This is an '87 with 40k on the clock. I plan on doing a full write up - but, basically a bent rim condemned the bike to being eaten alive for five years straight by improper fuel management for storage. Someone bought the bike for $800 and replaced the pump and battery - hoping they were going to flip it. Two cylinders fired, keeping the bike running above 2k rpm, dying out if you tried to let it idle. It took 6500rpm in 6th to maintain 55mph. If you encountered an incline in the road - you were slowing to 40 mph - flat out. I bought the motorcycle after I heard it fire, never moving it or even sitting on it. A $50 rear rim, $200 for a carb cleaning, and a little elbow grease... It's been "in service" for me in Brooklyn for two days. Having two cylinders between your thighs in city traffic is not ideal, but regardless - this thing is a work horse through and through. I literally moved to new york city on it from six hours away... Work. Horse.
You need to get all four firing, driving for extended amounts of time on two cylinders can't be good for the engine. Odds are you have gas undetonated running down the cylinders mixing with the engine oil. You gotta fix this condition stat.
Undetonated? Why would I want my gas to detonate?! I like an even flame kernel, thank you. Haha, the carb cleaning got the rear two cylinders firing. It runs like a top... when the starter works.