Engine rattling

[airb]

I have a raptor 350 and it makes a rattling noise when it get into the mid rpm range. It started occurring after riding home one night following a sudden loss of power. I babied it home and took the valve covers off and everything seems okay. I don't have a gaping tool so I cant be sure on the clearances but they don't appear crazy loose or anything. I change the oil at least every 10 hours but I do ride the bike hard as well. I rode it from my back yard to my front and it runs great, just makes a rattle after and during mid rpm. Hoping its vavletrain related and not the bottom end or something.
Appreciate all the help.

 

[YAMAHAULER]

make sure all the motor mount bolts are tight first
otherwise it could be crank bearings or connecting rod bearing going
could also be the cam bearing going too

 

[Gen1Pat]

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