Hi all,
Just an update on my issue. After much investigation it turned out not to be the stepper motor but rather a faulty NGK CR9E spark plug on the rear cylinder noting that the plugs were only 4 weeks old. I noticed that the rear exhaust was running cooler than the front so on a long shot I replaced both plugs with CR9EIX Iridium and bingo, issue gone. Bike now starts and idles correctly. My assumption is that the faulty rear plug caused the erratic idling so the ECU was ramping up the fuel to compensate.