since I've see a lot of guys asking how you take the air filter assembly apart and there is no how to yet, I guess I'll give it a go.
this is focused only on the foam filter and assembly itself. assuming you know how to get the filter in and out of the airbox.
tools:
1. drill
2. 1/8" drill bit
3. rivet gun
4. 3 - 1/8" X 3/8" rivets
other supplies,
1. foam air filter oil
2. a detergent such as dish detergent or filter cleaner.
3. gloves(not necessary but keeps hands clean, the oiling gets messy)
ok lets get dirty....
1. step one is removing the rivets. using a 1/8" drill bit drill down the center of the rivet to remove it.
2. next seperate the housing and faom.(these will lift apart very easily)
3. cleaning, Clean the housing and filter. make sure you get all the metal shavings out of the filter and off the plastic housing and screening. this is very important!
cleaning the foam is rather simple and I should not have to get detailed with you about it. basically soak the filter in warm water with a detergent and knead the soapy water into the filter.
repeat until you are happy with the results.
next dry the filter as much as you can with a towel or paper towels. and now let it air dry completely.
while you are waiting for the filter to dry wipe off any dirt on the filter housing and in the airbox.
TIP! = to help keep the filter even cleaner apply a thin coat of grease to the inside of the airbox in front of the intake tubes. and on the airbox lid.
most of the dirt will be stuck to it instead of the filter.
4. oiling the filter. you can use what you want. I prefere the peace of mind using real foam filter oil by UNI.

now oiling the filter is messy. you can put some oil in a bag and do it that way but thats no fun! this oil is very thick and probably would not work too well pouring it in a bag and kneading the oil into the filter
I like to put the oil on my hands and smear it over the surface of the filter. and then knead the oil into it.
make sure you cover the surface of the filter completely. try not to over oil it. if you think you over oiled it just soak some of it back out with paper towels.
5. assembly.
place the filter over the bottom (screen section) of the housing.
place the top frame on that.
now insert a rivet in each hole.
the next step is assuming you already know how to use a rivet gun. push the gun down so the housing is mated together and rivet the housing.
(to use a rivet gun, you need to slide the gun over the shaft of the rivet and push the gun down seating the rivet tight to the surface you are riveting. when you squeeze the handles together it will snap the shaft of the rivet.
thats it you're done) easy right!
this is what it will look like when you are done
DONE! super easy!