Recently purchased vance and Hines hi output 2 into 1 stainless exhaust. V & H provide a 18mm quick tuning bungs facing outward on the exhaust. The 12 mm bungs face inward down low before the collector. I have a 09 Road King with 18mm O2 sensors. Is there a 2 wire 12mm O2 sensor that I can replace the 09 sensors with.... The plan is to replace the 96 cu in with a 120 cu in.

 

Wrong pipe. For an 09, the bung MUST be right near the exhaust valve. What matters is the WHEN, during the combustion process, the sensor is read by the ECM. Moving the bungs down to the bottom won't work right because the ECM will 'think' it is reading at the head. When all the while it WOULD be reading exhaust from the 'past'.

Take the pipe and have bungs welded in at the exhaust ports.