CDI Test

So I wanted to share this out there as the CDI box seems to cause great pain in trouble shooting and cost of replacing. My friend who recently bought an old Honda quad was having trouble getting his to start. He had narrowed it down a bit but was hoping to avoid buying the cdi box if it was not truly the problem. We got to talking with a fellow engineer at work and he said to try heating the cdi box with a heat gun. He tried it last night and after just a few minutes of heat the quad fired right up and worked all evening.
It's not a fix for sure and I don't really understand why it works but I wanted to share this out there to help folks prove the cdi box is the problem or not.
Has anyone heard of this or know why it works?

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that generally works the other way around, start cold, quit once the box warms up.

I spoke with a EE about it and he said it's probably broken contacts inside that reconnects temporarily due to thermal expansion when the box is heated.

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ntklr650 said:

I spoke with a EE about it and he said it's probably broken contacts inside that reconnects temporarily due to thermal expansion when the box is heated.

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There is a guy on the advrider.com XR650L forum that fixes the XR CDIs. 99% of the failures are from cold-solder joints so this explanation makes sense.

Yes, cold solder joints. Works sometimes with flat TV screen controller boards. Bake them in an oven and things start working again.

ntklr650 said:

I spoke with a EE about it and he said it's probably broken contacts inside that reconnects temporarily due to thermal expansion when the box is heated.

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Click to expand...

I agree[cold solder joints]

IGNITECH.CZ (as in Czechoslovakia) makes DIGITAL REPLACEMENT TCI'S and CDI'S for about $125 each. I have two on my old Viragos.
No, you can't beat that price, or the QUALITY.
This company makes FI systems, for older bikes, too.
http://www.ignitech.cz/en/
Use PAYPAL for the transaction.
Single cyl CDI $67

You can test your CDI. I did my first one in 1976 on a Yamaha YZ 175. Years later, they were done on Honda power equipment.
There are certain ohm readings you get from different wiring leads. Service manuals should lead you through the troubleshooting. That way you know if the CDI is the problem.