How to drive Honda RC-51 RVT Ignitor Box?

[OB6D]

I'm using the original ignitor box with the squirt, driving it low level.
This ignitor box has 6 wires. Plus, minus, two inputs, two outputs.
It works with a 5V signal somehow....
The coils wired to the outputs share a common GROUND. (no not +12V)

I'd set it up: Falling edge, going high inverted, COP. Max dwell 3ms.

It works, but at 6k ish there's this invisible rev limiter and i don't get resets, sync losses or anything.

So i raise max dwell to 4ms. This brings down the invisible rev limiter to way lower RPMs. So i drop max dwell to 2.5 later even 1.5
Fires up 'n runs much better, i get up to 8300 RPM now.

As dwell strikes me as too low, i guess it's telling me it needs to be triggered differently. How?

This is the box:

[OB6D]

It's a CDI box. CDI don't need much dwell. Grounded coils are a giveaway. 1ms dwell is probably ennuf. Original ECU controls timing, maybe dwell too, maybe that's fixed.

Anyways if YOU are the next one to use one of these. Go easy on the dwell !!!

And i guess the manuals can use a CDI section.

And bikes are not (half) cars.