I imagine that is why we don't see a factory bike with a 120"or a 124" since it would be hard to meet EPA regulations.
I agree that H-D can and will meet EPA regulations and still offer performance but I bet it will come at a price. Mainly an engine rediesign such as a V-rod type configuration for the softails and touring bikes.
Our Air-cooled v-twin may be on it's last legs if the government has it's way.
I know if H-D develops a large V-rod type engine it could out-perform what we have now but it won't be the same. Those of you old enough to remember the muscle car era will always remember the sound of a loping big block.The newer cars can out-perform those old cars but they don't have the soul.
Just like the article in Cycle World magazine, the Goldwing out-performs the Harley in speed and power but how many of us will trade for one?