Usa models are equipped with an additional system with an evaporative emissions canister that prevents fuel fumes from being discharged into the atmosphere.
The breather hose (4) is connected to the canister filter (1); when the fuel has been filtered, it is returned through the hose (2) to the horizontal (a) and vertical (b) intake manifolds via the hoses (2a) and (2b). Drainage pipe (c) and the hose (5) vent to the ground.
For correct positioning of the connection hoses consult the indications given below.

Evaporative emissions canister
Removal of the evaporative emissions canisterLimitations
This emission control system warranty shall not cover any
of the following:
Repair or replacement required as a result of
Accident,
Misuse,
Repairs improperly performed or replacements improperly
installed,
Use of replacement parts or accessories not conforming
to ducati specifi ...
Routine maintenance record
...
Timing system
Central external cover
Air filter
Horizontal cylinder timing belt cover
Screw
Filter support
Screw
Washer
Nut
Tensioner pulley assembly
Circlip
Camshaft pulley
Tensioner pin
Idler pulley assembly
Timing belt
Nut
Key
Spacer
Camshaft pulley
Driveshaft pulley ...