You guys should look up the regulations and conclusions. Short story the perfect chemistry to reduce NOx is an airfuel ratio of 14.5. Explains the flat spot. Perfect air/fuel is 13.5 for your enhanced riding pleasure. Also the volume of the cat converter must be very large for any volume of exhaust. Can you say two exhaust pipes with a volume controlling valve (it's not for better mid-range torque). Wait there's more, euro IV regs for 2012 maybe by-passed for euroV regs. (dealers news). Now if the rain would stop I could go riding.