TZR250 3MA

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How to read out digital

3MA CDI > CDI (facts) > Digital reading out oem curve

The pulse generator give's a more accurate Hz's point for reading out the Oem Curve.

First part it was a bid tricky to find the correct location for the pulse to be given, but after a few setups found a place where the pulse was good enough for the IC to work with.

Measurements from the IC where taken at pin13 (pickup signal) pin22 (ignition signal)

Explanation off the graphic:

Green: Pickup pulse
Yellow: Ignition pulse

Measuring is done by counting the grid points (with help off the Oscilloscope function)


780 rpm - delay 3550 us (3,55ms)

780rpm takes 1 minute to complete - 1 min.=60 000 000 us (so 780rpm takes 60 000 000 us to complete)
780rpm 1 rotation=60 000 000 / 780 = 76923 us

One crankshaft rotation takes 76923 us, we also know that 1 rotation = 360 degrees.

Degrees traveled in 3550 us = 3550 us *360 / 76923 us
The result is 16,61 degrees.

This is not the degrees we are looking for, as the pickup location is not at zero degrees.
The mechanical angular is 36 degrees at a 3MA

So 36 - 16,61 degrees =
19,39 degrees (fire point at crank location)

The rest is done the same.

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