Honda 2004 CRF250X Service Manual

GENERAL INFORMATION
EXHAUST EMISSION CONTROL SYSTEM (PULSE SECONDARY AIR INJECTION SYSTEM):
'04 - '06 California type , After '06
The exhaust emission control system includes of a secondary air supply system which introduces filtered air into the
exhaust gases in the exhaust port. Fresh air is drawn into the exhaust port whenever there is a negative pressure pulse in
the exhaust system. This charge
of fresh ai r promotes burning of the unburned exhaust gases and changes a considerable
amount of hydrocarbons and carbon monoxide into relatively harmless carbon dioxide and water vapor.
This model has a pulse secondary air injection (PAIR) control valve. A PAIR check valve prevents reverse air flow through
the system. The PAIR control valve reacts to high intake manifold vacuum and will cut off the supply of fresh air during
engine deceleration, thereby preventing afterburn in the exhaust system.
No
adjustment to the PAIR system should be made, although periodic inspection of the components is recommended.
PAIR COI'!T"OLVALVE
AIR CLEAN""
VACUUM HOSE
~ FRESH AIR
_ EXHAUST GAS
1-34

Honda 2004 CRF250X Specifications

General

Engine Type	249cc liquid-cooled single-cylinder four-stroke
Bore x Stroke	78.0mm x 52.2mm
Compression Ratio	12.5:1
Induction	Keihin 37mm flat-slide carburetor
Transmission	5-speed
Final Drive	O-ring-sealed chain
Front Suspension	47mm inverted Showa cartridge fork with 16-position rebound and 16-position compression damping adjustability; 12.4 inches travel
Rear Suspension	Pro-Link Showa single shock with spring preload, 17-position rebound damping adjustability, and compression damping adjustment separated into low-speed (13 positions) and high-speed (3.5 turns); 12.4 inches travel
Front Brake	Single 240mm disc with twin-piston caliper
Rear Brake	Single 240mm disc
Front Tire	80/100-21
Rear Tire	100/100-18
Rake (Caster Angle)	27.5°
Trail	113mm (4.4 inches)
Wheelbase	58.3 inches
Seat Height	37.7 inches
Ground Clearance	13.4 inches
Ignition	CD with electronic advance