Hey there guys. My first post. Any ideas on an intermittent knocking coming from the left side of the crankcase (while sitting on the bike ) at idle, and on cold startup? The sound almost dissapears when hot. I can't feel it when I put my hand on the case (on start up). Only things done to the bike are the improved clutch plates and springs from Hitchcocks and a Carbury vibration reduction plate, 3000 KMS ago.