So I was having a look at the OEM air filter:
Cfmoto-motorcycle-kumgang-650nk-font-b-air-b-font-filter-font-b-component-b-font-.jpg
http://detail.tmall.com/item.htm?spm...bf327edc7dd336

See the shape, so then I tried looking for a replacement thinking a K&N Kawasaki ER6N for around 2006-2008 no luck on the K&N site. So I had a look at some other manufacturers and found this:

UploadImages_MC-040-06.jpg
http://www.motospecialties.com/store...mNum=MC-040-06

and this:

P-K6N09-01.jpg
http://www.motorcycle-exhausts.co.uk...l#.Uw_sMrWoXKB

Obviously you can see the Kawasaki version has a notch not present on the CFMOTO version. So my thoughts are will spending money on the Kawasaki version be worth it? Cut a piece of plastic and epoxy it, would it fit? Looks like a little bit of modification. Or just put up with the stock filter? Although China is a dirty place and some tiny particles will always find their way past a low grade filter and a dirty injectors are always a possibility.