STOCK JETTING IS 168 MAIN AND 52 PIOLOT. RUN A BOTTLE(3.5OZ) OF LUCAS 2-STROKE OIL TO 1 GALLON OF GAS AND SEE HOW FAST U STOP FOULING. ITS A SMALL 3OZ. BOTTLE AT AUTOZONE. THIS IS A 50:1 RATIO (LEAN)BUT THESE HONDA 2CYCLES RUN BETTER LEAN. IM AN MMI TECH AND USE TO RECCOMEND 32:1 BUT IT JUST DOESNT FLY WITH THESE CR´S. I LIVE IN RENO NV. AT 4,500´ ELE. I RUN A 160 MAIN AND 42 PIOLOT WITH A DG PIPE AND SILENCER AND THIS BIKE ROCKS IT UP WITH 250´S BUT IT CANT TOUCH MY YZF450. REMEMBER: IF U MAKE AN ENGINE EXHALE BETTER-U MUST MAKE IT INHALE EQUALLY AS WELL(A.FILTER) IF U GIVE AN ENGINE MORE AIR-U MUST GIVE IT MORE FUEL. AFTERMKT. PIPE KITS USUALLY COME WITH LARGER(FATTER/RICHER)JETS BC WHEN U GIVE AN ENGINE MORE AIR VOLUME U MUST GIVE IT MORE FUEL VOLUME. 50:1-40:1 THE LUCAS IS FULL SYNTHETIC AND U SHOULD ONLY USE A SYNTHETIC 2-STROKE OIL WHILE RUNNING 50:1. PEACE AND TREAD SOFT.