Motorcycle Repair: some engine noise after oil change., cylinder head gasket, piston slap

Question
Hi,

I have a 1986 Honda CMX 450 Rebel. I've had it for about 2 years with no problems. I lent my bike to my buddy last week and he returned it saying that the oil pressure light was turning on and off. I checked the oil level and it was low so I did an oil change and oil filter change. The last oil change was about 300 miles ago. The bike runs fine, but the engine sounds a little rough during the first 3 gears. It sounds a little like a rattle, but disappears once 6th gear is reached. The bike has 42,000 miles and had a tune up about 800 miles ago. I was wondering what your thought the problem might be.
Thanks for your help.

Answer
Hi Dave,

I would have to hear the sounds to accurately diagnose the source.

Review the following lists.

Respectfully,
Mark Shively



Abnormal Engine Noise:

Knocking:

IC igniter trouble
Carbon built up in combustion chamber
Fuel poor quality or incorrect
Spark plug incorrect
Overheating

Piston slap:

Cylinder/piston clearance excessive
Cylinder, piston worn
Connecting rod bent
Piston pin, piston holes worn

Valve noise:

Engine not sufficiently warmed up after lash adjuster installation
Hydraulic lash adjuster damaged (worn, seizure, or spring broken)
Air in hydraulic lash adjuster
Metal chips or dust dammed in hydraulic lash adjuster
Engine operated in red zone
Valve spring broken or weak
Camshaft bearing worn

Other noise:

Connecting rod small end clearance excessive
Connecting rod big end clearance excessive
Piston ring worn, broken or stuck
Piston seizure, damage
Cylinder head gasket leaking
Exhaust pipe leaking at cylinder head connection
Crankshaft run out excessive
Engine mounts loose
Crankshaft bearing worn
Primary gear worn or chipped
Camshaft chain tensioner trouble
Upper or lower tension spring trouble
Camshaft chain, sprocket, guide worn
Air suction valve damaged
Balancer gear worn or chipped
Balancer shaft position maladjusted
Balancer bearing worn
Balancer coupling rubber damper damaged
Oil pump chain, sprocket worn


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Abnormal Drive Train Noise:

Clutch noise:

Weak or damaged rubber damper
Clutch housing/friction plate clearance excessive
clutch housing gear worn

Transmission noise:

Bearings worn
Transmission gears worn or chipped
Metal chips jammed in gear teeth
Engine oil insufficient

Drive line noise:

Bevel gear bearings worn
Bevel gears worn or chipped
Bevel gears maladjusted
Rear wheel coupling damaged
Insufficient lubricant

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Abnormal Frame Noise:

Front fork noise:

Oil insufficient or too thin
Spring weak or broken
Rear shock absorber noise:
Shock absorber damaged

Disc brake noise:

Pad installed incorrectly
Pad surface glazed
Disc warped
Caliper trouble

Drum brake noise:

Brake linings overworn or worn unevenly
Drum worn unevenly or scored
Brake springs weak or broken
Foreign matter in hub
Brake not properly adjusted

Other noise:

Bracket, nut, bolt, etc. not properly mounted or tightened