Motorcycle Repair: Altering the exhaust system, honda shadow spirit, honda shadow spirit 1100

Question
I was told by a Honda service manager, that I would not get any real performance out of my 2001
Honda Shadow Spirit 1100 by just putting 2" Cobra
drag pipes on it and having it re-jetted,in fact I may loose fuel mileage ...Is this true?.. Also if I were to remove the stock muffler baffles would I gain anything but noise and would I have to re-jet if I did remove them ? And lastly, if I just put a K&N air filter on my bike would I have to have it re-jetted? Thank You...  

Answer
Hi Rich,

I agree with the service manager.

The performance parts would shave some weight from the MC, but loose some reliability in the process. Trying to get the air-fuel mixture (jetting) correct with the new parts would be difficult and time consuming. It actually de-tunes performance, though most people don't notice the difference. They enjoy the sound.

ANY changes to the air intake, exhaust, or fuel means the carbs will need tuned.

Respectfully,
Mark Shively
Mark Shively