Modern Vespa

I just got my first MP3 and I was wondering at 55 mph. It makes a rhythmic sound from the engine. The best I can describe it is, a vibration of the scooter in rhythm that keeps a perfect beat over and over. I'm sorry I don't know how to do any better describing it. Thanks

We're gonna need more details here, such as model year, miles on the vehicle, miles on the tires, age of the tires, age of the drivebelt system, etc, etc, etc.

Describe the vibration in details. Are you seeing vibration in the handlebars or any part of the bike???

Details is the key here

Otherwise we're just throwing darts blindfolded.

the audio /video file you posted can't be found

No vibration. I'm a newby, so I can't get a recording yet. I will be getting a phone mount in a couple weeks. I will see if I'm comfortable enough then. Thanks