Ok guys here is the deal never had this happen before i just put together a athena 421 motor with is my second one i have built with my first one still runs great what i have is when i take it out for a ride it runs great if you just run it but when you go from a dead stop and drop the hammer on it it dies like it floaded really bad or something if you take off normal then floor it it runs great the bike has t6 pipes 35mm pwks with 155 mains 48 poilts 1 1/2 turns on air screw +4 timing