(1983) honda vf750 problems?

i have a 83 honda vf750 and when i take off it makes a puttering noise but once i get my rpms up it runs fine. as soon as i let off and start letting my rpms go down it makes that puttering noise again. sounds fine on idle. slowing down for a stop light for example it makes that sputtering noise. any ideas would be greatful. if you got questions let me know.