Weber carburetors are wonderful because they are almost infinitely adjustable, allowing you to tune them to almost any engine need. Weber carburetors are terrible because they are almost infinitely adjustable, making it very easy to tune them poorly.
The appropriate tuning for a particular engine will vary depending on user preferences as well as mechanical characteristics like compression ratio, cam profiles exhaust design, etc.
Weber Carburettors* (Haynes,1979) and Weber Carburetors* (P. Braden, HP Books, 1988) both offer tuning recommendations for the TR6. These should only be considered approximations, starting points your own tuning activities.
suggested by HP:
model - 40DCOE18
main venturi - 30
aux. venturi – 4.5
main jet – 1.20
emulsion tube – F11
air corrector jet – 1.60
idle jet – 0.50F11
accelerator pump jet – 0.40
acc. pump orifice – 0.50
needle velve - n/a
suggested by Haynes:
model - 40DCOE20
main venturi - 27
aux. venturi – 4.5
main jet – 1.30
emulsion tube – F2
air corrector jet – 1.60
idle jet – 0.50F11
accelerator pump jet – 0.45
acc. pump orifice – closed
needle velve – 2.0
PC.
* yes they spell carburetor/carburetor in the titles differently, HP is American, Haynes is British.