Two PCSOs saw the modified bicycle and its rider on Snapethorpe Road in Lupset while searching for a nuisance quad biker.
On closer inspection, they found the bicycle had been fitted with a small engine.
It was seized because the male biker had no licence. There was also no registration mark on the vehicle, tax or MOT.
The police said: "The vehicle was surrendered at the roadside by the owner whose details will be forwarded for reporting for the offences.
"The vehicle, which was not safe, will be unclaimed and destroyed."
This article was first published by the Wakefield Express.