Exhaust – Adding Catalytic converter to Rebel 300

If you add an aftermarket muffler to a Rebel 300, you no longer have a catalytic converter (it is in the stock muffler)

The easiest solution is in this post:

300 Rebel mufflers recommended

AutoZone sells a Flowmaster 2000120 2in Inlet X 2in Outlet Stainless Steel Universal Catalytic Converter for $88.49 USD. It is 8″ or 20.3 cm long.

Akrapovic makes catalytic converters for motorcycles.

Also, you could take the stock 300 muffler to a muffler shop and they could remove the rear part of the muffler and add a 51mm outlet to the catalytic converter section. You could then add an aftermarket muffler (it would need to be fairly short.) It might not look so great.