If you wish to do adjustments to your Derbi Atlantis Bullet then it is always recommended to have access to a Workshop Manual to keep just for a reference if you need to know ways to remove a particular component including Wheel and fit it again in the right way.
Derbi Atlantis Bullet Workshop Manuals will provide you with detailed diagnostic guides with regards to your car so if something is not working it can help you understand what the situation is and how to make it better. After that you can evaluate if this can be done yourself or if ever the job is too big you are able to make a reservation for your Atlantis Bullet into a trusted friendly mechanic.
Derbi Atlantis Bullet manual