From Jim's scope snapshot
https://www.xs650.com/attachments/1661824425101-png.223450/
the "magnet" inside the rotor seems to be 25° lenght according to the distance from the positive to the neg. wave.
sleddog83 said the stock TCI uses the negative wave.
So IF the neg half (trailing edge of the magnet) is at 40°, then the positive one (leading edge) is at 40+25=65° which is very close to what Larryl came out with...
In short: it's possible to use the negative pulse at 40° (stock TCI) or the positive one at 65° (Transmic TCI)
The advantage of the last is you are able to get more advance than 40° BTDC if wanted. It's better to do more then less.
My TCI uses discrete components for the input stage and I want it to be quite "universal".
As a result it cannot be super-sensitive for the XS without being saturated with a 50Vcc pickup !
It still is sensitive: +1.7 to +2v for the pickup to be detected, but the voltage is lower with this big air-gap, hence the bias voltage.
Right sleddog83, it's much simpler to build the TCI around the pickup(s)
Something doable....
About the dwell time, fixed time is mandatory for new ignition coils with low impedance.
The dwell On 1/3 of the period in a point heritage. They had no other choice than doing that way, back in time..
>The stock TCI will run on very low voltages, but the ignition coil won't.
Interresting too! The coil MAY need of longer dwell with e-starter. That's why I asked Jim to test with 6ms, with no luck...