bad man, lose some strength in bike better to get it axle machined sorry but i hope i am wrong, i will wait and see if some one else has done it but thats what i am thinking
oh right that could work but might make the wheel a bit unstable, I'd try that before trying to cut up the swingarm, but a piece of metal pipe would be better if you can find one
just die grind your axle to suit...it ll be ok....like ya said its only a fly sht top and bottom....
the 12mm and 15mm swing arms are the same its just the axle slot that is different.