IMO, in this one instance, the manual is incorrect when it comes to a Rotax. Even two wraps of the rpm lead around the spark wire may not be sufficient. I have three. The rpm lead is only measuring flux changes as the coil discharges. Don’t quote me on this, but the Rotax coil wire may have better insulation, hence a weaker signal to detect. If your engine is stumbling at high rpm’s, you might have a marginal coil, but doesn’t seem to be the case.
There must be other Rotax guys out there running a MyChron on the Forum. It would be nice to here from you on how you have the sensor attached.
LAD Specialties customer / tony kart / rotax / kt100