Motorcycle Repair: A novice looking for an expert opinion, fuel air mixture, friction zone

Question
Just bought a honda shadow v500cc 1985. She ran well the first few days..has 18,000k...i decided to change spark plugs because it was due...Later that day , about 15 miles later, the bikes friction zone was real bad, if i left off the clutch even a slight bit the engine would die. It would immediately start back up. After one start up i began riding and noticed the pickup was real slow, the rpm did not pass 3 or 4 and when in OD would not pass 45 and the bike can go about 70 easy before. I checked the plugs and one was really dark only after 15 miles . I chnaged both again just to see if it would make a difference. Still nothing, if you have any idea i would appreciate it, im a young man who needs the bike to get to work everyday...please help...

Answer
Hi Mel,

I suspect the choke was applied after the engine was up to operating temperatures. Just a hunch.

If not, the problem may be a faulty ignition system or varnished carburetors. The list is long of possibilities. A tech could check the problem very quickly.

If this is a recent purchase from a dealership, return it and complain a bit, respectfully.

You can see microfiche parts and buy parts & service/repair manuals at "www.bikebandit.com"


Respectfully,
Mark Shively



Poor Running at Low Speed: (all makes/models general)

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