Starter Motor Does Not Operate or Does Not Turn Engine Over
1. Engine stop switch in OFF position.
2. Ignition key switch not ON.
3. Discharged battery or loose or corroded connections. (Solenoid chatters.)
4. Starter control relay or solenoid not functioning.
5. Electric starter shaft pinion gear not engaging or overrunning clutch slipping.
6. Clutch lever not pulled in. Vehicle in gear.
7. Starter interlock circuit malfunction
Engine Turns Over But Does Not Star
1. Fuel tank empty.
2. Discharged battery, loose or broken battery terminal connections.
3. Fouled spark plugs.
4. Loose or shorting spark plug cables or connections.
5. Ignition timing badly out of adjustment.
6. Loose wire connection at coil or battery connection or
plug between ignition sensor and module. See Section 4.
7. Ignition coil not functioning.
8. Ignition module not functioning.
9. Ignition sensor not functioning.
10. Sticking or damaged valve or valves.
11. Engine oil too heavy (winter operation).
12. Ignition circuit interlock malfunction.
13. No output from the ECM. See dealer.
14. Inadequate fuel pressure in fuel lines (possible leak).
15. Clogged fuel filter. See dealer.
16. Clogged fuel injectors. See dealer.
17. Tripped bank angle sensor. Turn key to OFF, wait 15 seconds, and then back to IGN again to start bike.
18. TP Sensor/fast idle screw not set properly. See dealer.
19. No output from CMP sensor. See dealer.
20. Inoperative fuel pump. See dealer
1. Spark plugs in bad condition, have improper gap or are partially fouled.
2. Wires are crossed.
3. ATC in stuck open.
4. Spark plug cables in bad condition and shorting.
5. Battery nearly discharged.
6. Loose wire connection at one of the battery terminals, at coil or at plug between ignition sensor and module.
7. Throttle controls not adjusted correctly.
8. Ignition coil not functioning.
9. Engine oil too heavy (winter operation).
10. Ignition not timed properly. See dealer.
11. Vapor vent valve plugged or fuel line closed off restricting fuel flow.
12. Water or dirt in fuel system.
13. Air leak at intake manifold.
14. Valves sticking.
15. TP Sensor and/or fast idle screw not set properly. See dealer.
16. Oxygen, IAT or ET sensors damaged or malfunctioning.
Starts But Runs Irregularly or Misses
1. Spark plugs in bad condition or partially fouled.
2. Spark plug cables in bad condition and shorting.
3. Spark plug gap too close or too wide.
4. Ignition coil not functioning.
5. Ignition module not functioning.
6. Ignition sensor not functioning.
7. Battery nearly discharged.
8. Damaged wire or loose connection at battery terminals or coil.
9. Intermittent short circuit due to damaged wire insulation.
10. Water or dirt in fuel system and throttle body or filter.
11. Vapor vent valve plugged.
12. Throttle controls improperly adjusted.
13. Air leak at intake manifold or air filter.
14. Damaged intake or exhaust valve.
15. Weak or broken valve springs.
16. Incorrect valve timing.
17. Oxygen, IAT or ET sensors damaged or malfunctioning.
18. TP Sensor not set properly. See dealer.
19. Fuel level too low. Add gasoline.
20. Inoperative fuel injector. See dealer.
21. Obstructed fuel tank vent valve or pinched vent tube. See dealer.
Spark Plug Fouls Repeatedly
1. Incorrect spark plug.
2. Piston rings badly worn or broken.
3. Valve stem seals worn or damaged.
4. Valve guides badly worn.
5. Sensors damaged.
6. Air intake screen covered or restricted.
Pre-Ignition or Detonation (Knocks or Pings)
1. Excessive carbon deposit on piston head or combustion
2. Incorrect heat range spark plug.
3. Spark plugs not firing.
4. Ignition timing advanced.
5. Fuel octane rating too low.
6. Intake manifold vacuum leak.
1. Insufficient oil supply or oil not circulating.
2. Clogged or damaged fins on oil cooler.
3. Cooling fan not operating properly.
4. Leaking valves.
5. Heavy carbon deposit.
6. Ignition timing retarded.
Valve Train Noise
1. Hydraulic lifter not functioning properly.
2. Bent push rod.
3. Cam, cam gears or cam bushings worn.
4. Rocker arm binding on shaft.
5. Valve sticking in guide.
1. Engine tie-bars loose, broken or improperly spaced.
2. Isolator mounting fasteners loose.
3. Broken frame.
4. Primary chain badly worn or links tight as a result of insufficient lubrication.
5. Wheels not aligned and/or tires worn.
6. Internal engine problem.
7. Wheels not balanced correctly
Oil Does Not Return To Oil Tank
1. Oil tank empty.
2. Return pump gears damaged.
3. Oil feed pump not functioning.
4. Restricted oil lines or fittings.
Engine Uses Too Much Oil or Smokes Excessively
1. Piston rings badly worn or broken.
2. Valve stem seals worn or damaged.
3. Valve guides worn.
Engine Leaks Oil From Cases, Push Rods, Hoses
1. Loose parts.
2. Imperfect seal at gaskets, push rod cover, washers, etc.
To aid locating leaks, use BLACK LIGHT LEAK DETECTOR (Part No. HD-35457).
3. Restricted oil return line to tank.
4. Restricted breather passage(s) to air cleaner.
Alternator Does Not Charge
1. Regulator-rectifier module not functioning.
2. Stator not functioning.
3. Rotor not functioning.
4. Weak battery.
5. Loose connections.
Poor Fuel Economy
1. Oxygen sensor damaged or malfunctioning (bike running rich). See dealer.
2. Air intake screen covered or restricted.
For more information, please download the relevant fault bell repiar service manual pdf