While riding i had a loss of power when i pulled over i heard a metallic pinging sound. I localized it with a stethoscope to the exhaust area on the head, the sound can't be heard over 2000 rpm. I removed the valve cover and inspected lash. Intake 0.15 exhaust 0.20. (Stage 2 hotcams, Kibblewhite valves, MCCT, CW BB kit, new timing chain, all 2000 km ago) I removed the cams and inspected only to find no anomalies except a thin black film on the cams. Then engine has been running beautifully since broken in. I found some lateral play on the exhaust decompression valve http://vid409.photobucket.com/albums/pp174/rukik/20150810_150818_zpsnpfjta2d.mp4 . I don't know if this could be the sound or if it is an exhaust valve. Would a valve make noise and still allow an engine to run? or are they like a one shot deal, where if the go that is it?