Honda CRF450R 2009 Service Manual page 548

TROUBLESHOOTING
ENGINE DOES NOT START OR IS HARD TO START
19·2
1. Spark Plug Inspection
Remove and inspect spark plug .
Is the spark plug
in
good co ndition ?
YES - Incorrect spark plug heat range
Incorrect spark plug gap
Dirty air cleaner
Fast idle knob stuck open or damaged
NO - GO TO STEP 2.
2. Spark Test
Perform spark lest.
Is th ere good spark ?
ND loose or disconnected ignition syslem wires
Broken or shorted spark plug wire
Broken or shorted ignition
coil
Faulty CKP sensor(s)
Faulty alternalor coil
Faulty engine stop switch
Faulty ECM
YES - GO TO STEP 3.
3. Fuel Pump Inspection
Check for operation of the fuel pump and inspect the fuel fl ow.
Is
the fuel pump unit normal?
YES - GO TO STEP 4.
NO - Faulty fuel pump unit
4. PGM·FI System Inspection
Check the PGM·FI system.
Is the PGM·FI system no rmal?
YES - GO TO STEP 5.
NO - Faulty PGM·Ft system
5. Engine Starting Condition
Start engine by normal procedure.
Does the engine start then stops ?
YES - Improper fast idle knob operation
leaking insulator
Improper ignition timing (Faulty ECM or CKP sensor(s»
Contaminated fuel
NO - GO TO STEP 6.
6. Cylinder Compression
Test cylinder compression.
Is the c
ompression low?
YES - Valve dearance 100 small
Valve sluck open
Worn cylinder and piston rings
Damaged cylinder head gasket
Seized valve
Improper valve timing