A bad wrist pin can give you a thud and hard knock, a slapping piston usually is like hydraulic lifter noise, only does it hot istead of cold!
And the verdict is (drumroll please…) bad wrist pin. I took it to another official Honda mechanic, and the tell-tale was getting worse at hot, not much noise at cold, and doesn’t change intensity with throttle load. The alum pistons grow faster than the pin at hot engine temp, ergo more slop. Looks like I am in for a motor unless there is a cheaper fix for wrist pins.
Are you saying the problem is with the bushing in the small end of the con. rod or with the wrist pin itself or with the hole in the piston that the wrist pin goes through?
I think only a teardown and inspection will pinpoint this
As it turns out the first Mechanics advice was spot-on,just drive it.