4t exhaust temps are lots hotter than their 2t brethren and the packing in those mufflers burns and vibrates.
Motorcycle exhaust packing.
This will result in a louder exhaust and a potential loss in power and performance.
Four stroke motorcycles need a repack too though for different reasons.
Fiberglass packing can be added around the baffle to muffle the exhaust sounds even more.
Thermal zero mpk12 ceramic muffler packing material kit for 2 stroke 4 stroke atv motorcycle dirt bike exhaust silencer spark arrestor muffler packing repack universal wrap 4 1 out of 5 stars 103 17 99 17.