By way of example - How would you feel if your next door neighbor had a smelting plant or burned dead animal bodies and directed the smoke across your property? Backyard BBQs wouldn't be much fun, would they? MMMMMM That burger sure tastes great while you're smelling the fat render out of a pile of dead animals. Well, backyard BBQs also aren't much fun when the guy next door is blasting his loud motorcycle into your property so no one can enjoy conversation, the sounds of nature, or even a little nice music. Most states, counties and cities address this with laws and ordinances. Even without those, the "common law" applies -- Even if there is no specific ordinance about loud motorcycles, loud noise coming from your property may constitute what the law calls a "nuisance." The property owner will have the responsibility to curtail, abate or remove the nuisance or will be liable to those affected by it. Generally this liability is measured by the diminution of the property values of the neighboring properties, or the neighbors' costs to abate the nuisance. It seems like a muffler would be cheaper than paying all of your neighbors for a drop in property values. There are also plenty of places to ride bikes which are not in the middle of a neighborhood. You have freedom to use your property, but your neighbors have a similar freedom to use theirs - and noise pollution interferes with their ability to use their property as they see fit. Perhaps the neighbor is a jerk because he approached you in an agitated state and was unpleasant. But have you stopped to think that perhaps you're a jerk because you are imposing the unpleasant aspects of your hobby on everyone in the vicinity?