The way I am reading it, no he cannot. To get the KFF he has to be in mega armor. A model in mega armor cannot be on a bike if you look at the fine print.
the reference that i have here (7th edition ork dex in pdf format),
says that a big mek may exchange his slugga for a KFF 50points.
put him on a bike and follow your nob-wagon around until it breaks and you fix it with special gifty toolz, then sprint back to the slower center of the line and cover the morkanaut while you do your fixing up... no?
i have looked for this on teh webz, and found... [emptiness]
lost in the warp.