No this isn't legal
I'm not sure why everyone is in an uproar about this. No, this isnt legal and will not hold up in court. It is illegal to bar a legally registered vehicle from any road that has used state or federal dollars for construction or maintenance. If North Port, FL were a private community with locally built roads it would be legal. The exception for this law is for commercial vehicles. Of course laws can change and we as motorcyclist arent helping ourselves.
As others have noted, there is a reason that the local population as taken the effort to attempt to ban motorcycles from their community. This is most likely due to too many arm chap wearing Hells Angels wannabes with straight pipes and their counterparts the Stunt BoyZ wannabes with race cans. At least this is the most common complaint I hear from non-riders and riders alike.
Even as someone that commutes everyday on a motorcycle, Ive started to become increasingly annoyed with my fellow motorcyclists. Some examples:
This past 4th of July my family went to Washington, DC. While is the area we went to Gettysburg National Battlefield. It just so happens that that week was Gettysburgs "Bike Week". There was no a single place on that battlefield (which is multiple square miles is size BTW) that we didnt hear the roar of straight piped motorcycles. While we were in town, you couldnt walk down the street and carry on a conversation because the motorcycles were so loud that you couldnt hear the person next to you.
I live by the Smoky Mountain National Park and hike there quite often. However, on weekends, even when hiking miles off the main roads, I hear motorcycles every couple of minutes. Notice, I didnt say that I hear traffic, I said I hear MOTORCYCLES. From miles away, I hear the distinct "Potato-Potato" from the straight pipes of Harleys and their clones and the high-pitched whine of sportbikes with race cans.
Race cans belong on the racetrack and straight pipes in the scrap yard. There is no reason to pull off stock pipes to put on annoying and illegal aftermarket exhausts. Lets stop pissing people off before they legislate us out of existence.