If you want to execute adjustments on your own Jawa 350 Type 6385 then it is usually recommended to have access to a Workshop Manual for reference in case you need to know proven methods to take off a certain component for instance the Gearbox and match it again in the correct way.
Jawa 350 Type 6385 Workshop Manuals can provide precise diagnostic wisdom for the vehicle so if something is broken it can help you find out what the issue is and methods to fix it. Then you are able to assess if you can do this by yourself or if the job is simply too big you can still make a reservation for your 350 Type 6385 in to a trusted repair garage.
Jawa 350 Type 6385 manual