This 26mm-28mm Mikuni carb adapter is used with the stock flange mount intakes that were fitted to early Alpina, Sherpa T, Sherpa S 100, Lobito etc. that were originally using the 22mm, 25mm & 27mm round body Amals . Remove the spacer block and 2 studs from the stock intake, then with the 2 screws, a little bit of RTV silicone on the mounting surface, you can bolt up this mount for an easy conversion to fit a 26mm-28mm round slide or 28mm flat slide Mikuni carburetor.