I was wondering if RE used a narrow-band, or, wideband sensor.
Your chart clearly shows a narrow-band sensor.
good work.
The graph is a GENERAL graph for O2 sensors - not from Royal Enfield.
RE is not a high performance engine as we all know, so it does not need an expensive more sophisticated broadband O2 sensor which will serve no purpose for its performance. Moreover, broadbands usually have 5 or 6 connecting wires, instead of 4 wires seen in RE.
The numbers on the Multimeter are real values from my G5.