I am new to the board and am looking for a CBR600 f4 or F4i. I'm not new to riding though as I raced motocross for many years and logged several thousand miles on my old CBR600f.

My question:
I've test ridden two F4is and two f4s and it seems that in a certaint rpm range the F4 has more of a hit to it than the f4i. Maybe the f4i was a little more responsive down low, but as the rpms climbed the f4s seem to have a clearer spot were the powerband comes together and gives you a good tug. To the point were it actually lofted the wheel a couple of times in 1st. The F4i pulled evenly but never actually "hit", it just seemed to rev past the same spot with no defenition. I know in test reports honda clamed a 5% power increase from the f4 to the f4i. Where is that extra power or is that just marketing BS?

Or am I just crazy?

more than likely the F4i's power delivery is smoother throughout the entire power band and more power at lower rpms, so your not noticing a 'jerk' at a certain speed, your probably going just as fast or faster, but just smoother. plus its hard to say you there were any adjustments to either bikes that you did/didnt know about (sprockets etc)

All bikes were stock except one f4i had a micron slip-on. I will admit that I did not count the teeth on the sprockets, even though the owners siad they were all stock.

I think the RPM range was around 8k were the f4 would pull pretty hard. Like you said it may be that the f4 is delivering its power in one spot while the "i" was spreading the same power over a wider range.

But either way the F4 felt faster, even though it might actually be the same.

i dont forsee a F4 being faster than the F4i if they are both stock, otherwise why would honda spend all the money on R&D to make a slower bike?

im quite confident that its just smoother, and you dont notice the power kick as much.

http://www.mcnews.com.au/Testing/Honda/CBR600F4i/Page1.htm;)

F4i's can loft the front wheel too... My stock did it in first at ~7k

Stock sprockets on an F4 are different to the stock sprockets on the F4i. The F4i's got 500 more rpm at the top so they made the gearing a little taller to take advantage of this.

That, plus the whole FI/Carb thing is probably what you're feeling.

^ thats exactly it. the f4s are carbureted and they tell to give off instantaneous power with a jerk like response. as where fuel injection is a bit more linear since all throttle pulls have been preprogrammed.

i remember that the 01 f4i has some problems with the pgmFI and the low clock speed on the processor caused the bike to have a slight hesitation when the throttle was pulled abruptly< I will vouch for this since I see it on my bike. however, they claimed that the fixed the that issue with the 02s and up. over all, you should see a quicker response from the throttle on a carbureted machine. since FI processes do take up time to respond according to what they where calibrated for.

I didn't like that little bit of hesistation my F4 had; the F4i's acceleration is definitely smoother.

On the other hand the F4 looked better. I'll never like the headlight's low-beam set-up with the F4i -- it's a stupid design that unfortunatley didn't end with the latest RR.

My cousin had an F4 and i have a F4I, When he rode my bike he said the same thing that his seemed to have more pull but also said that mine seemed faster in the top end than his did.

Yes the headlights suck on the F4I's I mean how many times do i have to explain to people that i don't have a burnt out headlight. Although i do like the look of the headlights better than any other, i just wish they would work like the R6s rather than one out when not useing the highbeams.

I want to know why the F4i is geared +1 STOCK compared to the F4 :eek: [sm=smiley25.gif]
STOCK
F4 = 16/45
F4I=16/46

Like I said in my post above....

it's to take advantage of the extra revs the f4i has up top.

im not sure what power on top you guys are talking about. clue me in.
both bike produce their peak power around 12.5k rpms. after you reach the peak its all down hill from there.
however, I recall seeing on bikez.com and somewhere else that at 10k rpms the f4 has about 3-4lb of more torque. thats a pretty good difference. I recall that the f4i has 46lb and the f4 has 50lb or so.

Its not so much how much peak power it has or where it is on the dyno chart, but about how it delivers it. The F4i is a little bit more linear, while the F4 tends to spike a little more towards the top end, making it *feel* like it has a stronger top end. From what i've heard they're very very similar, but the F4i has a slight bit more midrange. But i don't have a dyno of each one in stock form to prove it.

But here's some data according to motorcyclistonline,com:

CBR600F4 ('00)94.8hp @ 12,50044.8lb/ft @ 10,00011.61 @ 115.9mph6.76 436lbs wet


CBR600F4i ('01)95.5hp @ 12,50042.6lb/ft @ 10,25010.71 @ 126.7mph 4.12 435lbs wet

The engine output is practically identical, but the 1/4 mi times are not. I'm guessing it's the gearing or additional overrev of the F4i that makes the difference...? Or perhaps the midrange pulls it through the gears a bit faster...i dunno.

Actually that may be bad 1/4 mi data for the F4. Here's the previous years stats:

CBR600F4 ('99)98.4hp @ 12,50045.8lb/ft @ 10,50010.86 @ 124.9mph 4.83 440lbs wet

Looks pretty much identical to me...at least when it comes to power and speed alone. I don't know what other updates were made to the F4i besides fuel injection and looks. I'm guessing it's a slightly different frame, but i could be wrong.

go -1/+2 and it will lift every time! Mine does like 90% of the time or the front will get really light!!!

So it sounds to me the Honda claim of a 5% increase is somewhat BS. It seems like the changes that were made to the engine in 01 allowed it to overrev a little more but cost it some tq in the process. Any one else jump fom a F4 to and F4i or visa versa, or has raced similar F4 to F4i?

So far it seems on engine performance they are very similar,I guess the decision will be based on handling, looksand price.