other than the fact that one is fuel injected and the other one is not... what is the difference in performance of the bikes?

 

i think the f4i has more hp...not 100% sure tho.

i'm also very curious.

 

I went from and F4 to and F4i. In terms of strictly engine performance, slightly more hp, better throttle response (result of fuel injection and many other minor upgrades). The appearances are slightly different, f4i has the different nose section with separate lights , it has a two separate seats as to the f4's long one seat, it weights a tad less also. There are over 100 little changes they made when they redesigned the bike but nothing is major and noticeable to a standout degree.

 

Here is an excellent article detailing the differences between the F4 and F4i:
http://www.esatclear.ie/~apark...x.htm

Click on "Improvements"