The teen, who cannot be identified, appeared at Wigan Youth Court facing accusations of stealing a £900 Kawasaki on October 14 and to fencing another of the same make - worth £7,500 - plus a £900 Honda and stolen registration plates on November 5.
The boy also admitted to trying to steal a pedal cycle from Wigan North Western Station on July 13 and to threatening a PCSO on September 16.
Sentencing is on June 16.