We recommend performing a cylinder soak to clean the piston crowns and compression rings and landings. To do this, remove the spark plugs and pour Berryman B-12 Chemtool Carburetor, Choke & Throttle Body Cleaner (part #0116) into each cold cylinder in quantities sufficient to cover the entire pistons and then thread the spark plugs back in finger-tight. A typical soak time is a couple hours, but if leak-down is minimal, you can soak overnight, too. (A little 0116 in the oil is not problematic as the solvents will boil off the first time the engine reaches operating temperature.) For best results, rock the motorcycle occasionally to gently agitate the cleaner. Remove the spark plugs, suction out the combustion chamber, and reinstall the plugs and plug wires. Once you’re done with the cylinder soak, we recommend using an in-tank fuel additive for PM. In order to keep the fuel injectors (or carb), intake valves, and combustion chambers clean, try Berryman [7516]. Treat rate is 1 fl oz/gal, so you can generally expect to get 3 or 4 treatments from a single can.