Pull the plugs, put the plugs back into the caps, ground the plugs on the head/cylinder, turn the bike over a few times, look for oil to come out the plug holes.
When my son's Mustang spent some time on its roof, there was oil in the combustion chambers, and it locked trying to turn over. We pulled the plugs, sprayed carb cleaner into the holes and then turned it over a few times, watched the stuff come spraying out. Re-installed the plugs and it started up, smoked like gangbusters for awhile and eventually cleaned itself out.
Get fit. Stay safe. Enjoy life. Learn something to help someone in need.