Mark1 Motorcycle ExhaustDME Racings Mark1 Exhaust is a high performance tuned exhaust header featuring our unique reversion cone that creates back pressure naturally to deliver performance gains on the racetrack where you need it. Made to order, allow 2 weeks of build time. DME Racings Mark1 Exhaust is a high performance tuned exhaust header featuring our unique reversion cone that naturally creates back pressure to deliver performance gains on the racetrack where you need