Weird noise from top end?

[Moooools]

Hi
I was attempting to get my bucket started today, and after changing the spark plugs, the top end started making this weird clicking noise.
I took the head cover off and their seems to be something wrong with the valves on the right hand cylinder. It clicks just as the valves start to close.
Here is a video of it:



Any thoughts on what this could be?

[bucketracer]

If its bent valves? bent valves create excessive tappet clearance and instead of the cam quietly closing the exhaust and then opening the inlet, the cam gets flicked from the Ex lobe to The In lobe. Check for excessive tappet clearance.

Or it could be an overlong reach plug or one with an extended tip hanging up one of the valves which is then freed as the other valve opens and pushes it off the plug tip. Check for excessive tappet clearance appearing as you turn the motor over.

Loose timing chain tensioner allowing the cam to flick between lobes at TDC.

Wiggling the tappets as you turn the motor over may tell you something.

[Moooools]

Yeah I have checked the tappet already and it seems to be fine. There are no plugs in it in the video. Any other ideas?

[Moooools]

Keep in mind the engine has probably not been used for 10 years. And there is little or no oil present in the top end. Although it doesn't really seem like an oil issue to me.

[Moooools]

Found the noise! It was the top end cam sprocket. The retainer bolts was loose and as the cam moved over the valve-open positions the torque on the sprocket, due to from the valve springs, reversed due to and knocked against the retaining bolts.