Was wandering if anyone had any ideas of anything to check before I pulled it down & looked at the piston. I have rebuild a couple 4 wheeler engines but never had a dirt bike. Guess a 4 cycle is a 4 cycle. Just bought it as is & know nothing about the up keep of the bike! Any suggestions is appreciated.

06 kawasaki klx300r
06 kawasaki bayou 300 4x4
11 suzuki king quad 500 4x4