Beautiful bike!
Go on to fiddyforum, sign up, and PM fiddyparts. I'm sure he'll be able to sort you out with one of the FJR88 lumps. They come standard with a IRK kit fitted by lifan and they go really well!
The accel is beast. I love mine.
I guess they are the same size as 50's?
http://i270.photobucket.com/albums/j...r/100_4934.jpg