Ignition coils off other bikes

xjwmx said:
I and several others have been using a Honda "MP08" stamped coil with a 3 ohm primary for a long time with no issues. It is plentiful and inexpensive and does not make anybody any money.

There are no precision resistors in the TCI, which says the 1/2 ohm difference completely insignificant. Not only are there no precision resistors, but all the components on the board have 30 years of aging and drift. But I defy anybody to be able to tell that from the operation of a TCI. ;)
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With the Honda coil, what type of wires and plugs and caps are you using? Resistor or non?
 
Skenandork said:
With the Honda coil, what type of wires and plugs and caps are you using? Resistor or non?
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Non-resistor wires, aka metallic core wires. Non-resistor plugs. NGK resistor caps.

Edit, just to add here, those are 7mm wires that fit the best in the Honda coils. I can only recommend the MP08 type Honda coil, the two generations before that (much larger coils) have a worse than "BAD" reputation.
 
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Skenandork said:
Rodger that! Thank you. Any idea if this coil would work with a GN250 box? I'm not too confident in my TCI box as I've never seen my motor run as of yet.
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The MP08 "Honda" style coil will work with OEM TCI or the GN250 "Gonzo" igniter.

There is a troubleshooting method for XS TCI ignition systems that basically involves checking and eliminating everything else except the TCI Igniter Unit - attached.
 

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jpdevol said:
The MP08 "Honda" style coil will work with OEM TCI or the GN250 "Gonzo" igniter.

There is a troubleshooting method for XS TCI ignition systems that basically involves checking and eliminating everything else except the TCI Igniter Unit - attached.
Click to expand...
Thank you again! I'm basically trying to hear this motor run for as cheap as possible right now, and go from there. I found many good threads on testing and I did all the ones I could find. Coils has good primary and secondary resistance. Pick up with both around 750 ohms each. Got power to the coil all day long.
 
There are a couple "semi-off-the-wall" checks before replacing parts:

Verify good, solid continuity of engine cases to battery (-);
Test resistance of pick-up wires at the disconnected TCI Igniter connector (they can break) W/R to Bk/W, W/G to Bk/W
 
jpdevol said:
There are a couple "semi-off-the-wall" checks before replacing parts:

Verify good, solid continuity of engine cases to battery (-);
Test resistance of pick-up wires at the disconnected TCI Igniter connector (they can break) W/R to Bk/W, W/G to Bk/W
Click to expand...
I have a dumbass question! So I'm looking for 12v consistently throughout the cases and frame?
 
No volts, just really, really good continuity to ground (battery -) - as in 0.000 Ohms:)
 
And should I test both sides of the connector or test resistance on the TCI unit itself? Is the a number I should be looking for?
 
Yes on the ohmmeter, battery negative to cases.

Unplug the TCI and test the pick-up wires back through the harness - should read the same resistance as pick-up specs (or very close to 750 Ohms).

There are no specs - that I'm aware - for the TCI unit itself
 

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