Since the local Vespa service dealer in my area does not service vintage Vespas, I have found the Internet to be a must in trying to restore my '64 150. I have used several sources: eBay, ScooterPartsDirect.com, and scomo.net are a few I have tried for various parts.
However, my favorite source for parts -- and online advice -- is ScooterWorks.com
. They have not only supplied me with parts at a good price, they have also helped me make sure that I was getting the right parts. The same people you talk with to order your parts are the ones who can tell you how those parts work on your bike.
Thanks, ScooterWorks.com. I hope you don't mind me making you the unofficial parts supplier for Vespatude.com.