Engine - Suzuki RM-Z450 Owner's Service Manual

3-2 TROUBLESHOOTING

ENGINE

Complaint
Engine will not start
or is hard to start.
Engine idles poorly. • Valve clearance out of adjustment
Engine stalls often.
Symptom and possible causes
Compression too low
• Valve clearance out of adjustment
• Worn valve guides or poor seating of valves
• Mistiming valves
• Excessively worn piston ring
• Worn-down cylinder bore
• Poor seating of spark plug
• Broken, cracked, or damaged piston
• Defective automatic decomp.
Plug not sparking
• Fouled spark plug
• Wet spark plug
• Incorrect spark plug gap
• Defective spark plug cap
• Defective ignition coil
• Defective CDI unit
• Open-circuited wiring connections
• Defective magneto
No fuel reaching the carburetor
• Clogged fuel tank vent hose
• Clogged or defective fuel valve
• Clogged fuel hose
• Defective carburetor float valve
• Valve timing out of adjustment
• Poor seating of valves
• Worn valve guide
• Worn down camshafts
• Incorrect spark plug gap
• Defective ignition coil
• Defective CDI unit
• Defective magneto
• Defective throttle position sensor
• Sucking air from intake pipe
• Insufficient throttle cable play
• Dirty spark plug
• Defective ignition system
• Clogged fuel hose
• Valve clearance out of adjustment
Remedy
Adjust
Repair or Replace
Adjust
Replace
Replace
Retighten
Replace
Clean or replace
Clean
Clean and dry
Adjust
Replace
Replace
Replace
Repair or replace
Replace
Clean or replace
Clean or replace
Clean or replace
Replace
Adjust
Adjust
Repair
Replace
Replace
Adjust
Replace
Replace
Replace
Adjust or replace
Retighten or replace
Adjust
Replace
Replace
Clean
Adjust