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· Registered
58 Posts
Discussion Starter · #1 ·
Does anyone have the factory specs jetting for the Weber 40s that were fitted to the 2000GT Veloce (10521)?
Can the venturis/barrels be increased to 34mm? What effect would this venture change have on the overall jetting. I believe the normal venturi/barrel size is 32mm. I'd like the engine to breathe better without going to Weber 45ers.
The engine is not tuned. I believe my ports are polished and I just have electronic ignition.
Any info would be appreciated.

· Trained (ex)Professional, , 1953-2018 RIP
16,230 Posts
AFAIK, the 105.21 was fitted with either Solex or Dellorto, not Weber. But I prefer Webers anyway probably because of having no experience with the S or D sidedrafts. Anyway, I have a set of 40 DCOE 32, as fitted to a stock 1750, with stock jetting, on a modified 2l and it runs GREAT. Stock 1750 jetting is;

Main - 125
Air - 200
Emulsion tube - F9
Idle - 50F14
Accelerator - 35
Venturi - 32

A great write up on the selection and tuning of Webers can be found at
The 40DCOEs will accept up to a 36mm venturi. I'm toying with going to 36s myself and think a good starting point would be to change the mains to 145 and the E-tubes to F2.
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