Odd motor noises

[HondaRacing83]

I know its an air cooled motor and all but lately theres been new odd noises. Theres tge normal 400ex valve tick but now when i start it up it makes these pinging noises. And when im riding and hit low rpms theres like a grunting or grinding it soundslike its in the bottom end somewhere

[OZ-T]

Have you changed the oil lately? I changed mine this weekend, 10w30 full synthetic instead of regular oil and it quieted my engine down a bunch, the valve rattle is barely noticeable now.

[on the rocks]

hope the 10w30 synthetic wasn't a car oil. it would be waaaay to slick for a wet clutch.