0796.38.630 also 0684.38.630 (079638630 also 068438630) - New 20/10 speedo drives for all 18" front wheel bevel drives with Veglia or Smiths instruments. This is a very nicely manufactured reproduction unit.
Order it by itself or also get a new stainless steel washer that goes between the inside of your fork leg and the speedo drive.
*NOTE: The long tab will fit ALL wheel applications on bevel drive twins but you must trim the length of the tab so that it doesn't bottom out inside your specific wheel..