Hello every1...in my never ending initial learning phase on my 70T, I have become more comfortable pushing it slightly......when revving over 5k in second and third I notice a mild vibration that seems to be coming from the engine(I feel it most in my seat back)...I realize this could be a little vague to properly diagnose but what should I consider before having a pro check it out....it seems to improve at around 5400k.......stock engine/exhaust w/115k and worn valve guides........