As of January 19th 2013 the UK motorcycle licence options have changed.
If you wish to continue riding after your CBT 2 year duration or ride without L plates or to ride larger motorcycles you will need to pass a motorcycle theory test and appropriate motorcycle practical test. If you do not pass both parts of your practical test within 2 years of passing your theory test and whilst holding a valid CBT certificate you will need to start this process again.
Please be aware that if you held a motorcycle or moped licence prior to January 19th 2013 the rules are different. You can check these here.
If you wish to check the bikes that you can ride or the training that you will require to ride the bike you want you can do so here.