Honda CRF450R 2020, Owner'S Manual & Competition Handbook

Page: 170 / 199

Troubleshooting
(cont’d)
Tips
165
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
official Honda Service Manual are followed by an
asterisk (*).
ENGINE DOES NOT START OR IS HARD TO START
Operate the start button with the throttle grip in
fully closed position (page 17).
CHECK POSSIBLE CAUSES
1. Check the starter
motor*
• Loose or disconnected
battery terminals (P.135)
• Blown main fuse (P.168)
• Weak battery (P.135, 169)
• Faulty starter relay switch
or starter motor*
• Faulty start button*
• Faulty clutch switch
• Faulty CKP sensor*
2. Check the starter/
ignition relay*
• Faulty starter/ignition
relay
3. Check the spark
plug condition
(P.78)
• Incorrect spark plug heat
range
• Incorrect spark plug gap
• Dirty air cleaner element
4. Try spark test* • Faulty spark plug (P.78)
• Fouled spark plug (P.78)
• Faulty ECM*
• Broken or shorted spark
plug wire
• Faulty alternator*
• Faulty ignition coil*
• Faulty engine stop
button*
• Loose or disconnected
ignition system wires
• Faulty CKP sensor*
• Faulty regulator/rectifier*
5. Check the PGM-FI
system (P.7)
• Faulty PGM-FI system
(P.9)
6. Check the fuel
pump operation
and inspect the fuel
flow*
• Faulty fuel pump*
• Clogged fuel pump filter
TURN
DOES NOT
TURN
CORRECT
INCORRECT
CORRECT
INCORRECT
GOOD SPARK
WEAK OR
NO SPARK
CORRECT
INCORRECT
CORRECT
INCORRECT
7. Check the fuel
injector operating
sound
• Faulty PGM-FI system
(P.9)
• Faulty fuel injector
8. Test cylinder
compression*
• Valve clearance too small
• Valve stuck open
• Worn cylinder and piston
ring*
• Damaged cylinder head
gasket
• Improper valve timing*
• Seized valve
9. Start by following
normal starting
procedure
• Insulator leaking
• Improper ignition timing
(Faulty ECM or CKP
sensor)*
• Fast idle knob stuck open
or damaged
• Fuel contaminated
ENGINE LACKS POWER
CHECK POSSIBLE CAUSES
1. Check the wheel
spin smoothness
• Brake dragging
• Worn or damaged wheel
bearings
• Bent axle shaft
• Drive chain too tight
2. Check the tire
pressure (P.119)
• Faulty valve core
• Punctured tire
3. Check the engine
speed change
accordingly when
clutch is engaged*
• Clutch slipping
• Improperly adjusted
clutch lever freeplay
(P.73)
• Worn clutch discs/plates
(P.76)
• Warped clutch discs/
plates (P.76)
• Weak clutch springs*
• Sticking clutch lifter
• Additive in engine oil
4. Check the engine
speed increase
• Dirty air cleaner element
• Clogged muffler
• Fast idle knob stuck open
or damaged
• Restricted fuel fill cap
breather tube
• Restricted fuel flow
CORRECT
INCORRECT
CORRECT
LOW
ENGINE
STARTS BUT
SOON STOPS
CORRECT
INCORRECT
CORRECT
INCORRECT
GOOD
NO GOOD
GOOD
NO GOOD
5. Check the engine
knocking when
accelerate or run
the engine at high
speed
• Worn piston and cylinder*
• Use of poor quality fuel
• Excessive carbon build-
up in combustion
chamber
• Ignition timing too
advance (Faulty ECM)*
• Lean fuel mixture
6. Check the ignition
timing*
• Faulty ECM*
• Faulty CKP sensor*
7. Test cylinder
compression*
• Valve clearance too small
• Valve stuck open
• Worn cylinder and piston
ring*
• Damaged cylinder head
gasket
• Improper valve timing*
• Faulty decompressor
system*
8. Check the PGM-FI
system (P.7)
• Faulty PGM-FI system
(P.9)
9. Check the fuel
pump operation
and inspect the fuel
flow*
• Faulty fuel pump unit*
• Clogged fuel pump filter
10.Check the spark
plug condition
(P.78)
• Incorrect spark plug
• Incorrect spark plug gap
• Dirty air cleaner element
11.Check the engine
oil level and
condition (P.63)
• Engine oil level too high
• Engine oil level too low
• Contaminated engine oil
12.Remove the
cylinder head cover
and inspect
lubrication
• Faulty oil pump*
• Faulty pressure relief
valve*
• Clogged oil passage*
• Clogged oil strainer
screen*
NO
YES
CORRECT
INCORRECT
CORRECT
LOW
CORRECT
INCORRECT
CORRECT
INCORRECT
CORRECT
INCORRECT
CORRECT
INCORRECT
INCORRECT