The po had cut the 1981 kz440 header pipes right after the cross pipe to fit a pair of sito(?) slip on mufflers I want to replace the mufflers with new slip ons but I don't know what I need to worry about. Do I need a certain amount of back pressure for the engine to run right? My budget does not allow for buying a Mac $350 us system so I need to buy less expensive ones and i can't find the same model of mufflers I have now. The bike runs great, I can maintain 120 kph all day with no strain but the exhaust is rusted thru and getting worse. I really don't want to start re-jetting the carbs when everything but the exhaust on this bike is stock other than a paint job. Here in Ontario if your exhaust comes out any other place than the end of the pipe it is considered leaking.
