Miller Performance is the only company to bring an affordable mass air flow conversion to the market with a long standing, proven track record.the availability of good AFMs will drown out the bitching re. changing to a MAF. My sense is that the latter group is louder right now. But …For example, at 2500 RPM spacebar counter the value should be higher than at idle but lower than at 4000 RPM. If the live data does not match this behavior, it means your Mass Air Flow Sensor is dirty or has failed.old rider, that is 180 – 45 = 135 bpm. Now you apply a modifier to this number depending on your health and training status: – 10 bpm If recovering from major illness or over training.