Engine Rattle Noise

[JAinWO]

I have a CSC TT250 w 200 miles on it. Since I got it, there’s been an annoying background rattle-type noise when then engine is under load (higher RPM going uphill). It seems to be independent of engine RPM in that it doesn’t really increase in speed as the RPM increases once it starts making noise. Even so, I adjusted the valves and that didn’t help. I made a recording of it and sent it to CSC, but they couldn’t hear what I was referring to. Is this a normal noise w these bikes? I’ve never had a bike that did this and I had bikes from the 70/80’s. I attached the recording in a zip. CSC said maybe they play in the front sprocket as a guess. Any thoughts are appreciated!