American Honda introduced the 2001 CBR600F4i to the press at the Mandalay Bay Hotel in Las Vegas, Nevada this week with Gary Christopher giving the opening remarks. 

Christopher, who was recently named as the Senior Manager of Honda's racing efforts, began his introduction of the F4i by reminding the assembled journalists that the F series of Honda motorcycles have been and still are primarily intended for street use. As it turns out, this reminder defines the F4's intent and performance envelope. The F4 is now at a cross road.

When Honda introduced the CBR600 in 1987 it sought to blend the demands of the street with the rigors of racing and succeeded admirably. But technology has advanced at an ever increasing pace and the need to win on Sunday so you can sell on Monday has prompted other manufacturers to build bikes that compromise their street ability in favor of track prowess. The CBR600F4i more closely defines the point at which street-abilty and track prowess cross than any other bike I have ever ridden.

The designers of the CBR600F4 sought to improve the bike in three distinct areas; styling, engine performance and handling. In the styling department the F4 gets some nose work. Its new nose houses two 55 watt H7 bulbs. The left bulb is lit for low beam and toggling the high beam switch illuminates both bulbs. Candle power is up by forty percent.

The ram air intake tracts were changed to house larger intake ducts and their openings are now better integrated into the fairing. In keeping with a trend to lower the coefficient of drag, the turn signal stalks are now shorter but the stalks for the mirrors are higher and wider for better rear viewing. Honda claims these changes netted a 3% decrease in aerodynamic drag.

Although the fuel tank looks identical in shape to the old bike it now carries another .9 gallons of fossil fuel.

The seat has changed from a single unit to two separate pieces which increases the bike's utility by opening up a space under the passenger seat for a U lock or jacket and the single saddle up front makes it easier for the rider to move from side-to-side during quick direction changes.

There is a new look to the cockpit as well. The two analog gauges of the F4 have been replaced by an integrated unit that features an LCD display which keeps tabs on fuel level, speed, coolant temp, and the time. There are warning lights for oil temp, and over-rev (shift light) as well. There is also a delay timer built into the fuel gauge that keeps the gauge honest when you put the bike on the center stand.

The rev counter is still an analog unit but with white numerals and needle indicator on a black face.

The frame and swingarm are also painted black this year and while sitting in the lecture hall listening to Doug Toland explain how this paint was a blend of tiny metallic particles laying at odd angles to each other I chuckled to myself, because it looked just like flat black paint to me. Then I was quite surprised when I saw the bike in daylight at the track and realized that the frame had turned a burnished, almost metallic color that looked ever so slightly like titanium. Pretty cool.

To improve the handling you need more than a coat of paint, though, and Honda made some small but important changes. There are additional stiffening ribs behind the steering head and the cast pieces of the frame where the swingarm passes through. These changes are responsible for 7.4% increase in lateral rigidity and a 10.9% increase in torsional rigidity.

The swingarm got more than a coat of paint as well. The left side is supported by a needle bearing while the right is now supported by a ball bearing and a needle bearing to eliminate lateral play. The swingarm pivot shaft id (inside diameter) was reduced to make it stiffer as well. The lower shock link is now thicker than the one found on the F4.

The suspension damping numbers were changed to get a better feel at high speed. There is more low speed damping at both ends, and the fork cartridge internals are aluminum to reduce unsprung weight.

The front wheel was widened at the hub to improve front end feel, particularly under braking. As the hub grew, it moved the brake rotors out with it. This moved them closer to the calipers which, in turn, meant that the rotors needed less offset. The fork spacing is identical to last year so to accommodate the wider wheel the fork spacers were narrowed.

The wheels, both front and rear, are lighter as well as are the brake rotors. The rear sprocket is now carried by six bolts instead of five. The shock dampers in the rear wheel are much smaller to improve the feel when shifting and its lighter as well. This all adds up to a bike that now weighs 370 pounds dry.

Although the engine is basically unchanged, it would be quite unfair to say that there aren't significant improvements. I'll cut right to the chase here; the horsepower is up by five. Most of this increase comes not from cam timing or valve size but from the larger ram air tracts mentioned previously, an extended red line, and the throttle bodies which are larger than those of the F4's carbs. 

Interestingly, when the air box and tracts got 15% bigger they started to resonate. This resonance created additional noise pushed the limit for noise emissions over the top so Honda added small plastic resonators atop each tract that keeps the honk to a minimum without sacrificing power. The muffler was also reworked internally to be freer flowing and this undoubtedly added peak power as well at the new 14,200 rpm red line.

To provide for the same level of reliability at the higher redline, there are now two valve springs under each valve to insure that the valves exactly follow the cams' marching orders. The cams themselves have larger holes down their centers to reduce weight, a la the CBR929.

Honda was pretty serious about making the F4i rev better and to that end they decreased the flywheel mass, decreased ring tension and enlarged the cross-over holes in the crankcase.

For those of you who may not know what cross-over holes are, let me digress: Imagine a twin cylinder engine displacing 500ccs. When one piston goes down on the power stroke there are 250ccs of under that piston. The cross-over hole links the two haves of the crankcase together so that the air being pushed down by the descending piston helps push up the cylinder in the ascending piston. Think of it as free power.

The transmission got attention as well. The shifting dogs are undercut on the F4i at a different angle and it makes shifting much, much better than on the F4 which was no slouch at cog selection. Also, fifth and sixth gear are closer together which makes the bike feel noticeably faster on the top end. The rear sprocket has one more tooth as well so top speed is about the same as the F4 but at a higher rpm.

Naturally, the big news for the F4i is the fuel injection system. I might as well come clean right now and say that have not been a big fan of fuel injection. While it seems like Japan's gift to internal combustion to some, most of them seem just a little too touchy to me. I also don't care for all of the electronics it takes to make the thing work, but I have to admit that this system is undeniably the best one I have sampled. It works superbly. I can best sum up my impressions by repeating a conversation I had with one of my colleagues at the intro. This guy is a serious racer and competes at the front of the pack in his class in the AFM. During dinner, after riding the F4i all day, I asked him how he liked the injection system. He looked at me and said, "Oh, yeah. It's injected isn't it?'

That pretty much sums up how well it works.

The fuel injection system operates at 50psi and each cylinder gets a single injector with four nozzles. The bike needs no choke lever because its done automatically. 

Because of the fuel injection and the catalytic converter on the California models this bike meets CARB 2004 Tier 1 emission standards and only loses two horsepower to the 49 state model. The injection system has a diagnostic feature much like the VFR800. When you put down the sidestand and short out the service connector under the seat, an LCD on the dash flashes a code that pinpoints the problem.

A bike that "carburets" well is easy to holeshot and I was very surprised at how hard the CBR929 would leave from a dead stop. With this in mind I did a little impromptu holeshoting of my own with the F4i and the injected model is definitely easier to launch than the carbureted model. I may become a disciple of fuel injection yet.

The bike will come with three different tires: Bridgestones, Dunlops and Michelins. The purchaser will have no choice of tires. You get whatever your bike comes with.

The bike I rode on Thursday came with Michelin Pilots and these tires are excellent. I sampled them at the CBR929 intro. and was very impressed then. They the equal of the Dunlop D207GPs I normally put on my personal race bike in feel and grip. My only reservation is that they definitely warm up a little slower than 207s, but once up to temp, they are very good indeed.

During the first session on the track the F4i was not my friend. I was running over cones and missing apexes like drunken sailor. The F4 is not an easy bike to ride. Like a surgeon's scalpel, if you are careless, you can do a lot of damage. And then there was a problem with the brakes. By the end of the first session, the front brake lever was mushy and coming very close to the handlebar.

Luckily, I survived the first session and during the second outing I started to come to grips with this bike. For one thing, the bike is so light that your body placement is essential to a fast lap. Once I learned to scoot back on the seat, the rear tire quit squirming on the exit of fast corners. When I quit hanging on the bars, the front end stopped wagging. When I got my eyes up and started to look through a corner, the bike started to go where I needed it to go.

During the lunch break the bikes got new tires and brake pads. By the third session I was ready to get out my checkbook. Steering was precise and razor sharp. It changed direction effortlessly, but even at 150mph it was rock solid. It went exactly where I pointed it. The engine was also strong. I saw an indicated 156mph on the speedometer before braking for turn one at Las Vegas Motor Speedway. And I was very surprised that I was able to take a quick look at the digital speedometer on the F4i and check my speed before braking, as on the F4 I was hard pressed to read the analog speedometer at its indicated 150 mph.

And the brakes were back. Honda's hard working crew of engineers gave me back a bike with wonderful brakes after they changed the pads and bled the system. According to Doug Toland, the bikes were run pretty hard for two days before the press arrived to work out the proper suspension settings. This testing took its toll on the brake pads. Toland went on to say that they found 20mm of race sag to be ideal which is quite a bit less than I would have expected.

Just before I went out for the fourth and last session on the bike, an instructor for Freddie Spencer's racing school, where we were based, came up to me and suggested I not lock my elbows when braking. I was getting some mild front wheel hop under hard braking and was ready to try more rebound in the front forks to cure it, but after taking his advice the hopping went away.

After riding the F4i most of the day I rode the 2000 F4 that Honda had supplied for comparison. There is no doubt that the F4 is a fine motorcycle. In fact, I was surprised at just how good it was, but the F4i had it beat in power, shifting and handling. The F4i felt much faster on top, due in no small part to the shorter gearing. The handling was noticeably slower on the F4 when negotiating the chicane at the end of turn one but the difference was not nearly as large as that between the CBR900 and 929.

After spending a day thinking about the two bikes I have decided that in order for the CBR600F4i to be a better track bike it will have to compromise some of its street prowess. Things like lugs for a steering damper, higher foot pegs (the F4i's drag pretty badly on the track) lower handlebars and the ability to easily reverse the shift pattern are not found on the F4i, but then you hardly need those things on a street bike. Getting more power means shifting the torque peak up closer to red line which is fine on a race bike, but not as desirable on the street where you need low rpm power more often than not. And you must consider the skill level required to ride the F4 and the latest crop of sporting 600s.

Yes, the F4 is at a crossroad and time will tell which road Honda will take in subsequent iterations of this model. I asked Takeo Yokoyama, the engineer responsible of chassis design of the F4i if Honda was working on a CBR600RR. 

He looked at me and said, "Honda have many engineers working on many projects."
Ends

Related: Honda web site features the grand-pappy of the F1, the Hurricane

Mike Ross is an instructor at the Motorcycle Mechanics Institute, and has been testing streetbikes and club racing for more than ten years. He lives in Arizona.