8 - | Exhaust system

1 | Exhaust gasket

2 | Lambda sensor

3 | Horizontal cylinder head exhaust pipe

4 | Vertical cylinder head exhaust pipe

5 | Centre exhaust pipe

6 | Lower bracket

7 | Right-hand silencer

8 | Left-hand silencer

9 | Nut

10 | Spring

11 | Screw

12 | RH heat shield

13 | Horizontal heat shield

14 | Rubber mounting

15 | Screw

16 | Clamp

17 | Spacer

18 | Plug

19 | Sealing washer

20 | Special nut

21 | Right-hand bracket

22 | Left-hand bracket

23 | Bush

24 | Rubber

25 | Spacer

26 | Screw

27 | RH silencer support bracket

28 | LH silencer support bracket

29 | Screw

30 | Screw

31 | Nut

32 | Quick-release fastener

33 | LH heat shield

34 | Washers

Parts catalogue

Exhaust SySTEM

Important
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.
Operating principle of the catalytic converter
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. To ensure that the catalytic converters in the exhaust system work efficiently, the ECU controls fuel injection to maintain the air/fuel ratio within a tolerance close to the optimal value, achieving the minimum possible emissions of hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxide (NOx). 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.
How to ensure that the catalytic converter functions correctly
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, the motorcycle should never be pushed with the ignition key and ENGINE STOP button set to ON. In this case, in fact, if the engine fails to start, the unburnt fuel will enter the exhaust system and deposit 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.
Removal of the exhaust system

Operation | Section reference
Remove the RH footrest bracket | H 4, Removal of the footrest brackets

Remove the retaining spring (10) of the LH silencer (8) from the centre exhaust pipe (5).
While counterholding the nut (31), unscrew the retaining screw (30) and remove the LH silencer (8) from the motorcycle.
Recover the spacer (23) and the rubber bushes (24).
Remove the LH heat shield (33) by unscrewing the retaining screws (26) and recover the spacers (25) and the washers (34).
Follow the same procedure to remove the RH silencer (7).
Unscrew the two nuts (20) and release the centre exhaust pipe (5) from the fuel tank support bracket and exhaust (A).
Disconnect the two lambda sensors (2) from the main wiring harness (Sect. P 1, Routing of wiring on frame). For details on the lambda sensor, refer to Sect. M 3, Lambda sensor.
Unscrew the screw (15) securing the centre exhaust pipe (5) to the engine.
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).
Loosen and remove the nuts (9) securing the exhaust pipe flanges to the cylinder heads.
Remove the flanges from the cylinder heads.
Remove the horizontal cylinder exhaust pipe (3) from the horizontal cylinder head, recovering the gasket (1).
Remove the vertical exhaust pipe (4) from the vertical cylinder head, recovering the gasket (1).
Important
Block off the exhaust ports on the head to prevent foreign matter from entering the combustion chamber.
Remove the horizontal heat shield (13) by unscrewing the retaining screws (26) and recover the spacers (25) and the washers (34).
Refitting the exhaust system
Renew the gaskets (1).
Refit the horizontal cylinder exhaust pipe (3) and the vertical cylinder exhaust pipe (4) to the respective cylinder heads.
Tighten the flange nuts (9) 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).
Fit the vertical cylinder exhaust pipe (3) to the engine and tighten the 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 as shown in the figure.
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).
Fix the centre exhaust pipe (5) to the fuel tank support bracket (A) by screwing on the nuts (20) and tightening them 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).
Connect the silencer (8) to the centre exhaust pipe (5) and locate the springs (10).
If removed, install the two rubber bushes (24), positioning on either side of the silencer bracket (27).
Insert the spacer (23) in the silencer support bracket (27).
Move the silencer support brackets so that they rest against the footrest brackets (A).
Insert the screw (30) and, on the opposite side, fit the nut (31).
Tighten the screw (30) to the specified torque (Sect. C 3, Frame torque settings) while counterholding the nut (30).
Check that the quick-release fasteners (32) are installed on the LH silencer (8).
Refit the LH heat shield (33) 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).
Follow the same procedure to refit the RH silencer (7).