Troubleshooting - Honda CRF450R Manual Del Propietario Y Guía De Competiciones

Troubleshooting

The items that are serviceable using this Manual
are followed by the page number reference in
parenthesis. The items that require use of an
official Honda Shop Manual are followed by an
asterisk (*).
ENGINE DOES NOT START OR IS HARD TO START
CHECK POSSIBLE CAUSES
1. Check the spark INCORRECT • Incorrect spark plug heat
plug condition range
(P.71) • Incorrect spark plug gap
• Dirty air cleaner element
CORRECT
WEAK OR
2. Try spark test* • Faulty spark plug (P.71)
NO SPARK
• Fouled spark plug (P.71)
GOOD SPARK
• 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*
• Faulty condenser*
INCORRECT
3. Check the PGM-FI • Faulty PGM-FI system
system (P.11) (P.13)
CORRECT
4. Check the fuel INCORRECT • Faulty fuel pump*
pump operation • Clogged fuel pump filter
and inspect the fuel (P.48)
flow*
CORRECT
5. Test cylinder LOW • Valve clearance too small
compression* • Valve stuck open
• Worn cylinder and piston
CORRECT
ring*
• Damaged cylinder head
gasket
• Improper valve timing*
• Seized valve
6. Start by following ENGINE • Insulator leaking
normal starting STARTS BUT • Improper ignition timing
procedure SOON STOPS (Faulty ECM or CKP
sensor)*
• Fast idle knob stuck open
or damaged
• Fuel contaminated
ENGINE LACKS POWER
CHECK POSSIBLE CAUSES
1. Check the wheel INCORRECT • Brake dragging
spins smoothly • Worn or damaged wheel
bearings
CORRECT
• Bent axle shaft
• Drive chain too tight
2. Check the tyre INCORRECT • Faulty valve core
pressure (P.100) • Punctured tyre
CORRECT
3. Check the engine NO GOOD • Clutch slipping
speed changes • Improperly adjusted
accordingly when clutch lever freeplay
the clutch is (P.66)
engaged* • Worn clutch discs/plates
(P.69)
GOOD
• Warped clutch discs/
plates (P.69)
• Weak clutch springs
(P.69)
• Sticking clutch lifter
• Additive in engine oil
4. Check the engine NO GOOD • Dirty air cleaner element
speed increase • Clogged muffler
• Fast idle knob stuck open
GOOD
or damaged
• Restricted fuel fill cap
breather tube
• Restricted fuel flow
5. Check for engine YES • Worn piston and cylinder*
knocking when • Use of poor quality fuel
accelerating or • Excessive carbon build-
running the engine up in combustion
at high speed chamber
• Ignition timing too
CORRECT
advanced (Faulty ECM)*
• Lean fuel mixture
INCORRECT
6. Check the ignition • Faulty ECM*
timing* • Faulty CKP sensor*
CORRECT

Troubleshooting

7. Test cylinder LOW • Valve clearance too small
compression* • Valve stuck open
• Worn cylinder and piston
CORRECT
ring*
• Damaged cylinder head
gasket
• Improper valve timing*
• Faulty decompressor
system*
8. Check the PGM-FI INCORRECT • Faulty PGM-FI system
system (P.11) (P.13)
CORRECT
9. Check the fuel INCORRECT • Faulty fuel pump unit*
pump operation • Clogged fuel pump filter
and inspect the fuel (P.48)
flow*
CORRECT
10.Check the spark INCORRECT • Incorrect spark plug
plug condition • Incorrect spark plug gap
(P.71) • Dirty air cleaner element
CORRECT
INCORRECT
11.Check the engine • Engine oil level too high
oil level and • Engine oil level too low
condition (P.54) • Contaminated engine oil
CORRECT
INCORRECT
12.Remove the • Faulty oil pump*
cylinder head cover • Faulty pressure relief
and inspect valve*
lubrication • Clogged oil passage*
• Clogged oil strainer
screen*
149
Tips