TOPIC:

Hello everyone,

I have a 84 kz750 LTD shaft drive. 
hypothetically would the zr7 engine fit into my frame and would the shaft drive gearbox mate up to it?

regards

Jai

I'm gonna say "sure", with some caveats. You may need to fabricate new engine mounts (unsure - but if so, it won't be difficult) and you'll need to split your crankcase to install the transmission from a shaft drive bike. 

It is not easy.  Even skipping the nightmare of switching final drives, which although possible, is not really practical.  

The ZR7 engine is rubber mounted in front, and does not have the extra mounting at the bottom, as early KZ750s.   The ZR7 frame has extra bracket to compensate for lack of engine rigidity.

2nd.  The timing rotor is different, the rotor mounting is different, the timing shaft tip is different.   .....and this poses a problem because the ignition from previous KZs including the Zephyr is different, thus either, you will have to machine a older rotor timing mounting, or modify the ignition of KZ to match the ZR7s, and the ZR7 uses carbs with TPS hooked to ignition box.


3rd.  Even if only swapping between chain driven bikes.  The transmission sprocket counter shaft of ZR7 is longer than any previous KZ, to support a wider swingarm and wider tire. 

Unless you like headaches,...you'd be better off getting a entirely complete bike....and would be probably cheaper in the long run.

What's the reason for the swap.
If the st engine is worn out most of the ZR parts will fit on the st cases.
 

You need to make sure to drill a oil passage to be able to feed the gears inside the shaft drive cover. The chain drive motors do not receive this machining on the finished castings.
I went the opposite way and made a shaft drive 750 into a chain drive 750 and had to plug this oil feed hole which is to the left and above where the clutch rod comes out. This machined face also has to be flush so you would need to be able to fly cut that on a milling machine.
This oil feed hole may or may not be covered by the trans cover, mine did not cover it.