421cc developed Custom Exhausts

These 2-Stroke expansion chambers are designed and developed with the aid of our bespoke exhaust design Software and in-house load cell Dynamometer.
These pipes have been designed to suit the Athena 68mm Cylinders with a +4mm stroke crank
Special welding processes have been developed to give an exceptional weld quality on Stainless pipes which makes for a perfect finish.
These pipes are the Standard 'one up either side' layout, pipes are made to order.
Please email for manufacturing times

421cc developed Custom Exhausts