Forget buying another K&N. I've used a small clamp-on chrome pod filter from UNI. Fits with "almost" no cutting.
As you can see, I started cutting up the battery box and frame (wish I had something other than an angle grinder) in order to get the air filter to sit properly. I thought I had it close enough to the correct position the other day after bending up part of the cross piece, but the carb wasn't completely seated in the intake boot.
http://i280.photobucket.com/albums/kk182/motobuddha/74ea4d67.jpgSo first I cut off the part of the crosspiece I'd bent up. That didn't help. It was hitting the battery box. So I cut back part of the box. That's when I saw the filter might be hitting the bolts. Some button head bolts would gain me a wee bit more, but not enough. (There are short screws in the photo, because I got tired of removing and replacing the long ones.)
http://i280.photobucket.com/albums/kk182/motobuddha/6f4933ca.jpgThe filter was still angled like this.
http://i280.photobucket.com/albums/kk182/motobuddha/9b3472cc.jpgSo I've decided to scrap the filter and try this cone shaped one.
http://www.knfilters.com/search/product.aspx?Prod=RC-1250I was hoping K&N had a suitable size with an angled flange, but no.
Again, since I'm using a compact lithium battery, I'll have room for the end of the filter. If I need to, I'll move the rectifier elsewhere, like the inside back of the battery box.