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 canisterOverhauling the rear swingarm
Inside the swingarm (8), in correspondence with the pivot point on the frame,
there is a pair of ball bearings (10) and a
spacer (11) on the rh side, and a pair of roller bearings (6), with sealing
rings (5), on the lh side.
To change the bearings, proceed as follows.
Remove the shims ( ...
Clutch cover
Clutch-side crankcase cover
Screw
Screw
Oil level sight glass
Screw
Plate
Bush
Sealing ring
Shim washer
Circlip
O-ring
Locating bush
O-ring
Plug
Sealing washer
Screw
Plug
Panel
Spare parts catalogue
Diavel abs clutch-side crankcase cover
Diavel carbon
a ...
Refitting the crankshaft/connecting rod assembly
Install the connecting rod assembly (6) and (2) in the crankcase, carry out
the shimming and crankcase half reassembly
procedure as described in sect. 9 - 9.2, Reassembly of the crankcase halves.
Important
Make sure that the connecting rods (2) are correctly positioned in the
cylinders. Incor ...