If you want to undertake adjustments to your Vespa ET4 50 then it is always recommended to have a Workshop Manual to use as personal reference in the event that you need to know the way to take out a certain part for instance the Clutch and fit it again successfully.
Vespa ET4 50 Workshop Manuals offers clear precise diagnostic facts for your car so if something is wrong it can help you figure out what the situation is and easy methods to resolve it. After that you can decide if this can be achieved yourself or if the job is simply too big you are able to make a reservation for your ET4 50 in to a decent repair garage.
Vespa ET4 50 manual