Troubleshooting - Honda CRF150R 2020 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 Service Manual are followed by an asterisk
*
( ).
ENGINE DOES NOT START OR IS HARD TO START
CHECK POSSIBLE CAUSES
1. Check the fuel flow NOT • No fuel in fuel tank
to carburetor REACHING • Clogged fuel line or fuel
CARBURETOR filter (P.34)
REACHING
• Sticking float valve
CARBURETOR
• Clogged fuel fill cap
breather tube
WEAK OR
2. Try spark test * • Faulty spark plug (P.52)
NO SPARK
• Fouled spark plug (P.52)
GOOD SPARK
• Faulty ignition control
module
• Broken or shorted direct
ignition coil wire
• Faulty exciter coil
• Broken or shorted direct
ignition coil
• Faulty engine stop button
• Loose or disconnected
ignition system wires
• Faulty ignition pulse
generator
LOW
3. Test cylinder • Valve stuck open
compression * • Worn cylinder and piston
ring
NORMAL
• Leaking/damaged
cylinder head gasket
• Improper valve timing
• Seized valve
4. Start by following ENGINE • Improper choke operation
normal starting STARTS • Pilot screw incorrectly
procedure BUT SOON adjusted
STOPS • Insulator leaking
ENGINE DOES
• Improper ignition timing
NOT FIRE
(Faulty direct ignition coil
or ignition pulse
generator)
• Fuel contaminated
• Improper hot start
operation (P. 13)
5. Remove and WET PLUG • Carburetor flooded
inspect spark plug • Choke closed
• Throttle valve open
DRY
• Air cleaner dirty (P. 43)
6. START WITH CHOKE ON
POOR PERFORMANCE AT LOW AND UNSTABLE
IDLE SPEED
CHECK
1. Check if air cleaner
is overoiled (P.43)
CORRECT
2. Check if the
connecting tube
and/or insulator is
*
leaking
NOT LEAKING
3. Check carburetor
pilot screw
adjustment
*
CORRECT
*
4. Check carburetor
jets and accelerator
*
pump for clogs
NOT CLOGGED
*
5. Try spark test
*
GOOD SPARK
*
*
6. Check the throttle
*
position sensor
CORRECT
7. Test cylinder
compression *
CORRECT
POSSIBLE CAUSES
INCORRECT
• Over-oiled air cleaner
LEAKING • Loose connecting tube
and/or insulator band
• Damaged connecting
tube and/or insulator
INCORRECT • Fuel-air mixture too lean
(Turn the pilot screw out)
(P.120)
• Fuel-air mixture too rich
(Turn the pilot screw in)
(P. 120)
CLOGGED
• Contaminants in the fuel
• Not cleaned frequently
enough (P.112)
WEAK OR
• Faulty, carbon or wet
INTERMITTENT
fouled spark plug (P.52)
SPARK
• Faulty ignition control
module *
• Faulty exciter coil *
• Faulty engine stop button
• Faulty direct ignition coil
• Broken or shorted direct
ignition coil wire
• Loose or disconnected
ignition system wires
• Faulty ignition pulse
generator *
INCORRECT • Faulty throttle position
* sensor *
LOW • Ring worn
• Cylinder worn or
damaged *
• Piston worn or damaged
• Head gasket not sealing
• Valve stuck open

Troubleshooting

POOR PERFORMANCE AT HIGH SPEED
CHECK
1. Disconnect fuel line FUEL FLOW
at carburetor and RESTRICTED
check for clogging
(P.34)
UNRESTRICTED
FUEL FLOW
DIRTY
2. Remove air cleaner
(P.43)
AIR FILTER
NOT DIRTY
CONDITION
3. Install a larger
WORSE
carburetor main jet
(P. 117)
CORRECT
4. Check carburetor CLOGGED
jets for clogging
NOT CLOGGED
5. Check valve timing INCORRECT
CORRECT
6. Try spark test WEAK OR
*
INTERMITTENT
GOOD SPARK
SPARK
7. Test cylinder LOW
compression *
CORRECT
*
POSSIBLE CAUSES
• Lack of fuel in tank (P.34)
• Clogged fuel line (P.34)
• Clogged fuel fill cap
breather tube (P.34)
• Clogged fuel filter (P.35)
• Clogged fuel valve (P.34)
• Not cleaned frequently
enough (P.43)
• Jet size wrong, rejet in the
opposite direction (P.120)
• Contaminants in the fuel
• Cam sprocket not
installed properly
• Faulty, carbon or wet
fouled spark pulg (P.52)
• Faulty ignition control
module *
• Faulty exciter coil *
• Faulty engine stop button
• Faulty direct ignition coil *
• Broken or shorted direct
ignition coil wire
• Loose or disconnected
ignition system wires
• Faulty ignition pulse
generator *
• Ring worn
• Cylinder worn or
damaged
• Piston worn or damaged
• Head gasket not sealing
• Valve stuck open
131
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