Hi there, just found this site and its been a wealth of info. Had a yellow 98 awhile back before I got my 04 Volusia. Now selling the Volusia due to the economic times. So Im trading my boat to a guy for a 2005 S40 with only 800 miles, cant be without a bike! Its been sitting in the garage, doesnt like to idle and has a screaming eagle aftermarket pipe. It was never rejetted, does it need to be?

it will defo need a re jet

There are no stupid questions, just well . . .

The bike runs naturally lean from the factory and the aftermarket pipe will probably make that worse.  However, I put a HD muffler on mine and adjusted the idle mixture screw and mine seems OK. Many times is has been said here, all bikes are different.

It needs to be re-jetted based on this crude summary...

The factory exhaust/muffler is quite restrictive and has more than ample backpressure-backed up exhaust per say.  The stock jets are matched to let the right/small amount of fuel in for this exhaust/muffler.

The screaming eagle or other less-restrictive exhaust/muffler lets out the exhaust quicker than the stocker and back pressure or backed up exhaust is lessened.  The jets in the carb need to be switched out for larger ones that let more fuel in to match the faster exiting exhaust gases.  

Hope this makes sense.  It did to me once I figured out how carbs work.

-Matt

A Savage is always a good trade  

Change the spark plug right away, the tip tends to
"mineralize" when left standing for a while.

With the screaming eagle exhaust you can easily replace
the stock main jet (.145) to something bigger like a (.152)
and go from there, remove air filter cover and play
around with the air screw, about 2 1/2 out should do it.

And yes, this affects the millage since simply more gas
goes through and consumed. The bike is new, a 2005
w/800 miles, are you kidding, that thing should not
give ANY problems in about 20k  
 
Good luck
RP

Finally got it today, 2005 and actually only has 530 miles.