Blown CDI?

[iwinulose]

Hello all,
I was on my way to work the other day when my 96' 750 just flat out died on the highway. I had no electrical and when I pulled over I could smell the battery burning, sure enough it was smoking when I stopped. I noticed the Positive battery cable was falling apart so I installed a new battery connector and I am able to get the bike to start but it barely runs, cuts out when you touch the throttle at all, it can rev up if you're super easy with it. Upon further inspection i found 2 wires on the main harness that had rubbed against the cylinder head and it appears that they may have grounded out on the head. One of them is a black wire with a white stripe and the other is an orange wire with a red stripe. I have no tach, no headlight (except for high beam), no brake light, and the right side blinker is spazzing out. I do know that most of those are wired on the same circuit and feed into the CDI. I don't see any other issues with the wiring which is leading me to believe that the CDI may have blown but I wanted to see what other people may think. Thanks for any advice/help you guys may have.

[arsenic]

Everybody blames the CDI, all the time. That's rarely the problem.

[maniac1886]

orange and black with a white stipe, right over the head... Dont those go to the coils?

[iwinulose]

The black with the white strip branches off just behind the engine, goes to the CDI, brake light, tach, and i believe the headlight and blinkers, my guess is its a 12v source. The orange wire with the red strip leads straight to the fuse box. I did have a blown Ignition fuse when the bike died. Replaced that and the bike fires, it just barely runs. I also just installed new coils and wires about 2 weeks ago.

And actually its a 600, friend told me a 750 was swapped in but I can see 599CM3 stamped on the side of the block.

[iwinulose]

So I pulled everything apart and compared it to the wiring diagram for the bike. It looks like the Black wire w/White tracer is the main ground for most things on the bike. When the rubber rubbed away from this and it hit the cylinder head nothing happened since this is a ground. The Orange wire w/Red tracer is a 12V supply wire for the dimmer switch, when this rubbed away I believe it may have shorted the Black wire w/White Tracer. Attached is a highlighted wiring diagram, these are the circuits I believe had the potential to be affected but I still can't make heads or tails of it. I'm not sure if maybe I blew the new coils I just put in or if my original thought that maybe its the CDI is blown or if its something else. I'm going to try to post a video of the bike running if I can but I'm hoping somebody may have some advice. Thanks guys.

Edit: Highlights on diagram are not all correct coloring, Red X's with circles around them are where on the Diagram the wires grounded out on the cylinder head.

[92xjunker]

I don't see where the headlight circuit, which your 'x' is indicating, would effect the ignition at all.

[iwinulose]

The Black X on the headlight is because it blew. The Red X's are where the wires vibrated, rubbed through and hit the cylinder head. The Black w/White tracer which is the main ground may not have anything to do with the problem as the shorted Orange w/Red tracer seems like it flows to all of the highlighted points and those are all areas that I'm having issues. I've got a feeling that it's probably either the Coils or the CDI that are blown but I'm not sure what the diagnostic procedure for this sort of problem is. I don't want to come at it wrong and waste money/time.

[92xjunker]

if it runs, it most likely not the CDI, It sees the trigger pulse and it's firing. since there was a short, did you dig into the loom for melted wiring? sound like clogged carbs to me, every time that description is post it's fuel related, pinched line, vac hose off or decaying, fuel filter where there shouldn't be or clogged and last on the list dirty carbs. May just be a coincidence.

[iwinulose]

I did, I've got the entire front of the bike unplugged and separated (all tape is off) back to where it branches over to the CDI. The only issues I see are the two spots that vibrated through. So I'm guessing it must be the Coils then, which is an awesome waste of $200 since I just put new ones in. >=(

[92xjunker]

test the voltage to them, verify hot spark. then check header temps

[iwinulose]

I tested the leads up to the coils and they have battery voltage (My multimeter is a bit screwed up so I can't say exactly what that voltage is). Dips a little bit while cranking, I'd say about 1v. But what I noticed after a couple of minutes was that the coil I had plugged in to check for spark was getting warm. So I went to check on the CDI and when I grabbed it I damn near burned myself.

[92xjunker]

Not good, shorted coil?

[iwinulose]

That's my guess. I'm going to have to order new coils...again.

[92xjunker]

Measure the resistance, compare to the specs first.

[Kreylyn]

I've recently come to think a possible issue with the CDI is a faulty input to the alternator, which causes it to push out way too much juice, and ends up frying the CDI. This is from speaking with a few people recently who had issues with the CDI being extremely hot.

Excessive heat at the CDI is a very good indicator that there is an issue with it at this point. It really should not get hot at all.

I would suggest you try to find a known good CDI you can use to test with to find out one way or the other. Then, if the bike runs... immediately check the voltage of the charging system to make sure it's not putting out too much. If it is, that needs to be fixed immediately, or you will cook the next CDI too.

Krey