Honda Vfr750f
HONDA VFR750F
CYCLE WORLD TEST
LIGHTNING DOES STRIKE TWICE
CLICK. Fifth gear, front straight. Engine speed climbs as Turn One grows larger in the distance. The first marker blurs past. Glance down-135 mph on the speedo-then hard on the brakes. Click.
Fourth. A hard dive into Turn One, the needle nudging 100 mph, then back on the gas. The rear tire nibbles at the edge of traction, then catches as the turn opens up. Keep turning left, setting up for the next turn. Down the short straight, a tap on the brakes, and roll right into long, fast, sweeping Turn Two. The horizon tilts crazily, the asphalt on the right so close that it fills periph eral vision.
A typical part of a typical lap at Willow Springs Raceway. Except that on this day on this bike, it all seems too easy. Not because of any exceptional rider skill; rather, the ease. comes from the motorcycle, Honda's new VFR75OF Interceptor.
Of course, any replacement for the original 750 Interceptor would be ex pected to handle the racetrack with ease. That landmark sportbike set new standards for style and perfor mance back in 1983, standards that led directly to today's 100-horse power 750s-the very machinery, ironically, that made this new Inter ceptor necessary. And in practically every way, the VFR lives up to those expectations. On the racetrack, in the backroad twisties, even when cruising city streets, the VFR either runs right with its competition, or runs away from it. So should they be pleased about the VFR’s relatively light weight. At 474 pounds (without gas), it bests the old Interceptor by 41 pounds, and is 17 pounds lighter than a Yamaha FZ750. The GSX-R750 is still the class featherweight at 423 pounds, but at least this latest Interceptor no longer spots the Suzuki the weight of a passenger. And the weight loss did not all come just from the aluminum frame; it came from everywhere, from a rear wheel more than two pounds lighter, to a lighter front fork where the 37mm stanchion tubes are 2mm smaller than their predecessors, and where reduced wheel travel has netted a shorter (read: lighter) fork. But if the VFR’s feel can’t dispel that old-interceptor déjà vu, its exhaust note can. The 180-degree crank has lent a racier flair to the exhaust, which was so flat and droning on the old VF it was often described as having all the excitement of a lawnmower. But the engine now has a low, soulful moan, especially at lower rpm, which gives it a wonderful sound not unlike that of a Yamaha V Max. That moan turns into an out right wail as the VFR reaches its 1 1,500-rpm redline, but you usually can't hear the engine at higher speeds, due to the government's new 80-decibel noise limit.
The way in which Honda achieved that result is almost as interesting as the bike itself. Generally, the designers of new Japanese motorcycles follow one of two patterns: They either start with a clean sheet of paper, throwing away everything old and embracing new concepts and configurations; or they heavily base the new bike on the parts and tooling from a previous model, ending up with basically the same machine, but one that is improved and endowed with the latest features. Both approaches have their pros and cons. With an all-new design, the errors of the past can be corrected, although the problems of the future can be created in the process. Working with an existing design may be safer and more cost-effective, but it restricts performance potential.
With the VFR750F, Honda’s designers have attempted to capitalize on the positive aspects of both approaches while avoiding the negative ones. They preserved the essence of the original 750 Interceptor within the new VFR, and yet, only the most basic details were left unchanged: the 70mm-by-48.6mm bore and stroke,
the 90-degree, liquid-cooled V-Four engine configuration, the Pro-Link single-shock rear-suspension concept, and a familial styling resemblance. Everything else was subject to change—and to lessons learned during three years of producing and racing Interceptors.
And make no mistake: Honda’s racing fraternity had a lot to say about the VFR’s engine. All over the world, 750cc racing formulas based on production engines had emerged, and Honda and its distributors wanted an engine that could be competitive in American Superbike, European endurance and English FI classes. The people responsible for turning street-going Interceptors into racebikes wanted a new engine that would be compact, reliable, and have outstanding power potential.
Fortunately for Honda, what the racers wanted meshed well with what was wanted by the product planners, the people who tailor new motorcycle concepts to fit the market. The planners needed a machine that could equal or surpass the achievements of Yamaha’s FZ750 and Suzuki’s GSX-R750—meaning that the VFR would have to produce more than 100 horsepower, have an excellent powerband, and be stoneaxe reliable. In other words, they wanted a 750 whose performance would write its own ads.
This coincidence of needs gave the engineers a free hand. They refined and improved the parts of the concept they decided to keep, incorporating features that had been tested in racing versions of the previous VF engine, such as the gear drive to the dual overhead cams (also used in the VF1000R streetbike) that reside atop each cylinder bank. They straightened the intake tracts, provided each cam lobe with its own individual jet of lubricating oil, and designed new valve gear that uses an individual rocker arm for each valve rather than having one forked arm open two valves. Those refinements allegedly eliminate the cam-wear problems of the VF750, while also permitting higher engine speeds.
Also of significance is the VFR’s 180-degree crankshaft, which replaces the 360-degree crank used in the previous engine. This configuration not only results in a more-even firing order, but it allows the exhaust system to be designed for better scavenging, thus boosting power output.
And more power it has, indeed. With a claimed 104 horsepower compared with the VF’s 86, the VFR produces fully 20 percent more power. But the engine speed required to accomplish this feat has increased only five percent, from 10,000 to 10,500 rpm. So even though the VFR has an 1 1,500-rpm redline, this isn’t an engine that has power wrung out of it through outrageous engine speeds; this is an engine wherein every hidden horsepower has been coaxed out of hiding by experts, an engine where efficiency and refinement have been put before hot-rodding techniques.
Like the engine, the VFR’s chassis was shaped by the needs of both the market and the racing team. The market demanded light weight and aluminum tubing; the racing team insisted it be strong enough, once slicks were mounted and 30 horsepower added, to satisfy the likes of Wayne Rainey and Freddie Spencer. The twin-spar aluminum frame bears a passing resemblance to those used on Honda’s 1985 endurance racers, but it really is its own design, simplified for the exigencies of mass production. The large main tubes are extruded, as are a few others; the steering head and most other parts are cast. The real news is that this frame, with the engine bolted in place, is claimed to be 50 percent stiffer in torsion than the VF’s steel frame. That should make the racers happy.
While some parts were shrinking during the diet, the VFR’s full fairing was growing. The designers tried to give more rider protection while improving aerodynamics, paying particular attention to airflow while the rider is in a normal sit-up position. But Honda claims the VFR has less drag than any of the competing 750s, no matter if the rider is sitting up or in a full racing tuck. That’s hard to prove, although the VFR’s astonishing 150-mph top speed shows that its power and aerodynamics can produce some impressive numbers.
Despite all this change, however, Honda’s newest high-tech marvel still feels like an Interceptor—not, however, like the previous 750 Interceptor. It instead feels more like a
500 Interceptor, albeit one with 50 pounds of additional weight bolted to its frame and 40 more horsepower stuffed into its engine. Obviously, then, the VFR feels smaller at first than most recent 750s; the footpegs seem slightly higher than those of its predecessor, and the handlebars are a touch lower. But overall, the riding position is standard sportbike-compromise, with just enough forward
lean and rearward foot positioning to provide a good high-speed posture without ruining the motorcycle for everyday use.
That socially responsible exhaust note has not come at the expense of performance, though. There's usable power on tap at the very bottom of the rev range, and it builds smoothly all the way up to around 9000 rpm. From there to redline, there's a no ticeable surge in power; and within that 2500-rpm-wide range, the VFR is a very fast 750, one whose perfor mance is only a notch below that of much larger bikes.
It's fast at lower rpm, as well, but the unusual smoothness of its power delivery belies that fact. By compari son, the FZ750 Yamaha responds al most explosively when the throttle is rolled open, whereas the VFR just motors away so effortlessly that the engine doesn't seem to be working all that hard. But in the end, the VFR is the equal of the FZ750 in roll-on acceleration, if not its better. --
What's more, the VFR handles as effortlessly as it accelerates, with that much-sought-after combination of quickness and stability that puts a rider at ease. By current, 16-inchfront-wheel standards, the steering is slightly heavy at high speeds, but the bike still responds immediately if given the right input. It also feels as if it responds only to its pilot, with no intentions of its own concealed any where in its solid chassis. The steer ing is more linear than the previous Interceptor's under all conditions, with much less tendency for the front wheel to tuck under or the bike to sit up while braking into a corner. For this, you can thank the VFR's nar rower front tire (a 11 0/90V 16 vs. a 120/80-16 on the old VF), along with its increased front-wheel trail (108mm vs. 96mm), its lower center of gravity and its lighter weight.
On the racetraci~, the VF~R's han dling and smooth power allow any rider to look his best; it's simply an easy motorcycle to ride quickly. But whether that will translate into pro duction-racing wins is another mat ter; Suzuki's GSX-R, with its 50pound weight advantage and its abundant ground clearance, is a for midable foe. Furthermore, the VFR drags its exhaust pipes on the track, even with the stock tires. Raising the rear of the chassis by turning up the VFR's hydraulically actuated rear spring preload improves cornering clearance; but it also allows the spring to overpower the rebound damping of the non-damping-adjust able rear shock and cause a slight loss of traction over small bumps.
Each valve is actuated by its own rocker arm. Putting the valve-lash adjuster at the pivot end of the rocker reduces reciprocating weight in the valve train.
That isn't a problem on the street, where you'd have to be a bit of a loon to lean a VFR far enough to touch metal to the ground. Because as de lightful as the VFR is on the track, it's even better on the street. The suspen sion is firm yet compliant, and keeps the wheels well under control with out a punishing ride-though on a choppy road it's no Gold Wing. The engine is almost vibrationless, de spite being a stressed chassis mem ber. The seat and seating position are an excellent compromise between everyday practicality and super-seri ous sportbiking, allowing a rider to burn a full tank of gas or more with out feeling any real discomfort.
Still, it~ oiily when you ride this motorcycle hard-really ride it and press your limits-that you begin to appreciate just how wonderfully it works. The engine and the chassis both respond in such a linear and re assuring fashion that practically any one who gets on the bike rides more smoothly and confidently than he would on any other 750.
That's high praise, considering the depth and ability of the current crop of 750cc sportbikes. But it almost seems as though Honda is sending a message with the VFR, telling the world, "If you thought our first at tempt at building the Interceptor was something, wait until you see what we can do on the second." We have, and we like it.
HONDA VFR750F
