General Exhaust Question

[ATC#22]

I am looking to get a new exhaust setup for my motorcycle (and possible in the future for my ATC) and just had a question. So I have heard that you must tune your carburetor if you replace your exhaust with aftermarket to compensate for the demand of air intake power from the new muffler. However, its just the header pipe that badly needs replacement on both my ATC and motorcycle. Since I ride my street bike more I figure I will replace that one first and see how it goes. My question is if its just the header (downpipe) exhaust part I'm replacing that won't need a carb tune will it? The only difference is it's stainless steel (so no more rust) and is fitted to be like the OEM part. It even allows for my original good muffler to be connected. So If I keep the old exhaust muffler and just replace the header pipe I won't need a carb tune right? Thanks.

[Doink]

As long as the length and ID haven't changed, it shouldn't need any tuning. Often overlooked is the shape. If it bends less than stock, you'll get better flow and may need a tuning. You say it's fitted like OEM, so if the bends are the same you should be OK.

[ATC#22]

Ok thanks a bunch saved me some time and money.