81 Yamaha Maxim XJ650

[Thomas Miller]

Hi All,
i have a 81 Yamaha Maxim XJ650 that ran fine until i took the Carbs apart and replaced all the Screws, inlets and seal. i installed it back into the bike and it doesn't seem to be running right anymore. it seems like it stutters when in idle and then taking off from a stop it almost chugs and doesn't seem to change? i know that one of the Spark plugs is not firing but i know it is most likely the ignition coil. does this sound right? what else could it be?
am new to the here, I have worked with multiple firms.
you can check facility management tool video one of my work.


Thanks,