Just got by bike and the 66cc kit, put it all together last week, got running ok. Noticed exhaust was full of oily black stuff so I placed carb pin from 2 slot to 1 slot. reduced the fowling but caused the bike to run too lean and I blew a hole through the top of the cylindar about the size of the quarter... Lesson learned...DO NOT LEAN THE FUEL TOO MUCH! Any one else learn from the school of hard knocks?