Aftermarket exhaust and jetting

I'm considering an aftermarket 4-1 exhaust system for my '81 KZ550C (LTD), mostly for aesthetic reasons (the chrome on the stock header pipes are rusted). If I do this will be need to re-jet the carbs? I'm keeping the stock intake system.

Thanks for any input.

I would recommend rejetting. The aftermarket is going to flow more air than the stock exhaust and since an engine is a big air pump then more air going out means more air coming in. Therefore you need more fuel. Plus carbs are generally jetted lean from the factory so an aftermarket exhaust makes things twice as worse.

I've installed several jet kits on bikes with stock exhaust and there is a small noticable difference but it is there.

Later, Doug

I was thinking about pipes on my 550 also, I just installed pods and had to go to 95 mains and a .5mm shimm under the needles and one turn on the pilot the K&N manual said about 10 percent so probably start at about a 98 main and run it then check the plugs, if you dont know replacement jets for the tk carbs are kiehen small round. I dont think you will get any hard numbers for jets due to so many differebt factors from bike to bike and elevation, humidity ect. What kind of pipes are u thinking about