SUZUKI DT-25 Late 70's Ignition

[SeaKaye12]

Hello all.....
I just acquired a nice Suzuki DT25 S/N

D-13792

I'm intrigued by the ignition; there is no mechanical adjustment of the mag-plate fir timing. No link-n-synch or any of the usual linkages that adjust timing as the throttle is advanced. The twist grip connects with a simple cable to the carb butterfly. That's it.

Can anyone share information with me regarding this ignition? How is the timing advanced and how can it be tested?

Interesting motor for me; I usually work on Mercs and OMC.

Thanks!