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 canisterRemoval of the front wheel
Support the bike so that the front wheel is raised from the ground.
Remove the front brake calliper (b) by unscrewing the two screws (a) securing
the calliper to the fork leg; do not
disconnect the calliper from the hose.
Warning
Do not operate the brake lever when the callipers are ...
Checking engine oil level
Check the engine oil level through the sight glass (1) on the
clutch cover. When checking oil level, the motorcycle should
be perfectly upright and the engine cold. The oil level should
be between the two marks next to the sight glass. If level is
low, top up with shell advance ultra 4 engine oi ...
Removal of the primary drive gear
Withdraw the clutch housing (1) complete with driven gear of the primary pair
(a).
Remove the inner spacer (2).
Remove the oil pump (d) (sect. 9 - 2.1, Removal of the oil pump).
Lock the primary pinion (b) with the holding tool 88713.3417 And loosen the
threaded ring nut (3) u ...