How does a unocycle / single wheel motorcycle work?

[GreenAce92]

I don't understand how one wheel could be ridden as a motorcycle, what would oppose the driving moment that rotates the tires?

http://3.bp.blogspot.com/_LnXKlTB8gKw/SGrzC8_L1-I/AAAAAAAAB04/Shkqgbqadx4/s400/unocycle_main.jpg

 

[rcgldr]

It's similar to balancing a broom upside down. The rider would have to initiate a lean in the desired direction of acceleration by initially accelerating in the "wrong" direction first, then begin the actual acceleration. A motorized unicycle would be difficult and somewhat hazardous to ride. There are motorcyclists that can do wheelstands (balanced wheelie) indefinately, but they have the option of dropping the front tire back down if needed.

 

[Rear Naked]

There is a gyroscope in it