Burning CDI box, melted green wire

[postwarcomet27]

Hi ive recently got an 81 cb 750 for a good price.  the only problem is the wire is melted from the guy that had it before me.  Apparently he tried jumping the bike from the solenoid instead of the battery and it started smoking.  After buying the bike I charged the battery replaced the cdi's and tried to start it.  I started smoking and fried the left cdi box.  I smelled a wire burning too and found a melted green wire in the wiring harness.  the wire was covered in tape but the coating was melted pretty bad for about 3 inches.

My question is...do I have to replace this whole green wire all the way to its source or can i just replaced what is melted?  Also, when I replace this wire and one of the cdi's start burning again, what would some of the problems Icould be running into?  It looks like i have a ground going to the frame, and only one cdi is burning when trying to start.

thanks
jared

[LukeM]

Trace the wire back to its source.  I'm guessing this is a ground wire.  One end most likely goes to the negative battery terminal, and the other end goes to ground.

The best way to check is to get a copy of the schematic for your bike, and use it to find out where this wire goes.  Once we know that, diagnosing what's making it burn will be easier.

Photos might help as well.
Luke M

[postwarcomet27]

thanks luke,
Heres a pic of the green wire.  I cut he wire were it was melted for the most part.  I cant find a diagram for the wiring on this bike Ive been searching the internet non stop.  Im going to try and rip the tank off to trace the wire.  

Checked all my fuses and they all seem good still.  

Also do I need both cdi units to start the bike?  I have two untouched cdi and Im afraid I will fry another one if both are connected and they are not cheap.


thanks

[postwarcomet27]

here is another pic.  you can see right under the cdi adaptars the fried one.  I disconnected the adaptar and just bypassed it.  Hopefully the pics help out a little bit.  Let me know if I need to provide anymore info or pics.

thanks
jared

[LukeM]

This might be interesting.  Download the Factory Service Manual for this bike, and look at the schematics in chapter 24.  Those should be pretty close to your situation.

As far as the CDI units, it all depends on how messed up they got with the voltage situation.  I'd definitely get the wiring working first before putting them back in service.  It may be easier to check the whole wiring harness against the schematic and making doubly sure everything is where it should be.

Check twice.
Luke M

[TOOLS1]

I am not familiar with the DOHC 750s, but Honda usually uses green wires, for ground. Also you definitly have a dead short.
TOOLS