Harley Davidson noise

[Wags]

Try talking to them first, maybe there's some sort of accommodation you can reach without bringing in the authorities. Its a drag to have bad blood with the neighbors regardless of who's at fault. If that doesn't work there's probably some agency in the city that will mediate the dispute. Escalate your response a little at a time, but talk to the riders first. Best not to call the police first thing for a relatively minor issue - at least that's probably how the police will see it. You never know when you need the police for something serious.