I'm just wondering if all of your 06rstd's/ventures have a whirring sound like a jet engine when you roll the throttle? I was out Saturday and parked beside a venture that didn't have that sound. Mine has, since it was bought new last August. I thought it was due to the 4 cylinders? Milage and acceleration are both great but definitely doesn't have a V-twin sound. Should I be worried? What can you yama-experts tell me?