Honda CRF450X 2005 Service Manual page 119

TROUBLESHOOTING
Engine w ill not start
• Too much fuel getting to the engine
- Air cleaner clogged
- Flooded carburetor
• Intake ai r leak
• Fuel contaminated/deteriorated
• No fuel to carburetor
- Fuel filter clogged
- Fuel line clogged
- Fuel valve stuck
- Float level m isadjusted
- Fuel tank breather hose clogged
• Slow circuit clogged
• No spark at plug (faulty spark plug or ignition system malfunction) (page 4-12)
Lean mixture
• Fuel jets clogged
• Fuel tank breather hose clogged
• Fuel filter clogged
• Fuel hose restricted
• Float valve faulty
• Float level too low
• Air vent hose clogged
• Intake air leak
Misfiring during acceleration
• Ignition system faulty (page ' 8-5)
• lean mixture
Afterburn during acceleration
• Ignition system faulty (page 18-5)
• Lean mixture
• Accelerator pump faulty
Rich mixture
• Choke valve in the "ON " posit ion
• Float va lve faulty
• Float level t oo high
• Air jets clogged
• Air cleaner element contaminated
• Flooded carburetor
Engine stalls, hard to start, rough idling
• Fuel l ine restricted
• Ignition system malfun ction (page 18-5)
• Low cylinder compression
• Fuel mixture too lean/rich
• Fuel contaminated/deteriorated
• Intake air leak
• Float level misadjusted
• Fuel tank breather hose clogged
~
• Pilot screw misadiusted
• Slow circuit or starting enrichment circuit clogged
• Idle speed misadjusted
• Air cleane r clogged
Poor performance (driveability) and poor fuel economy
• Fuel system clogged
• Ignition system faulty (page 18-5)
• Ai r cleaner clogged
Afterfiring
• Ignition system malfunction (page 18-5)
• Carburetor malfunction
• Lean mixture
• Rich mixture
FUEL SYSTEM
6-5