Motorcycle Repair: Suzuki1400 intruder, suzuki 1400 intruder, spark plug wires

Question
Hi
I own a 1991 suzuki 1400 intruder and i am having problems getting the front cylinder to to run properly.The bike has been to  a number of machanics here in cyprus.I have had the tank cleaned and sealed.carbs cleaned and jetted for straight through exhausts. I have put new fuel lines on and the carbs went back to the machanic to be ballanced.When i picked the bike up it sounded and rode great but when i got it home and went to go for a run later that day the front cylinder strted playing up again and not fireing all the time and back fireing.I checked the fuel was pumping to the carb and it was OK so i checked the plug it was a light deposit on the front plug.Please help

Answer
Keith,it may not be a fuel problem any more.Put in new spark plugs,on the plugs stay with NGK type but go to one number lower it hotter. Example the bike has BR8ES go to a BR7ES.Also on the end of the spark plug wires are resistors that have a 5ohm resistance.These do break down from time to time and are about $7.00 The may be breaking down and shorting out causing them to misfire.