Last February I bought a 2003 Lowrider.
It had SEII mufflers on it, but they were "gutted" i.e. no baffles.
I rode it all year last year, I ran perfect. It's a great bike, but I wanted a more mellow sound than the straight pipes gave me.
While she's hibernating over the winter in my garage, waiting for the arrival of spring, I installed a V & H Big Shot Staggered exhaust system on her.
Reading posts on every HD forum and web site, I felt the need to pull the carb and see what size jets were in it.
It is the standard Keihin CV40 carb, and I believe it's already been tinkered with before I bought the bike.
One thing that tipped me off was that the cap that's supposed to be pressed in over the idle mixture screw was already gone.
I pulled off the float bowl and the low speed jet is a #48 and the main jet is a #195
A couple of articles I've read say that I should go from a #42 jet to a #45 low speed jet in and from a #145 to a #165 main jet.
The jets that are in there are already bigger than that.

Here are my questions:
Are these the stock jet sizes?
If not what are the stock jet sizes?
would I be better off putting in the smaller jets and use that for my baseline runs?

 

If you're talking about some time on the dyno, what's in the carb to start with really doesn't matter if you're off a little one way or the other. You won't really know what's up until the first pull.

 

My apologies, I should have worded imy thoughts differently.
By baseline runs, I meant how the bike responds when driven.
Such as does it have a lot of decel popping?
Does it backfire thru the carb?
Does it accelerate or or just bog down?
Do the jet sizes that are in there now (#48 & #195) sound reasonable?

 

sounds kinda rich to me, stock jets were probably 45 & 190, but if it don't foul plugs and runs good, I'd be inclined to leave it alone

the 42 slo and 145-165 mains were what evo's had in to start with.... if I'm not mistaken, all twin cam carbs had 45 & 190

 

If you follow everyone's opinion about such things as jetting, you'll be frustrated. What a bike does on a dyno and how they actually perform in the real world are not always the same.

You really should have "something" in your mufflers for better overall performance but I'll avoid opening that can of worms.... Whatever set-up you end up using, the only way to correctly jet one is by doing a proper spark plug "read."

I won't waste time explaining the science or evaulating the art, but ths will get you real close:

http://www.cyclespot.com/Jetting.html

PS A couple of articles I've read say that I should go from a #42 jet to a #45 low speed jet in and from a #145 to a #165 main jet.
The jets that are in there are already bigger than that.

Those sizes are about right for a Sportster and on the lean side for even an 80 in. Evo