Hey guys, I run a Honda CR250 2001 - great machine! I just found out that my air screw was ½ turn too little outwards - making the mixture to rich. I noticed it because the bike started to leak oil out the exhaust connection points. I also checked the plug and the piston. Plug is black/oily. Piston is darkened too. (See photo) Now I readjusted it the air screw. Is there any procedure to undergo, like cleaning the piston/cylinder/plug before I run it? Thanks guys.