I stand corrected on the size of the F4I as it is a 1/4 and not a 1/5 like the R1. The R6 is 1/6, which further reduces the rotation than the R1 tube.

For more info:
http://www.gixxer.com/forums/showthread.php?t=213953

 

Just wanted to clear some things up for those that want to do this for their f4i. It is possible to fit the 1/6 throw R6 tube (part # 2CO-26240-00) on the f4i without having to buy 1krr switches or anything like that. Everything was left stock except the new tube

You will end up having to trim the tube itself. I bored out the throttle housing all the way around and the tube was still too big, the housing would not screw together. So grind the tube to about the size of the stock tube, but leave the cable holes and route alone, just trim the outside portion.

I had to release slack from the throttle body, which is more work, but I didn't have enough adjustment up top to do it. Make sure that the throttle opens and snaps back into place easily. When I first installed mine the throttle closed slowly because the cables were too tight. I adjusted more slack out and now it snaps back nicely. Also be sure to check this with the handlebars in all different angles