i rebuilt this norton commando, knowing very little about motorcycles, but learning along the way, and repalcing most of the parts that looked worn, or were missing. i timed it statically. the valve clearances are correct. the noise sounds like it's coming from the engine head, but it's hard to tell. if anyone has heard this noise before and knows what it is, please let me know. i don't have any experience with these bikes, so i don't know really know where to start (piston slap? improper timing? something wrong with bad rockers/valves? pinging? no clue). i'm dying to ride this thing, but i don't even want it running at idle with that damn noise.