Rebuild kit includes gaskets & O-rings for all 53 & 64 series Bing carburetors. Kits also available with diaphragms for the 64 series, Kits with diaphragms come with the throttle shaft butterfly screws.
This will help you figure out which carburetors your BMW 2Valve Boxer has,
26mm Bings on the R50/5, R60/5, R60/6 & R60/7
32mm Bings on R65, R65LS, R75/5, R75/6, R75/7, R80G/S, R80, R80/7, R80RT, R90/6, R100/7 &1988-1995 R100GS, R100RT, R100RS
40MM Bings on 1977-1984 R100S, R100RS, R100RT, R100S, R1OOCS & R100T
38MM PHM Dellorto's on the R90S