Change exhaust - rejet necessary?

[Twisted]

Here is a pic in natural light -

[Big Rich]

Im on my phone now so i can barely see the pic but it still looks whiter than it should be. Maybe someone else will chime in?

And for future reference, the best way to check the plugs is doing a "plug chop". Pulling them out after the parking the bike will give you an overall idea of what your jetting is, but chopping them is much more effective.

[thatshitcray]

The bikes already run lean from the factory, so you wouldn't really want to do anything to make that worse, but if you're leaving the stock air filter in you can usually get away with putting an exhaust on a bike. Yes the exhaust lets air flow out faster, which potentially could lean out the fuel mixture even more, but if you still have the stock air filter in, and it's not letting any extra air in, well there's not any extra air for the exhaust to let out. If it does increase the airflow and your plugs look like it's running too lean, just put some duct tape over a chunk of the air filter to cut back on some of the air. 

Old thread revival!

This answer.. If the exhaust in blow out more air, and can't suck in more air, would it be able to suck in more fuel. Or is that only possible with a rejet. 

Is the post correct, and you can get away with just changing the exhaust, things might be a little out of wack but okay..?

[The Buddha]

The exhaust is the most restrictive thing to flow as the bike rolls out of the factory, and its a hair lean to start with due to EPA.
The stock bike needs a rejet.
And well, you're taking out the biggest restriction as it stands, but the 2nd obstacle is close behind - the airbox. Having said that, we rejet the stock bike and one with a slip on or even a full system the same. An overall +1.
Take out the airbox and pipe and you're at a what +8-10 on the mains.
Some people take out the airbox but leave the stock pipe. I have never done that.
Cool.
Buddha.