I am assuming that you do not have the instruction booklet that goes with the carb?
It is pretty easy to do.

1.  Select the size needle that will yield the most power/speed at wide open throttle without faltering from a too rich mix ... probably about a #5.  Needles available from Edelbrock for $12.95 the last time I looked.  The K series needles are a little shorter for a quicker profile.  The E series are longer for a bit longer profile.  The regular needle is ... well, regular.

2.  Then adjust the screw (or knob) on top (the needle has 30 click adjustments ... left for lean and right for rich) for the best low/midrange performance.  To make the adjustments the engine must be off, the throttle turned and held in the wide open position, then you can turn the screw L or R.  The setting is referenced by the number of clicks from the seated position, which is all the way to the right.  Backing off by turning to the Left 15 clicks will get you to the middle position.  Whenever a new needle is installed and you have no previous info to work with then start here.

3. After making the adjustment, start and test run the bike.

The Edelbrock carb, when properly adjusted, will absolutely completely eliminate all backfiring.

I may have some info sheets somehwere and if I find them I will pass it along.

Mine came with my bike so im not sure on the cost.  I think they're pretty pricey and edlebrock has never marketed them for the savage (according to Edelbrock on a return e-mail).  Ithink they make these still for Harleys.  Mine is more than a few years old so I'm not sure if they are the same still.

Backfiring is usually the result of the low throttle range being too lean (pilot circuit on a typical carb), or sometimes due to an air leak in the exhaust system.
The needle size in the Edelbrock is like the main jet size in a typical carb.  That does not affect the backfiring.  It is the adjustment screw which controls the low & mid range, thus the backfiring.  That is like the pilot jet and needle on a typical carb.
If with the needle you have in the carb now, the bike will run wide open with power and NO BOGGING DOWN, then you are not too rich.  Maybe lean, maybe just right, but not rich.  If that is the case, then you just need to adjust the needle.  R for rich, L for lean.  Find the best of the 30 click settings which make the most power/best acceleration and no backfires.

By the way, what muffler are you running?  The Edelbrock will flow a lot of air/fuel, so you need a good flowing muffler for a good match.

Yes, you are thinking correctly.
When adjusting the needle, you can move it 3-4 clicks at a time initially so the process doesn't take a long time ... like you are bracketing it.  When you get the results you want going one way, then back up 2 clicks the other way, then one click back again ... that sort of thing.  That will zero it in for you on the best position.  The last few clicks may take a few trial and errors, until you can hear & feel the difference between the individual clicks, say # 14, 15 or 16 for example.  The changes are subtle from click to click.  That is another reason to use up to 4 clicks at a time initially, it is easier to feel & hear the difference between them.

Regarding the "why lean = backfire" issue ... lean fuel/air mix does not burn as well as a proper mix, sometimes letting unburned fuel out of the cylinder and into the header pipe, pooling there as it were,  which then catches fire moments later and goes "boom"!  Ala BACKFIRE.

Lancer,

I've tuned the carb a bit but now I think I might need a new needle.  I noticed that when I open the throttle all the way the engine boggs down until I back off a little and then it picks back up.  I guess that is a rich condition that is fixed by replacing the needle with a leaner one.  So I have a way lean on idle with a rich on open throttle combo.

Have you put together a good needle, intake, muff combo with the QuikSilver II?  In one of the earlier posts you mentioned a #5 needle but in the book they are numbered 12, 13, 14, 15 and so on.

I have the stock airbox and a dyna muffler.  Not sure which needle is in it now. I read that there are two different needle types.  One is straight cut and the other is curved or spoon shaped.  Any Ideas?

Lancer,

Thanks for the update, sorry about your family's loss.

I am going to take the one that's in there now and pull it out first and then place the order.  The needle size thing makes sense now, and it doesn't seem too difficult to make the switch.  

Ill let you know how it goes.

Thanks again

Called Edlebrock today and talked to the tech there.  He wanted to know which #5 I wanted.  I took the needle out of the carb I have and it is a 6-K.  He said that was a pretty aggressive grind.  So he says they have a 5-K, 5-E and a 5-O.  Can you tell me which one I'll have better luck with?  I'd like the bike to run well and get the best milage possible with this setup.  Not sure what the difference is between the E and O series.

Great news, I thought I had the stock setup on the airbox.  Looks like the stock box with a K&N filter.  Took that out and cleaned it.  Ill oil it back up tomorrow.  It was pretty dirty.  Any truth to the K&N oil fouling things up in the carb??

Thanks in advance.