I just picked up a 1978 cx500. It ran ...ok for a few days now im starting to notice that it lacks power. if i dont ease on the throttle ever so gently it bogs itself out. when i do finally get it up to speed i hold the throttle steady but the bike jerks like im letting go of the throttle. If i try to pin it at any speed it bogs down and has no power. The bike basically will not acelerate properly. I need help.im a car guy this is my first bike.