Ducati Monster 695 User Manual page 304

Exhaust system
19 LH bracket
20 Bush
21 Seal, thk.1
22 Spacer
23 Screw
24 Screw
25 Screw
26 Washer
27 Lambda sensor
Spare parts catalogue
Exhaust system
Caution
Bold reference numbers in this section identify parts shown in this exploded view diagram. These parts do not appear
in the figures near the text.
Catalytic converter operating principle
This model is fitted with "three-way" catalytic converters. They are fitted to the exhaust system in order to render
exhaust fumes harmless, especially CO (carbon monoxide), HC (unburnt hydrocarbons) and NOx (nitric oxide). The
catalytic converter has a special honeycomb support, coated with aluminium oxide, which makes surface rough, thus
offering a wider area to exhaust gas exposure. Aluminium oxide includes some activated substances helping reducing
harmful substances. Activated substances are usually platinum and rhodium. Platinum oxidizes (combines with
oxygen) CO and HC. Rhodium reduces (combines with CO) NOx. Exhaust gases must contain a certain quantity of
oxygen for CO and HC to be oxidized to create water and carbon dioxide and for NOx to be reduced into nitrogen and
carbon dioxide. This requires accurate air/fuel ratio control. Air-fuel mixture ratio is controlled by our sophisticated
fuel feeding system, which ensures top precision while dosing air-fuel mixture.
The lambda sensor (Sect. M 3) checks exhaust gas oxygen content and immediately outputs this information to the
control unit. To ensure utmost efficiency of the catalytic converters installed at the exhaust, the control unit controls
injection so that air/fuel ratio is maintained close to ideal value,within a certain tolerance, thus obtaining minimum
emissions of hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxide (NOX). 3-way catalytic converters then
complete exhaust gas cleaning procedure converting CO, HC and NOX residues thus ensuring that emissions comply
with EURO 2 standard.
Precautions for catalytic converter proper operation
In order to operate correctly, the catalytic converter must reach temperatures close to 800 °C and never less than
300 °C. However, exceeding the maximum temperature limit will irreparably damage the catalytic converter. For this
reason, exhaust gas post-treating device should never include high amounts of unburnt fuel which would cause high
temperature increase. This is why the ignition - injection system should always be in perfect operating conditions:
ignitions should never be failed. In addition, never push start the motorcycle forward with the ignition key and the
ENGINE STOP button set to ON. If the engine does not start, unburnt fuel will enter the exhaust system and get to
the catalysts. Motorcycles fitted with catalytic converters can only be filled with unleaded gasoline. Lead would settle
onto activated substances and limit their action against harmful substances in exhaust gas.
Removing the exhaust system
Loosen and remove the screws (11) securing the silencer brackets (13) and (19) to footpeg supports (A) on either
sides of the vehicle.
Collect nuts (15) and washers (14).
If necessary, remove the spacers (10) and rubber blocks (9) from footpegs plates and remove the bushes (20) from
the brackets (13) and (19).
Loosen the clamps (8) of the right (12) and left silencers (16).
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