what's different about the 700 from most of the earlier 750s is that the engine is rubber mounted, so the frame is different and the engine guards & engine mounts are different.



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...in which case the engine should fit. That's good news. I thought the engine was changed slightly to accommodate the different mounts.

I wasn't sure, but I knew that there was a difference in the engine case guards because of the engine frame mounts being different.




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I'm always impressed with the foresight of Kawasaki to make things backward and forward compatible, at least as much as is practical.

I guess Kawasaki made the KZ650 engine & crankcase so robust that there was no real need to change it, not even for the bigger cylinders.




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