Bold reference numbers in this section identify parts not shown in the figures alongside the text, but which can be found in the exploded view diagram.

This model is fitted with “three-way” catalytic converters. Catalytic converters are fitted to the exhaust system in order to elim­inate the noxious substances found in exhaust fumes, namely CO (carbon monoxide), HC (unburnt hydrocarbons) and NOx (nitric oxide). The catalytic converter has a special honeycomb support, coated with aluminium oxide, which creates an irregular surface thus increasing the surface area exposed to exhaust gas. The aluminium oxide is coated with activated substances that help to remove harmful components of exhaust emissions. These substances are usually platinum and rhodium. Platinum allows the oxidation (combination with oxygen) of CO and HC. Rhodium allows the reduction (combination with CO) of NOx contents.
To ensure that CO and HC components can oxidise to form water and carbon dioxide and that NOx contents can be reduced by forming nitrogen and carbon dioxide, there must be a precise amount of oxygen in the exhaust gas. For this reason it is essential that the air-fuel mixture is correctly proportioned. This result has been achieved thanks to the use of a sophisticated fuel system designed to meter the air-fuel mixture with absolute precision.

The lambda sensor (Sect. M 3) monitors the oxygen content of exhaust fumes and transmits the relative data instantaneously to the ECU. The control unit (through injection) keeps the air-fuel ratio as close as possible to optimum value (with a certain toler­ance) in order to ensure top performance of the catalytic converters in the exhaust pipes. In terms of emissions, this means achieving minimum hydrocarbon (HC) and carbon monoxide (CO) emissions as well as minimum nitrogen oxide (NOX) emissions. The 3 way catalytic converters complete the exhaust fumes cleaning process by converting residues of CO, HC and NOX in the exhaust gas, thus ensuring exhaust emissions comply with EURO 3 regulations.

In order to function correctly, the catalytic converter must reach a temperature of around 800 °C and never fall below 300 °C. The indicated maximum temperature must not be exceeded, otherwise the catalytic converter could be irreparably damaged. For this reason, it is essential that significant quantities of unburnt fuel do not accumulate in the exhaust gas post-treatment el­ement, since these would otherwise burn resulting in a sharp increase in temperature. This is why the ignition-injection system should always be in perfect working order (misfiring is not acceptable). Moreover, never push-start the motorcycle (with key and ENGINE STOP button set to ON). In this instance, if the engine does not start, any unburnt fuel would enter the exhaust system and stay in the catalytic converters. Motorcycles fitted with catalytic converters must be used exclusively with unleaded petrol. Otherwise the lead content of petrol would deposit on the activated substances and limit their action against the harmful com­ponents of exhaust gas.

Remove the left-hand side heat shield (33) loosening screws (26), (42) and (41); recover the spacers (45), (44) and the washers (34).

Follow the same procedure to remove the RH silencer (7).

Remove the protection (35), unscrewing the screw (26) and recovering the washers (34) and corresponding spacer (25).

Loosen the screws (15), keeping washers (38), to remove the exhaust valve motor (37) from the rear protection plate and discon­nect wiring (D).

Disconnect the two lambda sensors (2) from the main wiring harness (Sect. P 1, Routing of wiring on frame). Refer to Section M 3, Lambda sensor for details on lambda sensor.

Unscrew the clamp (16) and separate the centre exhaust pipe (5) from the horizontal cylinder exhaust pipe (3) and the vertical cylinder exhaust pipe (4).

Slide out horizontal exhaust pipe (3) from vertical head; recover the gasket (1).

Remove the vertical exhaust pipe (4) from the vertical cylinder head, recovering the gasket (1).

Undo the screws (26) and remove the horizontal heat shield (13); recover the spacers (25) and the washers (34).

Renew the gaskets (1).

Tighten the nuts (9) fastening the flanges to the heads to the specified torque (Sect. C 3, Frame torque settings).

Check that the quick-release fasteners (32) are installed on the horizontal cylinder exhaust pipe (3).

Refit the horizontal heat shield (13) securing it with the retaining screws (26), the spacers (25) and the washers (34).

Tighten the screws (26) to the specified torque (Sect. C 3, Frame torque settings).

Fasten the vertical head exhaust pipe (5) to engine and tighten screw (15) to the specified torque (Sect. C 3, Frame torque set­tings).

Insert the centre exhaust pipe (5) in the horizontal cylinder exhaust pipe (3) and vertical cylinder exhaust pipe (4) and secure with the clamps (16).

Position the clamps (16) so they are flush with the end of the exhaust pipes, or at least so that the notches (B) are not completely uncovered.

Tighten the clamps (16) to the specified torque (Sect. C 3, Frame torque settings).

Connect the wiring (D) to the main wiring harness (Sect. P 1, Routing of wiring on frame).

Adjust cable (36) on exhaust valve and exhaust valve motor as explained under Sect. D 4, Adjusting the exhaust valve bowden cable.

Set the exhaust valve motor (37) onto rear protection plate, paying attention to position the spring (F) as shown. Insert the fixing screws (15) with washers (38). Tighten the screws (15) to the specified torque (Sect. C 3, Frame torque settings).

Fasten wiring (D) to exhaust valve motor central body using the rubber tie (39) and ensuring that the cables coming out of motor do not touch the metal sheet sharp edge.

Fasten the central exhaust pipe (5) to the mounting bracket of tank and exhaust (E) tightening nuts (20) to the specified torque (Sect. C 3, Frame torque settings).

Connect the lambda sensors (2) to the main wiring harness (Sect. P 1, Routing of wiring on frame).

Tighten the screw (30) to the specified torque (Sect. C 3, Frame torque settings) while holding nut (30).

Check that the quick-release fasteners (32) are installed on the LH silencer (8).

Fit the left-hand side heat shield (33) and install, in-between heat shield and exhaust silencer (8), the three washers (34) and spac­ers (44) (25) and (45), as shown below.

Tighten the screws (42), (26) and (41) to the specified torque (Sect. C 3, Frame torque settings).

Follow the same procedure to refit the RH silencer (7).