Troubleshooting - Honda 2009 CRF450X Owner's Manual & Competition Handbook

Troubleshooting

The items that are serviceable using this Manual
are followed by the page number reference in
parenthesis. The items that require use of the
Honda Shop Manual are followed by an
asterisk(*).
ENGINE DOES NOT START OR IS HARD TO START
CHECK POSSIBLE CAUSES
1. Check the fuel NOT REACHING • No fuel in fuel tank
• Clogged fuel line or
flow to carburetor CARBURETOR
fuel filter (P.41)
REACHING
• Sticking float valve*
CARBURETOR
• Clogged fuel fill cap
breather tube (P.40)
2. Try spark test* WEAK OR NO • Faulty spark plug (P.60)
SPARK • Fouled spark plug (P.60)
GOOD SPARK
• Faulty ignition control
module*
• Broken or shorted spark
plug wire
• Faulty exciter coil*
• Broken or shorted ignition
coil
• Faulty engine stop button
• Loose or disconnected
ignition system wires
• Faulty ignition pulse
generator*
3. Test cylinder
LOW • Valve stuck open
compression*
• Worn cylinder and piston
ring*
CORRECT
• Leaking/damaged
cylinder head gasket
• Improper valve timing*
• Seized valve
4. Start by following
ENGINE STARTS • Improper choke operation
normal starting • Pilot screw incorrectly
BUT SOON STOPS
procedure
adjusted*
• Insulator leaking
ENGINE DOES
• Improper ignition timing
NOT FIRE
(Faulty ignition coil or
ignition pulse generator)*
• Fuel contaminated
• Improper hot start
operation (P.59)
5. Remove and
WET PLUG • Carburetor flooded
inspect spark plug • Choke closed
• Throttle valve open
DRY
• Air cleaner dirty (P.50)
6. START WITH CHOKE ON
152
Tips
HONDA O/M CRF450X (Eu) 3RMEY620 00X3R-MEY-6200
POOR PERFORMANCE AT LOW AND UNSTABLE
IDLE SPEED
CHECK POSSIBLE CAUSES
1. Check if air INCORRECT • Over-oiled air cleaner
cleaner is over-
oiled (P.50)
CORRECT
2. Check if the
LEAKING • Loose connecting tube
connecting tube
and/or insulator band
and/or insulator
• Damaged connecting
is leaking
tube and/or insulator
NOT LEAKING
3. Check carburetor INCORRECT • Improper pilot screw
adjustment*
pilot screw
adjustment*
CORRECT
4. Check carburetor CLOGGED • Contaminants in the
jets and accelerator fuel
pump for clogs • Not cleaned frequently
enough (P.137)
NOT CLOGGED
5. Try spark test* WAKE OR • Faulty, carbon or wet
INTERMITTENT fouled spark plug (P.60)
GOOD SPARK
SPARK • Faulty ignition control
module*
• Faulty exciter coil*
• Faulty ignition coil*
• Broken or shorted
spark plug wire
• Faulty ignition pulse
generator*
• Loose or disconnected
ignition system wires
• Faulty engine stop
button
6. Check the throttle INCORRECT • Faulty throttle position
position sensor* sensor*
CORRECT
• Ring worn
7. Test cylinder LOW
low compression* • Cylinder worn or
damaged*
CORRECT
• Piston worn or
damaged*
• Head gasket not
sealing
• Valve stuck open
POOR PERFORMANCE AT HIGH SPEED
CHECK POSSIBLE CAUSES
1. Disconnect fuel FUEL FLOW • Lack of fuel in tank
(P.40)
line at carburetor RESTRICTED
• Clogged fuel line
and check for
clogging (P.40) (P.40)
• Clogged fuel fill
UNRESTRICTED
cap breather tube
FUEL FLOW
(P.40)
• Clogged fuel valve
(P.40)
• Clogged fuel filter
(P.41)
2. Remove air DIRTY • Not cleaned
cleaner (P.50) frequently enough
(P.50)
AIR CLEANER
NOT DIRTY
3. Check carburetor CLOGGED
• Contaminants in
jets for clogging the fuel
NOT CLOGGED
4. Check valve INCORRECT • Cam sprocket not
timing installed properly
CORRECT
5. Try spark test* WEAK OR
• Faulty, carbon or wet
INTERMITTENT fouled spark plug
GOOD SPARK
(P.60)
SPARK
• Faulty ignition control
module*
• Faulty exciter coil*
• Faulty ignition coil*
• Broken or shorted
spark plug wire
• Faulty ignition pulse
generator*
• Loose or disconnected
ignition system wires
• Faulty engine stop button
6. Test cylinder LOW • Ring worn
• Cylinder worn or
low compression*
damaged*
CORRECT
• Piston worn or
damaged*
• Head gasket not
sealing
• Improper valve timing*
• Valve stuck open