Please educate me

[mikeo]

When and/or why do you re-jet your carb when you go to a free flowing exhaust?
Can changing your exhaust from free flowing to more retrictive make your bike run leaner or richer?
I don't understand how exhaust effects the intake.
I understand that giving your carb more air changes your fuel mixture and that is why you have to re-jet. Thanks in advance for your help

 

[DAB]

Here somewhere to start for general info:

http://auto.howstuffworks.com/question172.htm

 

[Revlis]

Just remember that the Busa uses #6 Primary Jets with just about any new Pipe. Don't worry if your tuner looks at ya funny, tell him. "Revlis Said."

The basic concept though is that any time you make a change to the amount of Air available to your engine, you must then make changes to the amount of fuel available to your engine. If you increase the available air without increasing the fuel you can get a pretty "lean" Engine that runs kinda poopy and hot.

Riding in the rockies on a carburated bike served as a prime example of running too rich. As I climbed to about 10K feet, my carburated bike set up well for 5K feet started bogging down and sputtering with heavy throttle inputs. This is the result of Too much fuel not enough Air. Fuel injected bikes can deal with this better than carbs, and is part of why F.I. is so popular, the ability to precisely control the amount of fuel being fed into the motor based on the amount of air that is available.

Most modern motors come outta the factory running a little lean already for emissions reasons (So I have heard). So you need to consider this before doing anything too radical to your motor. This is also why it's a really good idea to have your Bike professionally tuned when installing a full exhaust system. It's also why it's a good idea to perform your airbox mods, or replace your filter with a high flow filter at the same time so you don't have to make repeat trips to the tuner. If your bike is fuel injected this is where a Power Commander and a custom map comes into play or if it's carburated the need to re-jet possibly. All of this is to get you bikes fueling set up to provide the optimum Fuel/Air Ratio to produce maximum power across the RPM range.

Or something like this... Hell what the Fug do I know? I'ma fuggin Graphics Guy.

 

[mikeo]

Thanks guys