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

If you are going to put the sensor perpendicular to the wheel, I would recommend using a flat bottomed drill to make the "teeth". On the Yamahas I have worked on this is usually a 8mm drilling for a 5mm diameter VR sensor tip. In fact this is far superior to my early attempts at trigger wheel design, because a 4 tooth wheel, with four indents is reliable at all rpms, that is no sync errors, whereas my attempts at a positive 12 tooth design weren't. I reckon their R&D department or Nippon Denso must have known what they were doing and I was playing catch up!