Vintage Dirt Bike Q & A

Does anyone know how much voltage, (DC) should come from the CDI unit to the coil when it is kicked over? I am reading about 3 volts, which seems a bit low for the coil to step it up. The stator seems to be pushing plenty of AC up, so is my CDI DOA?

Did you use an oscilliscope to measure the 3V?

I don't have a CDI in my Honda, just points/coil. I do have several bikes with CDI and it is more like a ~200V zap to the coil then a sustained voltage.

If you measure the coils primary and secondary resistance I can do one of mine for comparison.

Just drifting a bit. I looked up CDI in the US Patent base. They are a relatively simple design in their lowest common denominator. Just some AC to DC retification, a sensistive gate SCR<similar to the silicon found in light dimmers> and the equivalent of a photo flash capacitor. I ended up making my own albeit w/o any advance or other nicities for a Suzuki.

I just used the old Radio Shack special voltmeter to check if there was any juice there. I am going to pull a CDI from one of my other CR's to see if it helps, possibly a coil also. Thanks for your input!

Yup! Bad CDI. I stuck another one in from one of my running bikes, and low and behold plenty of spark.

Thanks!