I have a kerker 4-1 Exhaust on a stock bike, stock airbox, stock filter. Joe Raulf at Boxenstopp told me to go to 165 mains. Everyone else said either Mikuni 155 or 157.5. I asked Joe if he was talking about Dynojet or mikuni, he said mikuni 165. So I went home to look at my plugs. With shimmed...