Motorcycle Repair: 1987 FXRS runs on one cylinder, piston rings, fxrs


Question
I have had a recurring problem with my bike running on one
cylinder.  I had originally thought it was fuel related, so i
replaced the fuel line, added an in-line filter, rebuilt the carb,
and cleaned out the gas tank of any debris and used muriatic
acid to clean out the Kreem liner. The fuel system is not the
problem! The strange part of the bike's problem is that it will
run fine for 40-50 miles and then start running on one cylinder
and then die. Or the problem starts right away before i take off. I
checked the spark plugs and theres a light oil on them. I
attribute this to a weak battery or bad piston rings.  I'm going to
put a new battery in this afternoon and hopefully it clears up my
problems but if not where else should i turn my attention to?  
Any help would be greatly appreciated sir.

Thank You

David Karow Jr.

Ride Free

Answer
When the bike starts running on one cylinder, change the plug wires from one to the other. If it was the front cylinder not running, is it the back one now?
If that is the case then either you plug wires are bad or the coil is bad. If this is not the problem let me know
Light oil on hte plugs means either your rings are wore or the valve guides are wore
Good luck and happy riding
Mike