1981 wiring harness

can i put a 1981 wiring harness from an xj650 on my 1982 xj650

 

according to the list below the only different part is the sidestand relay is not in the 81 harness
so the simple answer is no.
the wiring from the pick up coil is where you have to look with out the relay all 4 wires go to the tci. with the relay 2 wires share a common connection to the tci with a wire running to the relay in the 4th position.
the tci unit is not the same
but you could do it if you added the sidestand wiring setup
the haynes manual has both wiring diagrams in it to to compare.
haynes 650-750 free down load
http://www.manualslib.com/manual/837861/Yamaha-Xj750.html

XJ650 Maxim and Midnight Maxim models:

Flasher: near the steering headpipe, on right side frame rail, under the right side ignition coil.
Flasher canceller: under the rear of gas tank, behind ignition coils
Starter motor solenoid/relay: on right hand side, attached to and behind the battery box.
Diode block: inside the headlight housing.
Starter/Ignition cut-off relay (no color): behind the turn signal self-canceller. (note: the drawing and the description in the service manual is wrong).
1980-81 Sidestand (kickstand) relay (blue): did not use.
1982-84 Sidestand (kickstand) relay (blue): frame bracket outbound of LH frame tube, just behind the left ignition coil.
Headlight relay (yellow): behind the left frame side cover, on the plastic regulator-rectifier mounting plate. (note: the drawing and the description in the service manual is wrong).
Neutral switch: in a hole in the bottom of the crankcase, just "outside" of the oil pan, on the bottom of the engine, up inside a recessed "well".

 

I wanted the wiring harness to do a minimum

 

if you plan on removing the side stand relay you can do it, as it is removed for testing and bike will run
down load the haynes manual and look at the 650H (81) wiring diagram and the 650 J K (82 83) wirediagram
have you seen the minim wire diagrams posted on this site? i can post the if you need to see them

 

I do have the minimum wiring diagram. I'm going to follow it when i get a new wiring harness

 

Also, 81 has a mechanical tach, 82 has electric tach

 

I actually found an 1982 xj650 wiring harness on ebay so i hope i can make it work

 

I wonder though, why aren't you just using the harness the bike already has?

 

Honestly i'm scared ill mess something up so i'd rather get another one to try it on then replace if it turns out right.

 

That is a good reason.