i have an 85 700 when i got it one carb was missing a needle so i put a dino jet kit in it and new carb boots. it runs all right but it will pop out the exhaust on excell then at 3 to 3500 it will take off some times it will pop out the intake
Try adjusting your pilot screws. Check the condition of your plug and see if it is wet, dry or black and sooty. You are probably getting too much fuel to that cylinder.