The BMC filters fit better than there rival K&N's, they have stronger outer casings,
and do not fold-in on themselves when inserted into the frame slots.
For maximum air flow use the BMC Motorcycle Race Air Filter - No. 256/19-Race
If not use the BMC Motorcycle Air Filter - No.
K&N Filter Mod
If you do use K&N filters in your '12', this mod will help with the install.
Before you remove the air filters, unbolt and remove the air box covers and put clean paper towel or cloth into each throttle
body, to stop any dirt or foreign bodies going in (will not go passed butterflies).
The K&N filters, early or later type are not easy to fit, so a simple modification with a little amount of grease on the sides,
makes them slide into the filter slots much easier. An angled cut from the bottom front corner allows the filters to slide easily
into the bottom slot in the frame.
Check the air box, between the filters and the throttle body inlet area for dirt, and clean before
you fit the filters, its quite awkward to get your hands in there. I cleaned mine with WD40 and paper towel.
These filters are the later type.
Cut a small amount from the bottom 'front' corner
Rear face of filter
Fit filter into frame slots >>>> front of bike
Filters fitted into frame slots
Stock Air Filter Mod
6-8hp at rev-limiter, 2-3 hp at peak hp when done with Can Mod
Note: you must safety wire the filters if you remove the screens, or the foam will balloon out when the engine draws a lot of air.
This could rupture the foam and render the filter useless. Also the pieces could enter the intakes! Be very careful of dirt in the air box,
this should be checked regularly, it can be a very real concern if there is excessive blow by.
1) Remove the screens from the stock air filters by GENTLY pushing on the screen around the edges. You will see it start to pull free and separate from
the plastic in some areas, once it starts to separate Stop pushing. Grab the edge of the screen and bend it back then tear it like tearing a rag with a swift motion.
2) Clip all small stubs of wire and the wire strands that remained behind. Finger nail clippers work well here.
Time to safety wire the filters.
3) Drill 9 holes 1/16" diameter on each side of the plastic bevelled frame, on the SCREEN side, aprox. 1/2" apart. See Picture
Be careful not to tear the black foam when the drill bit goes through the plastic frame) Drill on the bevel above the glued foam.
4) Cut off 5 feet of .020 stainless safety wire and run it threw the center 2 most holes on each side and then run it back and forth threw all the holes.
Donít pinch the yellow edge foam, with the wire.
5) Take the two ends and run them diagonally back to each other wrapping them LOOSELY to the center of the center most wire.
6) Tighten the wires by plucking them a little and working them so thereís no slack and gently tug on the ends.
7)Twist the wire ends several revolutions to lock them to the center of the center wire, right in the middle of the air filter.
Safety wiring pliers work best, or needle nose.
8) Clip the safety wire ends off so thereís 1/4" of twisted wire. Then bend the clipped end in towards the element so it wont catch
the frame when putting the air filter back in the frame.
The Air Filter