Mounting the 15/15 Sha Dellorto carburetor with a shorty intake on a 50V.  The best way to mount the Sha 15/15 Dellorto carburetor on the Mobylette is to use the shorty intake (bottom right picture). The Dellorto will fit right on the shorty intake made for the 12 mm Gurtner carb. The advantage for the 50v models, it will not hit the bottom of the fuel tank when the engine is in the up position at full throttle. Also, there is no need to customize the throttle assembly, the slide will go all the way up and down with the stock grip, this is true for the 77/78/79/80 50L/50V/50VLX models . When ordering your Dellorto ,you must buy the carburetor with the handlebar choke type, not the manual choke mounted on the carburetor. You need to buy a number 57 jet size to 59, I like the 59 jet, it works fine with the stock filter and cover. You may want to experiment with different sizes depending on your elevation.                       You can also use the shorty from a 10mm Gurtner carburetor setup to install the15/15 Sha Dellorto on a B (25mph) Model 50V or any 50L&50 (25mph) models, you have to use the insert that comes off the 10mm Gurtner carburetor so the Dellorto will fit right on the 10 mm shorty. ps: On the non variated engine)50/50L/40/etc the long intake is fine, since the engine is stationary, with the variated engine the short intake is a perfect fit for the Dellorto, the carburetor does not hit the bottom of the tank when the engine is in the full throttle mode.