Option 1: Have another, separate bung welded on for the wide-band sensor.
Option 2: Some wide-band sensor drivers have the capability of emulating a standard narrow-band sensor output. Do that, and wire that output to the existing wiring for the standard sensor.
Option 3: Some tuning packages come with wiring/software to eliminate the standard sensor. I do not know if these "play nice" with the vehicle on-board diagnostics. Theoretically, they *shouldn't* play nice with OBD, but bike OBD is currently nowhere near as sophisticated as automotive OBD.
