That is a canny solid clunk, whip off the valve cover and have a look at what's going on in there, sound like the piston is hitting a valve :-/
Give the rockers a wiggle by hand see if any feel loose, check none of the pushrods have dislodged, wind the engine back the opposite way and see where in the rotation it hits again, after that pull off the rocker gear one pair at a time and rotate between removals to identify which cylinder it is, if it's a valve, does seem like either something in the engine, though I'm pretty sure the valves don't open far enough to hit a the piston
oh sorry my comp cant see your vids , ill let someone who can .Hope you get it sorted . Stops dead ??
If it is a valve getting slapped by the piston, when you turn the engine as you did by ha d in the vid, can you feel it at the rockers for no.1? Just spitballing here but would have thought it would feel the clunk up through the rocker?
Click photo to view video. I turned the crank a bit up to the stopping point so you can see the tappets in motion before the stoppage
Hard to tell, is that pics of both heads/ rockers? Stops dead I would guess is something in a cylinder. A bit of carb, a nut, washer, tinware screw?
They look OK to you? No valves stuck? Pushrods in position? More straw clutching - something has got inside a barrel. Plugs out, magnet on a stick? Pretty sure the pistons can't hit the valves.
Ok I'm off to get a magnet on a stick. Thing is, it was running and still turning over albeit with a tapping, so I'm not sure what could have got in there. Or why it is stuck now.
