Extracting ignition curve
Extracting the oem ignition curve turns out to be a challenge.
My first measurements are confusing, consulting Olivier who is helping me on this project.
Seems that the calculation are differently compared with a 3MA CDI.
The CDI should have a steady pulse till 3500rpm (58,50Hz)
This should be 18 degrees
Measured a wide range off Hz, for a good starting point.
Hz RPM Time (ms)
19,03 1141 5,91
19,60 1176 5,66
23,01 1380 4,99
25,69 1541 4,58
32,34 1940 3,66
37,33 2239 3,20
38,88 2332 3,00
42,75 2565 2,83
46,39 2783 2,62
52,94 3176 2,29
58,49 3500 2,06
The IC pulse is there after 33,33HZ so measured it from 34HZ
From 58,50Hz the IC is controlling the ignition pulse
Hz RPM Time (ms)
34 2040 5,17
40 2400 4,36
50 3000 3,41
58,50 3500 2.88
60 3600 2,81
60,66 4000 2,55
83,33 5000 2,08
100 6000 1,76
116,66 7000 1,55
133,33 8000 1,36
150 9000 1,25
166,66 10.000 1,15
175 10.500 1,13
183,33 11.000 1,10
200 12.000 982 (us)
216,66 13.000 932 (us)
To give a somewhat visible indication draw a rough sheet.
Blue = CDI circuitboard is controlling ignition.
Purple = jump from Circuitboard controlled to IC controlled.
Red = IC controlled ignition
Turns out that the IC is not controlling the ignition at all.
It is firing the whole range at the back off the lobe, the shape tells it is just following a natural curve
Giving Pin15 a mass signal, the ignition pulse moves
Normally firing at the back off the lobe, its now giving a free ignition pulse
Measured time
83,33Hz 4,18ms
100Hz 3,41ms
116,66Hz 2,86ms
133,33Hz 2,55ms
150Hz 2,26ms
166,66Hz 2,06ms
175Hz 1,98ms
183,33Hz 1,90ms
200Hz 1,75ms
216,66Hz 1,61ms
Du to the latest discovery, this behavior can be explained
The small lobe length used on my testing machine is way to small for a TZR125 4DL
Se here: Almost solved the problem