Motorcycles, for the most part, do NOT and have never had catalytic converters. The standard for emissions did not change between 1980 and 2008. Advancing technologies allowed most motorcycles to meet the standard without converters. A few models have had them. The catalytic converter is one more thing to break down on a motorcycle, just as with any additional system. So if you can buy a compliant motorcycle without a converter you are much better off.
Catalytic converters cannot, in most cases, be added to any kind of vehicle for one reason. The fuel system must be designed to deliver a specific level of unburned fuel to the converter for it to be long lived. Too much unburned fuel hitting the converter significantly reduced it's life and performance. Additionally, modern catalytic and fuel control systems use one or more O2 sensors to make sure the mixture going to the "cat" is correct.
Catalytic converters cannot, in most cases, be added to any kind of vehicle for one reason. The fuel system must be designed to deliver a specific level of unburned fuel to the converter for it to be long lived. Too much unburned fuel hitting the converter significantly reduced it's life and performance. Additionally, modern catalytic and fuel control systems use one or more O2 sensors to make sure the mixture going to the "cat" is correct.
