Motorcycle Repair: Engine Noise, cylinder head gasket, piston slap

Question
K1 1200 Bandit, just under 7000 miles.
poor throttle response and knocking noise from just over tickover to 3000 rpm.
Had previously been advised could be a plug going out which could cause the poor throttle response and the knocking noise from the particular cylinder.  Have changed all plugs and air filter, but problem still there.
Would appreciate any advice you could give on this.
Thanks

Answer
Hi BJA59,

A tech needs to hear and see the machine to determine the source of the sounds. Need to perform a process of elimination of checks to offer an accurate diagnosis.

Use the below listed charts to try and diagnose the problem yourself.

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

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


Poor Running at Low Speed:

Spark weak:
Battery voltage low
Spark plug dirty, broken, or maladjusted
Spark plug cap or high tension wiring trouble
Spark plug cap shorted or not in good contact
Spark plug incorrect
igniter trouble
Pickup coil trouble
Ignition coil trouble


Fuel/air mixture incorrect:

Pilot screw maladjusted
Pilot jet, or air passage clogged
Air bleed pipe, bleed holes clogged
Pilot passage clogged
Air cleaner clogged, poorly sealed or missing
Starter plunger stuck open
Fuel level in carburetor float chamber too high or too low
Fuel tank air vent obstructed
Carburetor holder loose
Surge tank duct loose


Compression low:

Spark plug loose
Cylinder head not sufficiently tightened down
Cylinder, piston worn
Piston ring bad (worn, weak, broken, or sticking)
Piston ring/land clearance excessive
Cylinder head gasket damaged
Cylinder head warped
Engine not sufficiently warmed up after lash adjuster installation
Valve spring broken or weak
Valve not seating properly (valve bent, worn, or carbon accumulation on the seating surface)
Hydraulic lash adjuster damaged (worn, seizure, or spring broken)
Hydraulic lash adjuster oil passage clogged


Backfiring when decelerating:

Vacuum switch valve broken
Air suction valve trouble
Coasting enricher trouble


Other:

Igniter trouble
Carburetors not synchronizing
Carburetor vacuum piston doesn't slide smoothly
Engine oil viscosity too high
Drive train trouble
Final gear case oil viscosity too high
Brake dragging
Air suction valve trouble
Vacuum switch valve trouble

~~~~~~~~~~~~~~~~~~~~



Poor Running or No Power at High Speed:

Firing incorrect:

Spark plug dirty, broken, or maladjusted
Spark plug cap shorted or not in good contact
Spark plug incorrect
IC ignitor trouble
Pickup coil trouble
Ignition coil trouble


Fuel/air mixture incorrect:

Starter plunger stuck open
Main jet clogged or wrong size
Jet needle or needle jet worn
Air jet clogged
Fuel level in carburetor float chamber too high or too low
Bleed holes of air bleed pipe or needle jet clogged
Air cleaner clogged, poorly sealed, or missing
Surge tank duct poorly sealed
Water or foreign matter in fuel
Carburetor holder loose
Fuel tank air vent obstructed
Fuel tap clogged
Fuel line clogged


Compression low:

Spark plug loose
Cylinder head not sufficiently tightened down
Cylinder, piston worn
Piston ring bad (worn, weak, broken, or sticking)
Piston ring/land clearance excessive
Cylinder head gasket damaged
Cylinder head warped
Engine not sufficiently warmed up after lash adjuster installation
Valve spring broken or weak
Valve not seating properly (valve bent, worn, or carbon accumulation on the seating surface)
Hydraulic lash adjuster damaged (worn, seizure, or spring broken)
Hydraulic lash adjuster oil passage clogged


Knocking:

Carbon built up in combustion chamber
Fuel poor quality or incorrect
Spark plug incorrect
Coasting enricher trouble


Miscellaneous:

Throttle valve won't fully open
Carburetor vacuum piston doesn't slide smoothly
Brake Dragging
Clutch slipping
Overheating
Engine oil level too high
Engine oil viscosity too high
Drive train trouble
Final gear case oil viscosity too high
Air suction valve trouble
Vacuum switch valve trouble
Balancer mechanism malfunctioning