Carburettor connecting piece kit for Mikuni carburettors

M42 screw-in intake manifold complete kit for use with Mikuni TM-36, TM-40, TM-42 flat-slide or VM-38 round-slide carburetors (originally present on R100 models)

This screw-in manifold kit fits all R80 and R100 models with M42 thread. The manifolds are required when using Mikuni TM-36, TM-40, TM-42 flat-slide or VM-38 round-slide carburetors on models with small intake manifolds (BMW R80, R80R models).
If the Mikuni carburetors are to be used on an R100, no conversion is necessary. These models already have the "large" screw-in manifold and the "large" rubber sleeve installed.  

How can I check this: The screw-in manifolds must have an outer diameter (carburetor side) of 52mm. If the diameter is smaller, this screw-in manifold kit is required.   

Price is per side, therefore 2 kits are required.