Originally Posted by supershaft
Each sensor goes to one coil. No wasted spark. That's how you run a 360 or 180 degree crank with no wasted spark. Or you can have the same setup for dual plugging like some I know have done.
Electronic is better and cheaper but that doesn't change the fact that I almost never see mechanical advance issues despite everyone and their mother on the net suggesting others might have them. Open mind? If I didn't have that I would have jumped on the sticking advance bandwagon decades ago but guess what? I don't see it. It's great when what I hear is what I see but . . . . And then there are the ignition curves available. With one exception so far, they don't empress me. I just dual plugged my bean can bike. It took about five minutes to readjust the curve from 6 to 28 degrees versus 32. I might delay full advance rpm in the future and that will take a bit more time but I can get the curve exactly where I want it. Not so with most electronic advances I have seen.
I still don't know how advance comes into play at starter motor RPM?
When mechanical advance is stuck at full advance (as they often do) it makes the bike harder to start. I have had sticking advance weights in nearly all of my airheads, perhaps we just use them harder over here in Australia? I often see rusted internal parts inside original BMW beancans.
As the hall effect sensors in the cam driven bean can are triggered every 180 degrees of crank rotation using two active sensors at 180 degrees apart in the bean can would trigger a pulse at every 90 degrees of crank rotation (as the cam/bean can is rotated 2:1 to the crank) seems to me that you would still have a wasted spark on each cylinder, and use twice as many sensors to do it. Also getting the two sensors mounted precicely 180 degrees apart is difficult unless you use an adjustable mount on one sensor.