HOME Pre-Ignition or Detonation (Knocks or Pings) 1. Fuel octane rating too low. LUBRICATION SYSTEM 2. Faulty spark plugs. Engine Uses Too Much Oil Or Smokes Excessively 3. Incorrect spark plug for the kind of service. 1. Restricted breather operation. 4. Excessive carbon deposit on piston head or in combustion chamber. 2. Restricted oil filter. 5. Ignition timing advanced due to faulty sensors (MAP and/or CKP). 3. Piston rings badly worn or broken. 4. Valve guides or seals worn. 6. Air leak. 5. Oil diluted with gas. Engine Leaks Oil From Cases, Hoses, Etc. Overheating 1. Loose parts. 1. Insufficient oil supply or oil not circulating. 2. Insufficient air flow over engine. 2.
Imperfect seal at gaskets, washers, etc. 3. Heavy carbon deposit. 3. Restricted breather hose to air filter. 4. Ignition timing retarded due to faulty sensor(s): Manifold Absolute Pressure (MAP) and/or Crank Position (CKP). 4. Restricted oil filter. 5. Porosity. 5. Leaking valve. 6. Radiator dirty, plugged. Low Oil Pressure 7. Insufficient coolant supply. 1. Oil sump underfilled. 2. Faulty low oil pressure switch. 8. Vent hose crimped. 3. Oil pump O-ring damaged or missing. 9. Air in cooling system. 4. Bypass valve stuck in open position. Valve Train Noise 1. properly or oil passages obstructed. 2. Valve sticking in guide. 3. Chain tensioning spring or shoe worn. 2.
Bypass valve stuck in closed position. 4. Cam timing incorrect. ELECTRICAL SYSTEM 5. Secondary cam tensioner out of range. NOTE Excessive Vibration 1. Wheels and/or tires worn or damaged. For diagnostic information see the ELECTRICAL DIAGNOSTIC MANUAL. 2. Engine/transmission/rear wheel not aligned properly. Alternator Does Not Charge 3. Upper engine mounting bracket loose/broken or mounting bracket pre-loaded. 1. Voltage regulator module not grounded. 2. Engine ground wire loose or broken. 4. Ignition timing advanced due to faulty sensor inputs (MAP and/or CKP)/poorly tuned engine. 3. Faulty voltage regulator module. 5. Internal engine problem. 4. Loose or broken wires in charging circuit.
6. Broken frame. 5. Faulty stator and/or rotor. 7. Engine counterbalancer out of time or bearing failed. 8. Exhaust system binding or hitting frame. Alternator Charge Rate Is Below Normal 1. Weak or damaged battery. Check Engine Light Illuminates During Operation 2. Loose connections. 3. Faulty voltage regulator module. Fault detected. See the Electrical Diagnostic Manual. 4. Faulty stator and/or rotor. Speedometer Operates Erratically 1. Contaminated vehicle speed sensor (remove sensor and clean off metal particles). 2009 VRSC Service: Maintenance 1-71 ed pump not func ted. 5. Oil diluted with gas. tioning 6. Open in oiling circui High Oil Pressur 1. Oil sump overfilled.