Pro Circuit Sound Testing with John Mitcheff

Pro Circuit is serious about testing, with everything from suspension, to the motor, and of course, exhaust systems. The guys at PC still needed to do their sound testing for the stock 2013 Yamahas, so we lent them our YZ250F and YZ450F before they threw on their new T-5 exhaust. Ace mechanic, John Mitcheff, took us through the process.