i have been told the F4i is around 95hp stock. im wondering roughly where that stands in comparison to other Hondas like the 600rr and a few other Honda models?

 

Up to 06 the CBR600rr advertised horsepower was about 115BHP, the 07 advertised was 120BHP.

Keep in mind that these numbers are 100% B.S. On a Dyno a stock F4i runs right around 90 horsepower, if that. My friend's 05 CBR600RR dynoed at 98HP. I just dynoed a guys 06 GSX-R600 and it hit 103HP (advertised 118). Our dyno was just calibrated, but most customers tell us we read low (many shops cal their dyno's high to make the numbers look big for customers, or worse never cal them at all).

With a 2bros slipon, K&N air filter and a powercommander my F4i dynos at 96.8 HP. This winter I'll be hopefully shaving the head, and cleaning up the heads. I'd really like to break 100HP. I fear I'll need a set of HRC cams for that though (big dollars and hard to get).

Dyno numbers are a little low due to the fact there is no ram air on a dyno. I do not know how much the ram air system adds, but I'd doubt its anywhere near 10 HP.

 

 

kawasaki RR seems too have the shortest time for peak hp output.
nice!

 

did "sport rider" dyno these bikes or did they just get numbers and/or HP curves from the factory and plot them on a chart?

 

i'm pretty sure they dyno'd each group of bikes under the same conditions

 

No one metioned whether the factory rates the power at the crankshaft, output shaft, or back wheel.

I have heard that it is almost never at the back wheel. Some people have even speculated that it is actually at the crackshaft not accounting for any of the gearbox losses. [sm=smiley23.gif]

 

Dyno'ed bikes are taken at the wheel. What happens is the factory produces a prototype or a couple for testing. These bikes are where the numbers come from. They are highly tuned though technically stock. They are the bikes given to the media for testing. That is why magazine power is just about bang on the advertised numbers. You will notice that every company uses the disclaimer "specifications may change without notice".

Your bike won't dyno where the magazine bikes will trust me. Sport Rider magazine does not go to a local dealer and buy a bike. They are given them by the factory for a certain amount of time. My F4i ran about 92HP stock (I dynoed it when I bought it). After my mods it ran 96.8HP. So after about $1500 plus in mods I am running advertised power. Keep in mind too that atmospheric pressure, temperature, humidity all play a role in the numbers as well, espescially since all sportbikes use ram air induction. When the factory dyno's the bike the conditions are perfect.

 

Technically brake horsepower refers to the flywheel or engine-only output, but yeah, you're right. Honda has temperature, humidity, and density controlled dynos like most large vehicle manufacturers. I wouldn't be surprised if they also have it setup to utilize the ram air to further improve the on-paper numbers.

 

My bad you're right! Got mixed up Brake horsepower is engine only.