Honda CBR600F4, It's Got Stuff

If you're lazy and don't want to bother reading another full test of the Honda CBR600F4, and if you want to torture the publisher of 2wf by not looking at any of the other very fine pages we've put together about this bike, then here it is in one sentence: the F4 is just as remarkably good in today's world as the F2 was in it's day eight years ago. Street or race, sportriding or commuting, the CBR600F4 does it all.

Ut oh. I think I pissed off the boss. Quick, save my ass and download all of the F4 pages.

The CBR600F4 Stuff What's the big news? Well, as you know by now there's much new about the CBR600F4 from minor tweaking of the F3 design to major redesigns, construction, and material. Here are some things you might not have heard about the bike's parts.

The Honda CBR600F4 engine isn't, as you know, just lighter and more powerful, it's also going to prove to be more reliable -- if that's possible. The tricks that Honda performed on the engine to boost its power include details of redesign that were both achieved and dictated by the latest high-tech materials available. In other words, Honda could not have sold you this bike ten years ago because at that time the existing materials couldn't have fulfilled the needs of this design. If a 600cc bike at that time had this kind of power and rpm range, it would have been much heavier and very, very expensive. Honda has long been the king of high revving inline engines but the screamers that they built in the past were kept on short leashes.

For some reason 13,500rpms just seems natural.

To help achieve the high-revs that the F4 is capable of, Honda redesigned the engine's capacity by making it an over-square design of 42.5mm stroke and 67mm bore. This allowed Honda to reduce the piston speed so that even though the engine revs higher, the piston speeds have only increased a small amount. Relatively speaking, that is. The piston-to-bore friction was also reduced by using the same technology that Honda applied to the new VFR800 Interceptor: LUB-coat coating on the piston skirts and impregnated, sintered aluminum sleeves for the bore. No, you cannot overbore the engine.

On the intake side of the engine, the F4 now has a for-real ram-air system that features weird looking polyps just inside of each ram-air opening. Other bikes have these things also, such as the Kawasaki ZX6-R and if you've been wondering why they're there, it's to help reduce the chances of improper mixture when a rider goes full-on throttle at low speeds.Without the bike moving forward to create pressure inside the airbox, a hard twist of the

throttle at low speeds can momentarily use up all of the air within the box. The intake sacs provide a greater volume of air within the bike to keep the engine from over-richening under those conditions. They're sort of like having a third lung.

Honda's F4 ram-air is a two-stage system that also provides pressure to the float bowls and CV diaphragms. The bike has little ram-air injectors located at the front of the fairing that are used for low speed, but at high speeds they are closed off and the bowls and slides are then pressurized from intakes housed within the airbox itself. The reason for this is because if the outer openings were used at high speeds the bike would become fuel injected and the faster a rider went the more injected the bike would become. But the idea behind the F4 having ram-air to the floats and diaphragms is to ensure that fuel can flow and that the slides can lift; it's not meant to blast the gas out of the float bowls and slam the slides open. For increased flow, the intake tract angle was changed to a steep 40 degrees. This was achieved in a very cool way that will probably set the trend for other sportbikes to come. The top of the F4's head is not parallel to the bottom, but has instead been canted forward to allow for the straightening of the intake tracks. This should prove confusing to a few local machinists when guys try to get a few tenths shaved off the bottom of their heads.

Honda has followed Suzuki's lead and gave the F4 four transistorized direct-ignition coils integrated into each sparkplug cap. Believe it or not, this actually reduces the bike's weight by 13.5 ounces. The rest of the engine package is your general lighter, smaller, better power plant. So what else is new?

The F4 uses swingarm plates and the engine cases for the swingarm pivot.	The F4's chassis is radical for the F series by virtue of it now being constructed out of aluminum. It is, of course, both lighter and stronger, as we've come to expect from every performance bike. Where the frame departs from all other designs is how it has swingarm plates even though the extruded aluminum swingarm's pivot is essentially located in the rear of the engine cases. It's a new twist on that tuned flex thing, if you'll forgive my pun. Honda's VTR1000F doesn't have swingarm plates on the frame and the F4 is sort of a combination of that design and a conventional design of swingarm plates only. It's clear, though, that the significant swingarm load is borne by the engine because there is no bracing between the swingarm plates from one side of the bike to the other. Until they're bolted fast to the power plant, anyway. The CBR600F4's forks are still of conventional design like those of most of its class competition, but the diameter of the tubes has been increased to 43mm from the F3's 41mm. This is because all of that stuff you used to read a few years back about how conventional forks were a bad design because of how they flex has turned out to be quite wrong. Yes, they do flex, but flexing forks are actually a good thing and any pro racer can tell you how the F series Hondas have always excelled in how their forks give riders excellent feedback as they bend and flex and go squirmy under hard braking. The new forks of the F4 are completely adjustable and the range of damping provided is all any street rider will ever need. Should ever need.
Conventional forks of 43mm do the work up front. Honda sticks with four piston calipers for braking. And why not?

The F4 will make you feel like you can fly. Or at least make you feel like dropping clams on rocks is a good idea.

Riding Impression
The first day that we took the CBR600F4 out for a ride and a few pictures, we rode only as far as the Pacific Coast Highway in Santa Monica before the threat of rain cut our journey short. It does rain in California. The following day we were successful, but it was very cold. Like in the 40s. This time we jaunted up into the San Gabriel Mountains, but photographer Blake Conner took his girlfriend's sporty, performance car rather than a second test bike or his clapped out CBR900RR that he usually rides. Blake thought it would be cool fun to try to race up Sand Canyon for a bit of a car/bike comparison. [Disclaimer: We use the word "race" in its broadest sense and do not mean to imply that we would ever exceed the legal speed limit on any public highway. Racing is for the racetrack only. This test report is not a confession and I have not sworn on a stack of bibles so it is inadmissible as evidence in court.] Blake whipped the piss out of that poor little car so don't tell his girlfriend; she'd be a bit miffed. She did wonder why her gas tank was half-empty after lending Blake the thing for only a short afternoon drive. I mean she lent him the car, not the gas tank.

Anyway, now that you've got something you can't tell Blake's girlfriend, here's something you can't tell Blake. I was sandbagging on the F4. After the shoot Blake told all of his friends that I'm a big baby and that I couldn't even outrun a car while riding a bike on a twisty road. What a big mouth liar. I had to slow down repeatedly to let him catch up so that I could have the joy of entering each corner with the sound of squealing car tires behind me.

That did cause a bit of trepidation on my part but it was just too silly to resist seeing Blake slide half out of control through every turn while I casually rode along watching him in my mirrors almost as much as watching the road in front of me. We don't recommend trying this with your bike and a friend driving his girlfriend's car. Remember, we are paid professionals. Sure it's simply by tautological reasoning that we are professionals because of the fact that we are paid but, so what, it works for us.

Again, anyway, what we were seriously and most interestingly reminded of by this foolish experiment was how sadly performance-challenged cars are. After a short blast down a twisty road of barely 15 miles the F4 was as good to go afterwards as it was before we started. Like you, we expected nothing less. But the car -- this sporty car with its sport suspension and performance parts -- was all used up barely halfway through the canyon. Its brakes turned to marshmallows, its suspension turned to Jell-O, and the steering turned to caramel. Yes, the car virtually melted into gooey, sweet dessert foods. For the last half of the trip I couldn't go slow enough on the F4 to keep the car in sight. This makes one wonder just how much money you'd have to spend just to get a car that performed simply adequately.

We were shooting the pictures of the CBR600F4 on just our first day of riding the bike outside the city and although it was cold I was still stunned when the rear end came around on me while making passes in front of Blake and his camera. This happened after a number of passes so the tires should have been warm and sticky. Or so I thought. I stopped and we inspected the bike and discovered that the tires were still cold. So we decided to do the right thing and check the air pressure. 44lbs.!! This got me wondering whether or not the guys at Honda aren't trying to see if I'm really doing my job. Or am I just being paranoid? One thing for sure is that this taught me that the Dunlop 207 street tires that the F4 comes with work much better at the recommended pressures. After dropping the pressure about 25% the tires warmed up and stuck to the pavement much better, thank you.

Middleweight bikes have long tended to be peaky because that's historically been the only way to get the most power out of them. Horsepower is found primarily in the high revs so the cams and pipe and all have usually been designed in a sort of compromise to maximize the power where it lives. But the thing that stands out about the F4 is that there's basically no peaky rush of power up top. The little thing just pulls like a baby train from midrange all the way up to its way-out rev limit. This is also astounding because ram-air generally makes a bike even peakier because it gets jammed full of the good stuff at high speeds. Yet the F4 just storms up through the gears almost like a big-bore bike.

Simply put, the CBR600F4 just makes riding too damn easy and once again Honda has created a 600cc machine that really can be everything to everyone, possibly even more so than Honda's own VFR800 Interceptor. Like the F2, the stunning thing about the F4 isn't that it is going to win many races for both privateers and the factory guys, it's that it is a wonderfully balanced machine for any kind of street riding and it is going to win those races. The F4 is a blade on any twisty road,it is light and easy to

ride in city traffic, and it has two-up comfort -- maybe not quite as comfortable as the F2 or 3 but nonetheless, the passenger's knees are below the passenger's head which is unusual for a sportbike. And on the droning highways of America, the F4 runs in pace without effort like a bike with twice its engine size. At 70mph the F4 is at about 6,000rpms but there's absolutely no buzzing in the bars or pegs. If it weren't for the tachometer you'd swear the bike was loping along at 3 grand.

Machines like the CBR600F4 make my head spin trying to figure out how bike manufactures can make an honest dollar. There is a car in every garage but there certainly isn't a bike in every one and so it's mentally debilitating trying to fathom how so many motorcycle

manufacturerscan spend so much in development, marketing, racing, advertising, press introductions, more development, and so on, yet still actually show a profit in the end. We yell for more, better, faster, lighter, and we get it.I can chew gum and run but I can't imagine even for a moment how motorcycle manufacturers can make money without my knees getting weak and me toppling over. Oh, I almost forgot. The CBR600F4 we tested topped out at 158.3mph at our high-desert, top-speed testing facility. An aftermarket pipe will get it over 160mph. No wonder the midleweight class bikes are the best selling in the States. The CBR600F4 is all yours for $7,899. That's less than $0.58 a rev.