MicroSquirt.com read only forum (Jan.15,2018)

Hi, folks.
I will be using microsquirt in dual spark mode on a Yamaha XV920. Single-tooth wheel on the cam, and a 8-1 wheel on the crank. I understand that my cam synch pulse must occur during the crank wheel missing tooth window.
I would like to make my 8-1 wheel as follows:


The existing flywheel has a chunk of steel (at cyl #1 TDC) to excite the VR sensor. I want to add 6 more in a symmetrical pattern to preserve the flywheel overall balance. However, in this case, the missing tooth will be 180 degrees away from TDC. Will the "Trigger Offset" compensate for this? Will this scheme work at all?

Thanks!

This should work. You would use Delay Teeth (= 4) to compensate for the location of TDC, with trigger offset providing fine tuning.

When I was using an 8-1 wheel, though (no cam synch), I had problems getting uS to synch initially. It would sometimes take a lot of cranking before reading tach. I switched to a 36-1 wheel instead, and don't see that problem anymore.

But, the 8-1 wheel did work, and I can't say for sure whether the synch problem was related to tooth count or not. I can say, though, that there is a lot of discussion on the MS2Extra board to the tune of "more teeth synchs better and faster."

36-1 also gave much better low RPM timing accuracy than 8-1.

Cheers,
Paul

Thanks, Paul.
I appreciate the insight
I will need to add a wheel to get to 36-1. I'll have a closer look.