erratic loss of power

[natemoen]

Dove into the ignition system tonight determined to find my gremlin. What I found has me perplx perp ...I'm stumped. The Excel coils on my 79 Special are providing a primary resistance of 3.5 instead of the suggested 1.5, the secondary reads 22.7 K ohms rather than the 15K ohms and there is no ballast resistor to be found anywhere near the coils or any where else for that matter. Can any one offer an explanation how this b_tch is running at all. Most of the time she does run quite well. I did find a horrible excuse for an electrical connection to one of the coils that I suspect may be my gremlin. Ran out of time so the wiring fix will take place the first chance I get followed by a test ride. Are the resistance readings I'm getting within a range that will allow my PITA to operate properly? And........ why no resistor?

Thanks to all much wiser than myself who are willing to share the wisdom.

You stated that they are Excel coil. Since they are aftermarket coils most likely they are 3 ohm coils instead of the original 1.5 ohm coils. Since they are 3 ohm coils you they need to remove the ballast resistor, which is why you cannot find one. Just to make sure though the ballast resistor is going to be a silver rectangle that is mounted on the left side of the coils under the frame rail. It is about 3/4" wide and 2 1/1" long and will have 2 red wires connected to it.

For the secondary resistance did you check the ohms with the plug caps on or off. If you left the caps on then that is where your high reading is coming from. Most likely you have resistance caps and I believe they come in 3000 and 5000 ohm caps. Look on the caps it should say what they are and if not pull the caps off and check just the caps and see what they read. Check the coils with the caps off as well.

[proctor1]

After market coils

So what I hear you saying is.........The readings I'm getting are not unusual for the coils I have and the case of the missing resistor should not pose any problems for my machine. Yes?

Anyone with an opinion on after market/performance coils please join the conversation.

[Toolmaker Tim]

Coils and ballast resistor

The way it was explained to me, and everyone else on this site that happened to catch the thread ( I don't remember the title), the ignition system needs 3 ohms to operate. The stock coils are 1.5 ohms and the ballast resistor is 1.5 ohms, so the total of the two is 3 ohms. If you use coils with a resistance of 3 ohms AND the ballast resistor you get 4.5 ohms and things don't work. I think this was explained by 3Phase, but I may be wrong. Whoever explained it made it simple enough that even I could understand it. The bottom line is your coils by themselves are enough to make the ignition system work correctly.

[natemoen]

So what I hear you saying is.........The readings I'm getting are not unusual for the coils I have and the case of the missing resistor should not pose any problems for my machine. Yes?

Anyone with an opinion on after market/performance coils please join the conversation.

No the reading should not be a problem. I would still check your plug caps. I would guess if your getting 22K for the overall ohms then your caps are most likely 3K ohm caps but usually 5K caps are used (not that it matters though you can use non resistor caps if you want). So look at your caps and test them all individually and then check the coils without the caps as well just to make SURE the the coils are good. Because if your caps are 5K then your coils are only at 12K and I believe that is to low!

When you have the caps off you might even want to clip a 1/4 inch of wire off the end before you put the caps back on just in case there is some corrosion there and then use some dielectric grease when you put it all back together. Just for S & G you could even pull your wires off and check them just to make sure they are good as well.

Lots of people here are running aftermarket coils. I just put some on a couple weeks ago. The aftermarket ones are not 30+ years old and they put out more power for a stronger spark, cant go wrong there.

Just remember sometimes troubleshooting is more about figuring out what is not wrong than it is figuring out what is wrong.

[proctor1]

Happy day

After closer investigation and the great advice provided here about proper operating parameters I may have solved my "erratic loss of power".

Since the resistance provided and the lack of a ballast resistor provides an acceptable operating range I was left to focus on the pickup wires and the shoddy electrical connection to my coils. I undid the clamps holding my pick up wires and checked every mm for breaks. Unable to locate any problem I re-secured them and moved on to redoing the crappy connection. Upon completion I secured all of the wires, neatly to the frame, that run to my coils. Just for reference, they were all dangling from the wiring harness to their connecting points. I reinstalled the tank, fuel lines and seat to set out on a test ride.

Eureka!!! Unless it is just a temporary means of trickery by the beast I so fondly refer to as my PITA. I put down about 30 or 40 miles without incident. I was even able, for the first time since I can remember, to cruise along with the RPM's under 3,000 without a jerking sensation. I use to correct this behavior with a down shift or more throttle.

The help from all contributors here is greatly appreciated. A little encouragement and some shared wisdom goes a long way to helping achieve success. Many thanks guys.