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 canisterRefitting the engine
Refitting is the reverse of removal.
Important
Apply recommended grease and tighten the special screws (6) to a torque of
60 nm +/- 5% (sect. 3 - 3, Frame torque
settings).
Tighten the nuts (3) to a torque of 48 nm +/- 5% (sect. 3 - 3, Frame torque
settings).
Warning
For the assembly seque ...
Disassembly of gear interlock plunger and pawl assembly
Unscrew the interlock plunger screw (5) and remove the seal (6), spring (7)
and the detent ball (8).
Unscrew the clutch-side crankcase half screw (3) and remove the pawl (4),
washer (2) and spring (1).
...
Refitting the expansion tank
If the support (15) has been removed, place the hose clamps (14) on the
bracket (15) orienting them as indicated.
Fully press the pins (a) to block the clamps (14) until pins surfaces (b) are at
the same level of the clamps (14) surfaces.
Apply recommended threadlocker to the thread of the ...