So I am having troubles diagnosing why only my I'm running one cylinder.
I have power, the bike turns over and starts and the battery holds a charge. The fuel pump is working and all the lines are clear. Carburators seem to be working. Air filters are clean and I put new plugs. Also wires are fine, plugs both have spark. Can't figure out why I'm only running on the back cylinder though... help?

 

I have a question. How do you know it’s only running on one cylinder. I ask because being that it’s only a two cylinder engine if one’s not working I seriously doubt that it would run. Have you done a compression test? If you’re sure about the spark all you need is fuel and compression to make it run. I’d do the compression test first.