Page 97 - 2019 SHOP MANUAL CRF1000/A/D

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MAINTENANCE
COOLING SYSTEM

Check the radiator air passages for clogging or
damage.
Straighten bent fins, and remove insects, mud or other
obstructions with compressed air or low water pressure.
Replace the radiator if the air flow is restricted over
more than 20% of the radiating surface.
Inspect the water hoses for cracks or deterioration, and
replace them if necessary.
Check the tightness of all water hose band screws
(page 8-8).

SECONDARY AIR SUPPLY SYSTEM

• This model is equipped built-in secondary air supply
system. The pulse secondary air supply system is
located on the cylinder head cover [1].
• The secondary air supply system introduces filtered
air into the exhaust gases in the exhaust port [2].
The secondary air is drawn into the exhaust port
whenever there is negative pressure pulse in the [4]
exhaust system. This charged secondary air
promotes burning of the unburned exhaust gases
and changes a considerable amount of [3]
hydrocarbons and carbon monoxide into relatively
harmless carbon dioxide and water. [1]
Remove the air cleaner housing (page 7-11).
Check the PAIR hoses for deterioration, damage or
loose connections.
Also, check that the hoses are not kinked, pinched or
cracked.
– Air suction hose [3] (between the air cleaner housing [2]
and PAIR control solenoid valve)
– Air supply hose [4] (between the PAIR control
solenoid valve and cylinder head cover)
If the air suction/supply hose show any signs of heat FRESH AIR
damage, inspect the PAIR reed valves (page 7-21). EXHAUST GUS
For secondary air supply system inspection (page 7-
18).

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