After listening to what I thought was certainly the timing gear typical racket I first substituted temporarily the fuel pump with an electrical but the clatter (noise) persisted I pulled the grill, rad, timing gear cover and both crank and cam gears. Nothing appears excessively loose between the gear(s) or on either drive or driven 'keys' There is a ridge however worn into the brass or copper cam retainer which seems odd - there were no spacer shims as I see a comment in the manual about clearance - and thoughts. The noise is at low speed and seems to subside then above 2000 rpm or when the oil is cold ... any thoughts, thks Greg