Engine noise after top end rebuild

I just installed a new 300cc S3 "A" cylinder and "A" piston.
Assembly went smoothly.
When I run the bike, it starts up easy as it should and runs fine. However, I am hearing a low frequency knock or chatter. Not a ping sound but a low sound.
This was not present a few hours prior with the old cylinder. So I can safely rule out low end or rod bearings or exhaust o rings right?

My question is. Is this normal for this to make this noise? Does it have anything to do with using 2 stroke oil to lube parts on assembly? How about cleaning my PV assembly? Maybe it is not yet lubed enough?

Here is a link to a video of the sound.

Anyone have any experience with this?

https://vimeo.com/60549378