82 xj650 motor into 82 xj750J Maxim?

Engine looks bad, corrosion beyond repair. It runs, but not so good...maybe I just need to remove and thoroughly clean the carbs. Sounds backwards, but with what I think is a basket-case motor in my xj750 with 40k mi. I'm thinking of swapping in a my good xj650 motor & carbs with 20k mi. On the 650, the clutch basket and drive output need replacing, and the motor remains disassembled for that repair.

I also have the xj650 wiring harness and would like to swap out the cruddy (rusty inside) instrument panel with the xj650 gauges and round headlamp. I figure I'll also need the xj650 CDI & regulator if I swap out the wire bundle. By the way, the existing system has some ground issue, probably corrosion. It's better than the original harness I swapped out, there was a short circuit in the bundle probably due to chafing against the frame.

I've heard of a 750 going into a 650...and only engines from certain models will swap over. Anyone done such a swap?

 

The only real caveat is matching YICS motors with YICS motors (tach drive differences) and Maxim with Maxim (shift mechanism differences with the Secas.) If you're talking about a 650 Maxim (YICS) motor going into a 750 Maxim, you should be able to pull it off easily. If it's an earlier 650, as long as it came from a Maxim, then you have a little more work to do but it's still pretty straightforward. It's when you start trying to mix Seca-Maxim it gets interesting.

 

Hi...

First XJ750 Maxims (and Secas) had a rectangular headlight and rectangular aux light. Many Maxim/Seca owners have swapped in a round headlight for appearance sake. Had to swap triple tree and installed tapered roller bearings instead of the stock ball bearings. However you may run into problems with the exhaust mount points. Compare and measure the frames etc out but it's all the same engine, shouldn't be too different. Change to the xj750 engine rather than tear down the 650 and change or fix the trans. I replaced the plugs and then found out that the clutch was shot from the newfound power.

Regards,
Xing

 

Looks the the headlight bracket I have from the xj650 (round headlight) has similar attach points as the xj750 (rectangular) headlight bracket.

I fear the clutch is already shot on my xj750, I pull the lever and it does not disengage. As in running in 1st gear while on center stand it will not shift to N or any other gear. I can turn it off and pop it into N or up to 5th...seems like the clutch is toast...I'll try adjusting the clutch lever before I draw that conclusion.