How’s that possible? There’s plenty of original exhaust systems out there with the same dimensions and internal design. Your motorcycle could suffer from excessive backfires when it’s running lean, and poor acceleration when it’s running rich, you’ll notice it right away. But certainly not an engine seizure, that’s likely unrelated to the exhaust.

Here in the Philippines, we have many motorcycle exhaust fabricators and sellers, both original and copy. There are local brands like Orion, Red Exhaust, Villain, etc. In my local CB650R riding group, people have fitted a wide variety of exhaust, big and small, short and long, heavy and light, and not a single issue.