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I just picked up an 04 that has sat for an unknown period of time. It starts, runs, and idles just fine. However, there is fuel puking out the drain tubes the whole time from when the petcock is turned to ON. I opened up the carb found the bowl lined with white crust and dust. I took out the main jet and it was crusty but open. The pilot jet was plugged. Guessing the crust is corrosion, and its all over the insides. Can't believe it runs as well as it does.
I am doing a minor tear-down so I'm replacing and repairing whatever needs to be, so should I clean it and replace the insides with new jets, floats, gaskets? Or should I go new carb, and if so, where should I look?
Keep in mind its for my son, and we don't plan on upgrading from stock just yet. Still running stock pipe and stock settings.
If I stay with stock carb, should I re-jet for something leaner? I keep reading that stock is SO rich. If I'm simply replacing stock jets, should I rejet for something leaner than 32:1, maybe 40:1? We ride between sea-level and 3500ft, and mostly trails, no dunes, and no desert.
Any help is welcome, thanks.

I would just clean it and get a jet block gasket. Check the floar valve rubber piece and he cone portion where it seats.

32:1 is richer fuel than 40:1 as it has more gasoline.

Buy a couple of pilots and mains and adjust the needle clip. Learning how to jet properly will be a great help.

If he is not running it wide open a lot, 36:1 or 40:1 may be enough oil.

Thanks for the reply. Yes, I know that 32 is richer than 40, I was just wondering if changing the stock settings while still running the stock pipe is beneficial. We will be doing more lower end riding due to his ability than wide open, that is why I asked if re-jetting leaner than the stock 32:1 is a good move.

Are the floats bad??

I would throw a 45 plot jet in there as a guess at a starting baseline.

Plug chops would tell if the main is correct.

I run 40:1 Motul 710 in my KDX. My bike used to spill gas like yours until I replaced the float needle and set the float EXACTLY at stock level. I tried all kinds of levels until settling on stock.
I rebuilt everything on my carb. A new carb gets a new slide, which will wear out if the bike has been ridden a lot. I currently run a 40 pilot, 1173 needle and 152 main at 3000' elevation.

I replaced my needle and seat along with adjusting my float height to the exact specification in my manual to stop my overflow leakage. I would use a really fine sandpaper (like 500 grit) to get that white powder off, then give a light coat of 2 stroke oil to help stop it from forming again.

737diesel wrote: ↑02:47 am Jun 19 2019 ... I was just wondering if changing the stock settings while still running the stock pipe is beneficial....

Absolutely. With todays modern oils 40:1 or even 50:1 is entirely feasible and will provide plenty of lubrication, especially if just riding on the bottom end. I have been racing on 40:1 for the last several years with no issues. The main thing is pick an oil, pick a ratio, and then jet to it. If you change anything in the intake/exhaust tracts then you will need to rejet (i.e. new pipe, new top end, etc). Jetting the bike properly will not only make it run cleaner with less splooge, but it will run crisper as well, and be more enjoyable.

Thanks everyone, that is the info I was hoping for.

Bufftester, you're a PNW guy like me, I know you said you've raced a bit but how is your bike jetted?

Stock for the 220 (a PWK33) is 48 PJ 160 MJ. I am running the stock pipe with an FMF silencer, twin air filter, and the KX125 airbox (which is a lot more open than the KDX box with the lid removed) and a top end that is nearing time for a rebuild and I run a 45PJ and 158 MJ but am still on the rich side. Most all my riding is between sea level and 6000 feet, with the bulk in the 1200-4000 range. Mostly it runs great, drips a little splooge, but I am too lazy to chase it right now knowing that at the end of this season I'm redoing the top end lol.