Resistored COPS vs unresistored COPS

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If the gap needs to be narrowed when running the COP's with resistors, my guess would be that the resistance is to high that was added.

The current flow through the coil should be the same when either a COP or a stock coil is used. The reason for using resistors is the COP coils are about 35% lower ohmage than a stock coil. This allows circuit to conduct better, thus increasing current.

Current is normally flowing through the coils, A TCI interrupts the current flow when plug is fired. This is opposite what a CDI does. This makes it easy to measure current flow through the coils in a TCI circuit. Inserting an amp meter in series with stock coil will give current draw. Then insert a COP in same circuit and measure current flow again, it will be higher. Using Ohm's law, proper resistance value can be determined. I would assume it should be about 1 ohm.

Then the wattage rating for the resistor could be calculated by inserting the calculated resistor in line and measuring the voltage drop across the resistor. This test resistor could be too low a wattage for continuous use, but will survive long enough to get the needed voltage drop reading.

A better way to determine needed current flow for a COP would be to measure current flow through coil in a bike that was designed to use the COP coil, this would take out variables that are introduced when putting COP in a circuit not designed for them.

In the case of the Ignitech, once proper current flow in determined, the dwell setting can be used to adjust the current flow through COP.

I would think that if plugs need to be gapped narrower, that not enough current is flowing through coils, this would result in a magnetic field that is weaker when the TCI interrupts current flow. This would then create a smaller induced voltage in the coil secondary circuit thus the spark created would be less robust.

Attached are a couple of pictures when I tested coils using an Inductance meter. Static ohms reading for a coil are not a true reading.

Gary
 

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Bill Seward and myself have 1985's with cops without resistors. Neither have had problems.
 
Ive got a 98 that i run the resistors on. I didnt want to take any chances and dont know if/when ill change to the ignitech unit. Figured better safe than sorry, lol.
 
Still don't have any problems with my '85 with unresistored COPS. Bike runs great.
 
how do you know if your stock ecu is analog or digital? I have a 2005 and trying to figure out if i need to add resistors or not and what plug gap is best
thanks Pete
 
By the way. Is anyone using the ignitech with cops? What settings are you running?
 
By the way. Is anyone using the ignitech with cops? What settings are you running?

I have COP's & Ignitech, Dwell setting at Auto. I have had them in for about 4 years now.

Iridium plugs gapped at .035". Previous gap was .032". I went to .035" after discussions with Traumahawk.

Gary
 
Most high energy ignitions use wide gaps on the plugs. As much as .050 with platinum plugs. I've got cops w/resistors in the harness. Running .030, but that can change.
 
Anyone running resistered COPS and the newer Dyna 3000? Curious what you're running for gap. Curious if this is causing my cruising issue I can't seem to iron out...I recently added holeshots & Seans jet kit...keep making jetting changes but never thought about the spark side of the equation...Dyna is set at factory...thx
 
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