mine had a really bad clatter that made me think the rockers were starved of oil and they were because I had put the pipes on the wrong way
, this was also added to with piston slap but this is a story that I covered some time ago. my next clattering came last summer on a hot day and I convinced myself the rockers were being starved so I checked and this wasn't the case
, the bike has a rubber mounted honda tank and has carpet underlay wrapped around the frame. as I sat uprightish [ clip-ons fitted] it was terrible but as I leaned out to listen to the rockers it was ok.
so I took the tank off and replaced the old mounting rubbers and underlay, this cured my rattle . I am not saying this is your problem but tank mounting is a thought