I'm getting a vibration/bounce at 70 mph and above on my 650R. It's not a head shake....but more of a fast up and down bouncing feel to it. It get's kinda uncomfortable at that speed. The bike is already set up with a Scott's damper and SRC fork brace. The previous owner had an aggressive DOT knobby on the bike. I switched to a less aggressive front tire and still have the concern. He also sprung the bike for a 240lb. rider. I'm about 190lb. Will the heavier springs be my concern or should I look at balancing the tire? Thanks!