I have a '03 and was thinking about porting the stock intake, I've done the stage 1 exhaust mod and it has a K&N filter in the stock air cleaner. The bike runs fine as is and I don't want to create a problem but my wife rides with me most of the time so a few extra ponies and some added torque would be nice. So my question is, would this mod require the carb to be rejetted ? not sure I want to take that step if it does.......

No, it will not need rejeting.

As said porting alone will not require jetting changes.

cool, thanks for the info.........

Only in the sense that mods are addictive like lays potato chips. Once you've done one....you will end up doing something that will require a rejet eventually. But just a manifold porting...no rejet.

Therein begs the question...will a ported manifold alone result in any horsepower gains?

Father Pobasturd wrote:
Therein begs the question...will a ported manifold alone result in any horsepower gains?

Could not say if there are any horsepower gains, but the torque curve in the midrange makes notably more pull. The CV carb will respond to whatever the engine is gulping in, and meter accordingly.

Something I don't understand about porting. If you do this and it doesn't require a jet change it makes me think you are not doing anything. Is it a placebo???

Going to disagree on a few points here.

In your case, stock air box and minimal changes to the exhaust, you will most likely slide a little rich. Probably not a real big deal, just realize that possibility exists (it will absolutely happen, just may not have much practical impact.) If you don't have an aftermarket jet kit, you won't be able to do much anyway. Even if you did, we don't have a lot of collective experience for this scenario.

If you had aftermarket air kit and exhaust, rejet should be expected and normal. The more radical the porting job, the more you would need to do it.

Porting manifolds makes mix potential more efficient. So counter to what you may think, it requires jetting down and reducing gas flow into the main jet. My typical while I was porting manifolds was usually one jet size down (yes down) on the main jet when using Mikuni jets.

Be aware and get some good recommendations if your ever change out both your air kit and exhaust.

Agree with Gram it is a total waste of time to port your manifold if you have a stock intake and pipes. Good to see you on Gram!