Here is my story.... about 6 months ago I bought a used f4i completely stock with a little rash nothing major.... I paid 3k for this bike and sold a r6 to get it simply for a more comfortable bike... at this point the difference in power was no big concern so I test rode it and fell in love with the smooth ride and less aggressive riding position. The main reason I am posting this is in hopes that it may help someone... From day one this bike never really felt right as far as how it ran. It surged at anthing over 5k rpm in 5th or sixth and had a sort of sloppy sounding idle almost like it was missing a cyl. or 2 at idle up to 3k rpm or there abouts. what really bothered me was this top end surging. this was after all wher most of my time is spent while riding. I tried what I beleive to be everything to resolve this problem. I put a 2bros slip on on and it got a little better so I got a power commander to make it even better. But it never really went away. So in my head I narrowed it down to fuel pump or injectors... NOW by this time I have been through 2 sets of plugs, new coils k&n filter not to mention a trip to the dealer for a little trouble shooting. Yes I do need new injectors ar at least replace one and I now know which one it is, cyl#1 due to a dirty gas tank which has probably messed up all the injectors to some small extent. BUT this is not what caused the high end surge.... On sunday I pulled Plugs(as of yesterday I am on my 4th set and replaced them with NON irridium)by method of tank removal so I could access the injectors and service the k&n. This is the first time I removed the airbox and stacks(here is where it gets good). The stacks are staggered so I took note how they came out BUT when putting them back I noticed that someone had removed them before and put them in backwards... yes backwards y'know left was right and right was left. There are little tabs to insure they go in the right way but someone just put them in and crushed those little tabs. Let me tell you that this is a totally different bike now and the surge is gone it even sounds different.... it is louder and much cleaner sounding. I still have the bad injector and will change that next... Soo if you bought a used bike and are having this problem this may be something to check. BTW even the dealer did not find this... not to insult them but it just goes to show how a simple thig can drive you nuts

 

You mean that the tunnel rams / velocity stacks made that big of a difference from just being in the wrong spot? Wow, I would've never guessed that, but it usually is the simplest things that seem to be the problem.
How do you like the F4i compared to your R6? Any difference in handling or power besides the seating position?

 

both are great bikes I wish i coud have kept both

r6
more power
handled better at high speeds

f4i
smoother ride
manuvers better at lower speeds (80 and below)

both have strengths. as I get older I just don't bend as easily
oh yeah most important the seat is much more comfy.
had an 01 r6
the f4i is an o1 also

 

what year R6 did you have?
from my experience, F4i stable in turns and straights at all speeds...R6 felt too light but easy to throw that schiznit down in the turns...like a biatch.