The cylinders should heat up the same. I would try redoing the spark plug wire connections. if the wire appears to be oxidized, nip off the ends a tad. or get new plug wires. or it could be the coil. you could also try swapping the coils or spark plugs. I don't think the (+) & (-) stuff matters. It's mentioned in the 81 650 manual in regards to the primary wire connections, but it doesn't specify the spark plug wire connections.
