Got a 2004 Sportster 1200 and redid all the wring on it, but lost a spark after doing so. Thought it was a bad coil, so I got a new one only to have the new one burn up again. After fiddling with it now for a couple years too long, I started from scratch, tore everything off down to the frame, and redid all of the wiring properly this time. The current coil I have is blown, reading 0 ohms, so before I order another coil and go plugging everything back in and checking for a spark, what is causing the coil to blow in the first place? I've gone through too many now and don't want to buy another one.
Any ideas are greatly appreciated. Thanks.

 

only if the ecm is bad or one of the coil wires from the harness is grounding

 

Thanks for the reply. I replaced the old ECM with a daytona twin tecs internal iginition awhile ago and got it all timed and set up now. The coil could have been grounding out with the old wiring system, especially since I think there were some things in it that weren't set up properly. With a new wiring system hypothetically setup correctly, there shouldn't be an issue with the coil now, correct?

 

correct. just make sure and use a multimeter to make sure non of the leads going to the coil is grounding

 

How does a coil burn up? I'd figure the primary goes open and not to 0 Ohms.

 

it will show open if the windings burn and break, but when the insulation breaks down it would show 0 Ohms and produce a lot of heat ...if power remain on it then it will show open! ouch! Had a car do this, but it was the ecu.The coil would smoke but the primary didn't go open..as yet lol

 

But if the 0 ohms produces at lot of heat, wouldn't the windings burn and break?

 

Put you volt/ohm meter to AC and attach it to battery or maintance leads. Rev motor to 2000 if you have a tach or fast idle. See any AC?

 

I don't think the motor runs.. Kind of hard to rev to 2000.

 

of course! but if he allows the power on for long enough. But it will eventually melt the copper winding, the primary windings are thicker and can take a little insult before melting away