Just received a large shipment of flex exhaust system to fit the EZM 49cc 4 stroke motor. These have been tested on the EZM kit motors, both the HS & Honda versions. The flex system has been tested and tuned to the EZM motor, it may work on other motors, but I can not verify this as I haven't tested it on other versions of the 49 cc 4 stroke.
Have fun,
Have fun,