I have a 1982 Spectra 750-N. I just bought the bike and I got it running right briefly. However, now sometimes it runs off 2 cylinders and then other times runs off of 4. It idles great and when I give it gas it acts as if it dosent want to run. It stutters and backfires. I looked over the wiring and found some pretty bad looking wire. Should I start with a wiring harness or something else? Any suggestions? I know the carbs are good. I just cant figure out why it is doing this. I just dont know much about the electrical side of things. Can someone please help?!?!?