I have removed the ignition coil from my 96 Road King.. I have an ohm meter and want to test to see of the coil is bad. The coil is a Crane "HI INTENSITY COIL". It has 3 posts ( - + -) above where the spark plug wires plug in. I'm just not sure how to test this thing.

 

I take it this is a coil set up for "dual fire" or firing each cylinder individually, not waste spark like the original coil was, correct? If so, then what you really have is two individual coils fused together, sharing a common + on the primary side and a common ground on the secondary side, not a single coil.

Ohm meter on low ohms, probably whatever the lowest range is. One lead on +. With the other lead, touch (firmly) one of the - terminals. Should probably read <5 ohms, but it will vary depending on a lot of things and you may have to find a spec. If it is in the 2-10 ohm range, though, that's probably fine. The other - terminal should read virtually the same. That is, if one is 3.1 ohms and the other is 3.2, I'd call that close enough.

Next, with the meter set on a high scale, like something around 20K Ohms or 100K ohms, put one lead on one of the high voltage connections (where the spark plug wires go.) With the other lead, touch some metal on the coil that would bolt to the chassis (a ground). Should read high resistance, not sure on your spec, but 20k Ohms? More or less. The other lead should read the same.

Note that some coils will open up when they get hot, so unless it is totally dead, that can cause problems trying to diagnose them.

 

Fixed it for you Doc.

 

Thanks Dr. Hess. When I go from + to - either way, reads:4
I guess I'll need to wait until I'm home to check the high voltage connections, no good ground in my office.

 

man, this is all brand new to me. here's what i removed, from + to either - it's reading 4.. but from where the either spark plug wire goes to a ground (in a standard 20a receptacle in the wall even) I get nothing. zilch. Not confident that I'm doing it right.

 

your primary winding should be 3 to 5 ohms + and - post both sides and your secondary should be between 10k and 20k ohms - post and spark plug lead both sides
your exact numbers for your coil are probably online somewhere

 

By "ground" I mean ground on the coil. Try to find a bare metal spot on the coil assembly, probably around where it bolts to the frame. Your primary numbers look fine. Why are you testing this?

 

Yeah, thanks. I always get that mixed up. Why can't we just call it "Waste Spark" like everyone else does?

 

This terminology gets even more confusing since several different ignition manufactures use reverse definitions from HD.
From twintec
"Single fire and dual fire refers to the number of times the spark plug fires during each four stroke cycle. The terminology is somewhat unique to Harley-Davidson® engines and is by no means consistently applied. For example, Custom Chrome Industries, one of the largest distributors of Harley-Davidson® aftermarket parts, uses the opposite terminology. Their single fire systems correspond to what most other companies refer to as dual fire. "
http://www.daytona-twintec.com/tech_evo.html



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i'm testing because i'm not getting any fire. replaced plugs, plug wires are good. From what I'm being told it has to either be the ignition coil or the ignition. I'm hoping it's the ignition coil.