415H-110L Chain with Connector Link for 49cc 60cc 66cc 80cc 2-Stroke Engine ATV Mower Motor Bicycle Motorized Bike Chain Buyang Heavy Duty High Power Racing Parts

First, you need to lose the cheap chain, get a real exhaust gasket. Post some pics of your sprocket and chain and your exhaust flange. The more you show the better chance someone has some answers. I posted a link to a chain. https://a.co/d/04FFwRcG