If you choose to execute repairs on your Sym Joyride 150 then it will always be a great idea to have a Workshop Manual to use as personal reference if you want to know how you can remove a specific component including Gearbox and fit it again the right way.
Sym Joyride 150 Workshop Manuals can provide detailed diagnostic info for your car so if something is playing up it will help you understand what the situation is and how you can correct it. Then you are able to decide if this can be done by yourself or if ever the job is just too big you can make a booking for your Joyride 150 into a decent repair garage.
Sym Joyride 150 manual