Do I need to bring my own motorcycle?

No.  You would normally use one of ours.  We have 125cc motorcycles for CBT as well as 50cc and 125cc scooters.  We have 500cc bikes for A2 and 650cc for Category A.  You can use your own if you prefer but make sure it is fully road legal – taxed, insured, MoT if necessary, L plates front and rear.