But ReadyXB is right. A stock bike in good shape shouldn't misfire.

The old wives tale of a vehicle meant to run 'lean' for the EPA has always been hogwash. An engine running even slightly lean will have terribly high NOx and Hydrocarbon (HC) emissions, both of which are scrutinized by the emissions police. MFG's don't shoot for lean, they shoot for stoic (14.7:1 in CL). 14.7:1 is not lean, it is efficient and clean burning. An engine running even slightly rich in CL will have higher Carbon Monoxide (CO, also scrutinized) but will have better throttle response because when the engine needs the extra gas, *it's already there immediately without waiting for the ECM/injectors to compensate.

You will never see more power in closed loop because, by definition, closed loop is part throttle, cruise condition. Keep your AFR targets in CL at 14.7.

AFR targets in OL are a different story. MFG's are not able to dump mass amounts of fuel into the engine (causing high CO) for acceleration because of the EPA. There LOTS of opinions on what targets to use, but around 13:1 is typically accepted for V-twin performance.

*this may be why you think it runs better with the AFV locked at 108%. The rich cylinder has extra (normally wasted out the tail pipe when cruising) fuel ready to be burned when you blip the throttle.

I'd still check the intake seals though.