I bought a 1978 gs 750 e about a month ago. Needed it's lights rewired but other than that it was in good shape. Rode it for a couple days than all of a sudden it bogged down. I can get the old girl ta start, but she is only firing off the first two cylinders. Cylinders 3 and 4 don't even get warm. They are getting fuel, [spark plugs are whet when I pulled them] and I switched the plugs around to make sure they are ok. All the plugs work. I'm certain it's getting compression, but don't actually have a meter to gauge properly. Have no clue what to look into next, and it's my main mode of transportation at the moment. Please, if any one could throw some ideas out there. I'd be very thankfully.