High speed low current motor selection and application (ultrasonic)

One of my bigger hobbies is restoring older motorcycles and one of the biggest problems with them is dirty carbs. They can be very difficult to clean and quite a hassle. I came up with an idea to make my own ultrasonic parts cleaner but I need help selecting the motor to help make it ultrasonic.

What I need is a small motor that spins at around 20,000 rpm that I could attach a form of plunger that will stick into the cleaning solution and agitate it at high frequency.

Since I just need to turn it on and off, does anyone have a solution on how to do this? I was thinking just going 120V -> 12v (or 24v) transformer -> rectifier -> motor

20,000rpm isn't remotely ultrasonic (333Hz) - unless you are trying to get cavitation?

These mist makers are very cheap, ultrasonic mist maker for sale | eBay
But they are dangerous, don't put your hand in the fluid if they are on.