Should be 140ish now...but there is more you can do. You can get a Vortex sprocket set with 520 conversion off ebay for prolly around $140...maybe less. But even so, you lose some top end with the sprocket...course it's not like your red-lining in 6th gear, but the only think that can overcome that resistance barrier at top speed is horses...whether you get them by trying to be at a higher RPM range with gearing, or try jetting, K&N, and a full exhaust to get a few more horses out of the engine...I dunno. I know my 94 has just a V&H slip-on, no jetting, stock gearing, and it will get 142-144 consistently...and I have heard of F2's in the 150's...and I have heard CLAIMS of F2's in the 160's.

 

Here is a link that I like to mess with. It calculates the rear wheel H.P. needed to achieve a set M.P.H.
Honda CBR F2
Coefficient of Drag (Cd):.600
Frontal area (sq. ft.):5.98
wet weight of bike 440lbs + rider

http://www.rbracing-rsr.com/aerohpcalc.html

F2 produces peak h.p.(around 84)from 10,500rpms to 11,000rpms, so to achieve the best top speed You want to be at 11,000rpmsat top end.

 

thanks guys

 

When I bought my F2 at the end of last summer the guy I bought it from told me that the front gear was down a tooth. I haven't really ever verified this but I will look at it this weekend. What's the stock tooth count on the front?

Additionally, after reading many of these posts I see people saying that 140mph is the current top end? Or is that if you're down a tooth on the front? I ask this because I have hit 140 at least twice now since I had my bike and it felt like it had quite a bit of room left to run with. Am I on crack thinking that?

 

The stock front sprocket is 15.My old cycle worldmag from 1994 clocked the F2 at 147mph.For this bike to achieve 147mph it would need to put down 79rwhp. A well tuned F2 (exhaust, jetted) can produce 83rwhp. I think with the correct gearing, and alittle aeroadjustments (remove side mirrors, cut down wind screen, tape up cracks, lower bike etc.)You could maybereach 154mph.

 

If I was trying to get the best top end out of my CBR I would go with a 40 tooth rear and 15 front with a 520 chain. That would put me at peak H.P.11,500rpms at 152mph. Also a 40 tooth sprocket will free up a little H.P. being that itssmaller with a shorter chain...

 

that would make the top end faster on your bike but you would loose alot of torque so you would need to find a longer road to get to your new top speed and if you are worried about the little bit of weight you would save by having a smaller chain and sprocket take a crap before you ride.

 

Actually there have been many dyno tests that have shown that going from a 530 chain to a 520 chain (2lbs lighter)gains about 1.5 to 2h.p. and around 3 to 4 h.p. in the mid rpms.

 

I am glad to see someone else say this....I've had the argument a number of times....peak speed is all about HP peak. But the fact is that if you are pulling to redline in top gear, your bike can be geared to go faster, as power peak is usually 1000-1500 rpm before redline.

It all depends on your needs. Drag racers care about making the most of each shift...som believ in using all 6 speeds. I've read books where the author insists you gear for the faster part of the track. For road racing, I disagree...you spend so little time at top speed, that if it comes at a penalty of fumbling with gears in tighter/slower parts of the track thats counter productive.

 

Good points. Drag racingis all about thetake off and 60ft times. Alot of that is mastering the clutch, but a quicker gear is going to get You out of the hole faster. Too tall of a gear and You can't keep the front end down, too long and You'll either bog or burn Your clutch out. Because I lowered my F2 2 incheswhen I launch it hard instead of coming up it spins the rear tire, (I think I need better rubber.)