If you choose to execute fixes for your Jawa 350 then it is always a good plan to have a Workshop Manual to use as reference in case that you need to know tips to take out a particular component for example Drive Shaft and install it again in the correct manner.
Jawa 350 Workshop Manuals offers clear unique diagnostic info for your car or truck therefore if something is broken it can help you understand what the issue is and how to repair it. After that you can decide if this can be achieved yourself or if the job is just too big you can book your 350 in with a local mechanic.
Jawa 350 manual