2004 Honda Recon 250 excessive valve chatter

[DexKing]

I recently got my hands on a free 2004 Recon that the owner had zero information on the machine or the history. Long story short, a little troubleshooting and research revealed i needed to replace the timing chain for it to stay running. when i opened the case, it the chain was so horribly stretched, that the tensioner pivot arm had play between it and the chain! I also found the oil pump chain totally disconnected from the sprocket due to being completely worn out. I tore the whole engine down and rebuilt it from the bottom up finding little things here and there that needed to be replaced. Upon inspecting the top end, i didn't find any bad/excessive play in the crank, rod bearings or wrist pin. Now the machine runs great, but even after 2x adjusting the valves, the chatter is way more than you'd expect from a honda normally. My neighbor is an auto mechanic by trade, and i asked him to take a listen. the look on his face when i started it and it was chattering like that was priceless! He mentioned that maybe the valves themselves might be wore out or stretched. my question here: what all can cause the excessive rattle up in the valve cover aside from valves being out of spec? Everything else seemed to be in decent condition as far as rockers and guides go. I am fairly new to small engine/ATV repairs, but am learning as a hobby and have a fair amount of knowledge with how to do some wrenching. Thanks!

[Sha35297]

Are you certain that it is valve chatter and not piston slap?