My 2016 sportster Xl1200T occasionally goes into very high revs (2,500-3,000). A bit scary when coming up to a junction! The only code is P0151 rear O2 sensor. Throttle cables are all OK and butterfly is closed. Only way to reset is spray inside throttle body with carb cleaner, and eventually it will reset. Last week did 420mile round trip in 3 days, no problems. Yesterday did 12 miles parked up for an hour and on ride home went off again at 2,500rpm. Any ideas would be very grateful. Thanks

 

The code indicates a lean condition. That will make the engine rev high.

Throttle cables would affect both cylinders. I was thinking the IAC – Idle Air Control actuator might be faulty but that would also affect both cylinders.

Check if there is any air leaks on the manifold or exhaust.

It might be the injector for the cylinder.

If you have the correct socket you could even swap the O2 sensors to see if the fault moves to the front cylinder.

 

Thanks for that, I will try and change O2 sensors. I am waiting for an EOBD tester from a relative to see if I can read the O2 sensor is working before I swop

 

Might also want to put in some injector cleaner in the tank on next fill up. If an injector gets some dirt stuck in the needle area and cause it to stay open allowing excess fuel to be fed into the cylinder because the fuel pressure to the injectors is constant. That's what caused mine to do that and after running a full tank of gas with the cleaner in it, it hasn't happened again for 12 years now.