Nasir, M., Febriano, H. and Balisranislam, B. 2021. Effect of the Using of Racing Exhaust with variation Soundproofing Material Against Exhaust Emissions and Noise on 4 Stroke Motorcycle. MOTIVECTION : Journal of Mechanical, Electrical and Industrial Engineering. 3, 3 (Sep. 2021), 135-142. DOI:https://doi.org/10.46574/motivection.v3i3.95.