2 stroke motorcycles generally produce exhaust emissions that are less than perfect and cause increased air pollution. To reduce one of them by modifying the exhaust using a filter with natural fiber as an alternative material. This test is carried out using a gas analyzer and dynotest to determine the results of the emissions produced and the performance of the vehicle. The results showed that with a maximum rotation of 8000 rpm the lowest CO content was obtained from a mixture of 50% coconut fiber, 35% mother-in-law's tongue fiber and 15% hibiscus skin fiber with a value of 4.04%. The lowest CO2 was found in a mixture of 50% coconut fiber, 25% mother-in-law's tongue and 25% waru coolie fiber with a value of 2.46%. The highest O2 was found in a mixture of 50% coconut fiber, 25% mother-in-law's tongue fiber and 25% waru coolie fiber with a value of 12.28%. As for performance, maximum power and torque are obtained in the third specimen with 8000 rpm rotation of 11.03 hp and 10.55 Nm of torque. Meanwhile, the standard exhaust gets a maximum power and torque of 10.92 Hp and 10.40 Nm of torque. From the research it can be concluded that the three specimens are the best to be used as filters to reduce gas emissions produced in vehicles.