yup pops racer is correct. Main must be set first then lowend then idle. Another way of testing if your low end is correct is the odle test. I find it works better but that is my opinion.
To do the idle test do a speed run(after main is set). Then after you get to WOT and you're at top rpm let it come down to an idle. Let it idle for about 5-7 seconds then NAIL
the throttle. Thatrs right, give it WOT and nothing but. The take off will tell you whats up with your low end. If it bogs, 4-strokes a little, or makes big puffs of smoke and looks like it is stuggling to get to speed then your low end is set too rich. In that case you lean about 1/8 of a turn maybe more maybe a little less. If you nail it and it misses or almost quits then you are too lean. A overly rich low end wll make your car load up very fast. A too lean of a lowend can make an engine idle unsteadily make it (speed up and slow down) and most importantly it will cause it to overheat.
Pops mentioned that it should idle for at least 30 seconds. That is correct for hard running and or bashing. I myself set mine to just idle much much longer than that. I do that so if it gets stuck on something, I dont have to blimp the throttle to keep the chamber from loading up. It's also fun to let it idle for a min or 3 and then nail it and it takes off very strong without bogging or missing. Yes it does smoke alot but it takes of like crazy fast. Another advatage, you can put your body on or set your shift point or do other minor things and not have to worry about it stalling. But do go for atleast 30 seconds. Be very patient too. Make sure your engine is up to proper engine temp before attempting to tune it. After you make a needle adjustment, run it a little while to let the new setting work. Even if it takes you days worth of running, tune untill youve got it right. there isnt anythign more frustrating then having a engine running bad and having to tune everytime you run it. Tune it right and forget about it.