Well look no further you've come to the right place.
I compiled a list of things I believe should be done when you get your new to you bike.

Note: if you're new to the KDX, you ought to know this:
A: 220 owners: sorry but you must replace the stock piston, they WILL grenade.
"But, but,...I ride it gently"
it doesn't matter.
"But, but,...it only has 1 hour on it.
IT DOES NOT MATTER.
They will unexpectedly break with NO warning.
Don't believe me...go there:
http://www.kdxrider.net/forums/viewtopi ... 77&t=12419
and there:
http://www.kdxrider.net/forums/viewtopi ... 77&t=11380
You've been forewarned.

you will need
manual + torque wrench are strongly recommended
gasket kit: $19.99
piston kit: $126.99
wrist pin bearing: $12.99
coolant
total: about $160
B: a few things to watch out for when doing a top end (200 and 220 alike)
To remove the cylinder, you need to take apart the kips actuator.
Before going hulk on the nut holding the "claw" (16085; 782296 $69.30):
Warning #1 You MUST support the shaft (13234A: SHAFT-COMP,GOVERNOR 768521 $67.77) when removing the 6 mm nut (92015A; 858088 $2.92).
Warning #2 This nut is left threaded (opposite of what it usually is)
If you don't, you will weaken the (13236) LEVER-COMP,GOVERNOR (768746) $8.26, if that part breaks it could destroy your clutch basket and other main gears
http://www.kdxrider.net/forums/viewtopic.php?t=5017
pictures are missing but this explains what else could go wrong when the pin breaks...(ask me how I know

OK, now back to topic, bare minimum maintenance:
1: replace tranny oil
2: put fresh gas with your favorite oil at your preferred gas/oil ratio
3: check air filter: clean and oil accordingly
4: check brakes (play and shape of pads/disk)
5: go ride
Now that you got that 1st ride out of your system, time for some more in depth maintenance:
6: get a manual: that's your best tool (along KDXrider

7: put a fresh plug
8: clean carb.
9: jet your bike. Not only is it good for the bike, it's the cheapest, easiest thing to do to get the most out of your bike... "free power"

Nobody else but YOU can do the work (unless you can pay someone to do it...)
OK, I can hear it already

"But, but,... I don't know how to"...
"But, but,... it's hard"...
Ok now pull up your big boy pants, quit your cryin and go there

http://www.kdxrider.net/forums/viewtopi ... 105&t=1156
10: inspect all levers (clutch and brakes) and adjust for play
11: inspect all bearings, clean and grease them. (wheel and most importantly all swing arm + linkage bearings)
Pay particular close attention to the bottom shock linkage, they are prone to rust and fail much faster than any other.
Note: Using good quality grease will save you time and money in the long run.
I use to get cheap bearing grease from the local hardware store; it does the job fine but after getting some real bearing grease (like bel ray) I'll never go back. That stuff last twice as long and is actually pretty hard to get off.
12: replace for oil.
13: set up your suspension:
http://www.kdxrider.net/forums/viewforum.php?f=102
Got a bit more dough? Here's what I'd do next:
14: get the proper spring for your weight, it will make a world of difference.
It'll make the ride more enjoyable, safer, improve your confidence and skill set. You will get faster... drum roll please.....: faster

15: get your shock rebuild (or rebuild it yourself) or at lease a nitrogen charge.
more later.
please add whatever you think should be on this list.
I'll try to have a complete list stickied later.
I think this would be beneficial to all the new member...
thx
gear box OIL:
Most use a full quart. (+it quiets down the "KIPS rattle")
10W30 and 10W40 car oil works fine.
Same goes for motorcycle specific oil, just be sure it is for wet clutch use.
I've found that some brand work better than others (same weight), so you may have to try and see what works for you.
It may take 1-2 oil change to see the real difference from 1 brand to another.
DO NOT use any oil that says 'energy conserving' on the EPA tag on the back of the bottle. It has friction modifier and will mess up your clutch.
Some like ATF type F (Automatic Transmission Fluid) and swear by it, some hate it.
I change the oil quite often like every 4-5 rides (oil is rather cheap), some do it once a season, it's whatever works for you.
I think it depends on the type of oil you use and how hard your ride the clutch. I can tell when it's time for a change on mine.
next: some CLUTCH inspection and work...to be continued...