Thats what mine was. The mount up under the gas tank has a couple screws that were less than hand tight. I tightened those up and all is good.
Like others have said, the first step is to check all the mounts on the engine and exhaust. After that you may need to look at the retaining nuts on the crankshaft and counter balance, there have been a couple of instances where they were not tight enough and sheered the woodruff keys. It's not a big deal if you catch it early but don't let it go to the point that something spins on the shaft, that could be bad.
