11.6.1 Fuel Table Cells Show Grey But The Motorcycle Doesn’t Run Well

First, check for any intake leaks or possible faulty sensors. Tuning should ONLY be done on mechanically healthy motorcycles.
Sensor data is largely dependent on the sensor environment. For example, in some earlier model stock exhausts, the rear sensor is positioned poorly. This ends up causing the cylinder to be leaned out when “tuned”. The standard Harley motorcycle oxygen sensors are also limited by design. The sensor is designed to monitor AFR (lambda) to allow small real time adjustments in high MPG conditions, outside of those conditions, the sensor is unreliable and inaccurate. This is why Direct Links AFR mode using the motorcycles sensors creates a temporary lean condition and target while calibrating steps are taken.

11.5.1 Why Should I Make a Backup?

Direct Link creates a robust image of the ECUs programming. While it is exceedingly rare that such a thing is actually needed or used, it is very handy to diagnose and isolate possible emerging mechanical issues or just to evaluate the before and after. For a few minutes of patience, you ensure the reversibility of any programming going forward.