I’ve been working on my brothers 99 superglide and it’s been having some issues that hopefully someone can help with. I guess the best place to start is the beginning so here goes.
A couple weeks ago we were on a ride and the bike started sputtering like it was out of fuel, so we limped it to a gas station filled up but then it wouldn’t start. After a jump we made it about 40 miles or so and it died again. Long story short he blew the stator and the voltage regulator. We replaced them but while looking it over I noticed the plugs were fouled as well. So those were replaced too.
We took it out and put a couple hundred miles on it, after stopping for gas he noticed it was not running smooth and thought he’d gotten some bad gas. So we drained the tank and added new gas and some additive to clean any gunk that may have gotten through. But again when we pulled the plugs they looked like they were fouled. So we replaced them again. We went out again and rode about 60 miles or so and he started feeling the same running rough scenario as before. We pulled the plugs and they weren’t as bad but definitely did not look like plugs with only 60 miles on them.
Since the bike had no issues prior to the stator going out I wanted to check the coil and wires to make sure they were ok. And now we get to my questions...
i checked the wires with my meter and they tested good.
I tested the coil and got the following results. From tower to tower im getting 12630 ohms, from what I’ve read it’s supposed to be between 10000 and 12500, so it’s close but a little over?
Next I pulled the connector from the coil and tested between the 2 outer pins (which I think is correct?) and I’m getting 1.1 ohm which from what I read is supposed to be between 2.5 and 3?
If what I’m getting is right than I’m thinking the coil is no good, if that’s true could that cause the fouling of the plugs? Or is there something else I can test or look into that may be causing this? Any help would be great. Thanks.

 

If you want to narrow it down to the coil, test the cam sensor. You can unplug it under the pipe side frame rail and use your voltmeter. The specs are in the manual.

Your test point to a failing coil, but I like to rule out things upstream as well.

 

thats a good point, I’ll check that out tonight and see what I get. Thanks!!

 

Have you done a compression check or used a borescope to check the condition of the combustion chamber? Could be a number of things gone wrong, like a broken piston ring, burnt valve or even a cracked or broken piston skirt, that keep fouling the plugs.

 

I don’t have a borescope unfortunately but I’m going to do a compression test this weekend when I get over to it. I’m hoping it’s not anything with the cylinder and was really hoping that this was all being caused by the coil and/or something related to that. But we’ll see.

 

So you only have 1.1 ohm between the primary terminals on the primary of the coil. Then cool is no good.. should be at least 2.6 ohms.. time to replace..

 

i just ordered a new one, hopefully that fixes the problem.

 

ok maybe I’m looking at this wrong, I just ordered a new coil and when I tested that one out of the box I’m getting 1.1 to 1.2 ohms between the two outer most terminals on the coil. There are three terminals inside the plug housing, I’m testing between the 2 outer ones is that correct? And if so how could I be getting the same from both?

 

The primary side of the coil is the 12 volt connection and then the trigger be it a single fire or dual fire That's where you should be getting your 2.6 ohms.. If you're talking about between the two terminals where the plug wires connect then you should be somewhere around 11,000 to 12,000

 

yes that is what I’m getting from the terminals where the plug wires go, I believe it was about 11,400. But the other terminals on the the three little terminals, I’m testing the two one the outsides, there are three in a row. I’ll take a picture and upload it in a couple minutes.