looks like the engine got hot from the heat marks, maybe lack of oil, but I see oil running off the connecting rod in the picture. I dont know without putting my hands on it.
Have you ever tried Nicoderm?ok, jus took apart my 450 that had a severe smoking problem.
The old rings looked good.were the old rings scorched?
make sure you gap the new rings to the cylinder
Im sure honda specs are close.
I dont know on these motors if the pin is floating, bearing or pressed.
If it is pressed then you may want to change the rod if it got hot
if it got really hot there would be signs of bluing on the parts