When my 08 Vee suddenly started sputtering and coughing, I was 500 miles from home. I had to feather the clutch quite a bit in order to get the rpms up high enough that the bike would want to run at what felt like normal. Any pull up an incline demanded down shifting and running the rpms up in order to maintain speed. It started backfiring inside the air box. Is your sputtering and coughing leading to any of these symptoms? For my Vee, it turned out to be a clogged high pressure fuel filter on the fuel pump inside the tank. I would suggest you do the fuel flow test to ensure you are getting adequate fuel when your wrist demands it. There are a bunch of threads on the forum for how to do that. If the flow is inadequate, read up on doing the external fuel filter bypass. IF the fuel flow is sufficient, then check the boots inside the air box connecting to the throttle bodies. Make sure they are sealed properly and not allowing air to bypass. Also, check up on performing a throttle body sync so that both are pulling at the same pressures. All of these are easy to do and all of them are covered in numerous threads here.Recently bought a used 04 Vee ...now the bike is sputtering and coughing at mid-range ( between 3 and 4 thousand rpm).