XJ650 Ignition Electronics onto a XJ750?

I have a 1980 XJ650 Maxim, whose engine blew, so I'm swapping in a 1982 XJ750 Maxim engine. My shop manual does not list separate ignitor boxes or other engine electronics for the 650 vs. the 750. Can I just swap my 1980 650 electronics onto the 1982 750 engine?

 

82-83 650 maxim, 82-83 750 maxim, midnight maxim, and 81-83 750 seca use part #5G2-82305-10-00 Yamaha IGNITOR UNIT ASSEMBLY (TCI). These are the YICS series bikes, and use a different timing spec than the early non-YICS bikes.

Your best bet is to get a TCI unit for the YICS motor to get it to run properly.

Ghost

 

Thanks.

What about the pick-up coils or the ignition coils? I apologize if I'm confusing terminology here, I'm still learning my way through the ignition system lingo. I'm referring to the part that is linked to the crankshaft, which I believe is the pick-up coil, as well as the units located elsewhere on the bike, which I believe are the ignition coils?

 

The pickups and ignition coils should be compatible. The main thing is that the TCI includes logic for the advance curve, which is different for the different engines.

The one other possible issue on the pickups is that the 650 pickups use a four-wire harness, and the 750 ones use a three-wire harness (shared ground between the two.) This means that the wires at the TCI-end connector would need to be redone to match the pinouts of the 750 TCI.

 

Don't forget the new motor uses an electronic tach and your pre-YICS motor has a mechanical one.

 

Got it, thank you. I think I may just remove the original instrument cluster, forgo a tachometer, and install an aftermarket speedometer.