Buell XB 2008 Series, Service Manual

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3. Piston rings badly worn or broken.
4. Valve guides or seals badly worn or damaged.
Pre-Ignition or Detonation (Knocks or Pings)
1. Fuel octane rating too low.
2. Faulty spark plugs.
3. Incorrect spark plug for the kind of service.
4. Excessive carbon deposit on piston head or in combustion
chamber.
5. Ignition timing advanced due to faulty sensor inputs.
6. Incorrect heat range spark plug.
7. Intake manifold vacuum leak.
Overheating
1. Insufficient oil supply or oil not circulating.
2. Insufficient air flow over engine.
3. Heavy carbon deposits.
4. Ignition timing retarded due to faulty sensor(s).
5. Leaking valve.
Valve Train Noise
1. Low oil pressure caused by oil feed pump not functioning
properly or oil passages obstructed.
2. Faulty hydraulic lifters.
3. Bent push rod.
4. Incorrect push rod length.
5. Rocker arm binding on shaft.
6. Valve sticking in guide.
7. Cam timing incorrect.
8. Cam, cam gears, or cam bushings worn.
Excessive Vibration
1. Wheels not aligned, rims bent, or tires worn or damaged.
2. Engine/transmission/rear wheel not aligned properly.
3. Primary chain badly worn or links tight as a result of
insufficient lubrication or misalignment.
4. Upper engine mounting bracket loose.
5. Ignition timing advanced due to faulty sensor inputs/poorly
tuned engine.
6. Internal engine problem.
7. Broken frame.
8. Stabilizer links worn or loose, or stabilizer link brackets
loose or broken.
Check Engine Light Illuminates During
Operation
1. Fault detected. See the Electrical Diagnostic Manual for
this motorcycle.
LUBRICATION SYSTEM
TOOL NAME PART NUMBER
BLACK LIGHT LEAK DETECTOR HD-35457
Oil Does Not Return To Oil Tank
1. Oil tank empty.
2. Oil pump not functioning.
3. Restricted oil lines or fittings.
4. Restricted oil filter.
5. Oil pump misaligned or in poor condition.
Engine Uses Too Much Oil Or Smokes
Excessively
1. Oil tank overfilled.
2. Restricted oil return line to tank.
3. Restricted breather operation.
4. Restricted oil filter.
5. Piston rings badly worn or broken.
6. Valve guides or seals worn.
7. Plugged crankcase scavenge port.
8. Oil diluted with gas.
Engine Leaks Oil From Cases, Push Rods,
Hoses, Etc.
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 breather hose to air cleaner.
4. Restricted oil filter.
5. Oil tank overfilled.
6. Lower rocker housing gasket installed incorrectly (upside
down).
7. Restricted oil return line to tank.
8. Porosity.
Low Oil Pressure
1. Oil tank underfilled.
2. Faulty low oil pressure switch.
3. Bypass valve stuck in open position.
4. Worn oil pump gerotor(s).
5. Restricted feed hose from oil tank.
6. Restricted high-pressure feed hose to oil filter housing.
7. Oil diluted with gas.
8. Open in oiling circuit.
High Oil Pressure
1. Oil tank overfilled.
1-48 2008 XB Service: Maintenance