Even stood still, the CB900F looks to be going some. The lines are cleverly swept back with bodywork and decals matching the angles of the pipes, and other metalwork complementing each other superbly. The overall styling, indeed many of the mechanical features, echo those found on the six-cylinder CBX while the beefy looking four cylinder engine sits high in the frame to help out in the ground clearance department.
In use the CB is without doubt a big machine, with an all up weight of 233kgs and a lengthy wheelbase too, but it carries its weight and bulk well, the rider sits deep in the plush seat with the tank up in front of their chest. The big wide bars end just where your arms do and give a great command over the bikes progress while the seating and footrest position are also bang on for both comfort and control.
The DOHC engine is tuned for a stonking midrange with shoulder tugging acceleration from around 4000rpm all the way to it’s redline just a shade short of 9500rpm. There is some considerable vibration as the engine passes through the midrange, a bi product of the long-stroke motor, and something that was addressed with the F-C model when the rear of the engine was rubber mounted and a set of swing tie rods allowed the front of the engine to move and dampen out the impact upon the chassis. On the earlier machine, the vibes add to the urgency of the ride and definitely add a hint of excitement to what really is a much steadier ride than first impressions create. From low down in the rev range, around 2000rpm in top gear, the engine is responsive and willing to go, carburating smoothly and cleanly all the way to its redline of 9500rpm. There is a definite drop in power around 8500rpm however and the engine doesn’t increase its output once above this figure despite revving quite freely to get there so little except heavy fuel consumption is to be had by taking the needle to that part of the dial. Maximum torque is had around 7500rpm so the best performance and fun is to be had by sticking around those two figures. At speed the CB900 demonstrates itself to be the very best handling Honda thus made, leaving the old single over camshaft CB750 dead in its tracks. The combination of the big engine, wrapped up in what is effectively the 750 chassis, is devastatingly good.
For the period, the CB900, with 95bhp and fine handling on tap, could be viewed as an almost perfect machine. Where others wallowed, the Honda tracked true, when the bigger bikes pushed the brakes to the limit the CB simply stopped. It really is like chalk and cheese when comparing the bikes of 1979 alongside each other, with the Honda having been through finishing school while the rest bunked off and had their manners left unkempt. mid corner when opening the taps on the Suzuki or Kawasaki has the rear end shouting with complaint, the grunty Honda just lays the power down seemingly without over-stressing the rear tyre. On the brakes too the font end of the Honda is still working well while others refuse to help out with the steering or change direction easily. At low speed the CB does feel to drop in too easily, this is most likely attributable to the type of front tyre fitted rather than a design fault and is quite helpful as, if the weight of the bike is ever noticeable, it is at very low speed and without the power of the engine on hand to assist. The advantage enjoyed by the Honda was a short lived experience however, as by 1981 Kawasaki had stolen the march on handling with the GPz series, this revolve of gain over gain with the lead in performance, no matter how minor, changing hands, continues unabated today.
The only real tangible fault I could find with the CB has to be the rear brake, the disc is too large, diameter wise, and at times can overpower the wheel. This could be a fraction of the size, as indeed could the huge lever used to operate it, and still be very useful at hauling the bike up but without any fear of locking.
The real star of the CB show is hard to define; it could well be the engine with its wide range of torquey, usable power. After all the power plant did find its way into many a special like Bimota HB2 and Harris Magnums. But that would be grossly unfair to the chassis that is both stiff and sweet handling. The high specification Showa suspension also deserves much credit, for a straight out of the showroom machine the CB900 was a revelation for its time, before then, the pogo’ing and wallowing was accepted as the norm until you up rated with Marzocchis or the like. Now you could buy a machine that didn’t need such work and Japanese suspension, both thinking and engineering techniques, had finally come of age. To sum up, the CB cannot be broken apart and one area pointed at as being the jewel in the crown, it all works as a whole straight out of the crate.
Model History
Honda certainly took their time coming up with a worthy replacement for the single overhead cam CB750 engine. You could almost say that, while able to be at the very forefront of engineering and technology, Honda was, in reality, very slow to react to the demands of the market place. This was a trait that cost them dearly thought the 70’s and 80’s as they tried to force unwanted technology like turbos and complex, and untested, V-4 engines, upon the market place. While the Japanese opposition launched model after model, in an endless stream, equipped with double over head cams and other such modernity’s, the original single cam CB range soldiered on almost to the point of embarrassment. This was a strange set of circumstances as Honda had already pioneered such designs in their race machines of the 60’s and yet seemed reluctant to bring this thinking to the street. To add to this, the other three Japanese factories where out there, chasing GP glory with a bevy of brutal 500cc two strokes, while Honda stayed at home.
They did however enjoy considerable success in the heat of European endurance racing and it was the machines used for this sport, the advanced 24-hour racing RCB fours that gave much of the inspiration behind the CB project of 1979. Using a similar engine design to the CBX1000, the new 750 and 900cc bikes, the European only F series, marked a change of direction for the mighty H and at last they were taking on the rest in the sports bike stakes. Although the CB900F engine differed in many ways from the endurance racer, the basic layout was immediately identifiable with a chain primary drive replacing the gear drive of the old CB750 and, of course, the distinctive twin cam shaft layout that makes the top end of the engine unmistakably Honda. The main changes a necessity of transforming a prototype racer into a viable road going machine, looking around the RCB race machine shows the hand built nature of the beast with most modifications being a result of in the field tests and not the produce of a proper development cycle expected of an end user machine.
The CB900F retained its silhouette and general looks throughout its five-year life but many detail changes were made, most in the interest of improvements to the stopping and handling. Two years into the life of the CB, the brakes were uprated with twin piston calipers, while the forks were beefed up too, the later versions now measuring, a whopping for the time at least, 37mm. In March 1981, the first of the faired version the CB900F2-B was introduced and met with much enthusiasm I the UK and Europe. It was this model that formed the basis of the CB100R arguably the most desirable of all the 80’s Honda until the RC30 hit the dealers.
Other changes included a stronger cam chain tensioner, this was a most welcome addition as the earlier models could become rattley in the top end when the tensioner gave way. For the 1981 B series the was also the appearance of the F2’s, the F2-B having the three quarter fairing following the same styling as the CB1100R race machine. This transformed the looks of the 900 making it look more streamlined and speedy too. For the following year both the FC and F2-C grew a few more millimetres of girth around the fork stanchions, this time measuring 39mm and, with the addition of the Honda TRAC anti dive system grew more and more like the bigger racing brother.
When the CB900F eventually hit the showrooms stateside it made more of an impression than it ever did in Europe, despite the design having been crafted especially for the European market place. This was due to the startling ride to the fore of a certain 19-year-old, Freddie Spencer who, on a race equipped CB with a light switch power delivery and in excess of 130 horses, really set the world alight. From a distance this machine, along with the others in the US Superbike class, looked like the road bikes they were meant to represent and freely available in the showrooms but close inspection revealed otherwise. The American market also received the CB900C version, a custom styled machine using different cams to smooth the power even more.
Honda CB900F timeline
1979 CB900 F-Z – chassis number SC01-2000042
The first of the CB900’s to hit Europe, this all-new Honda was designed specifically with the UK and European markets in mind, one of the very first Japanese machine to be conceived this way, previous to this the US played a large part in all development
1980 CB900 F-A – chassis number SC01-20100001
The A can be distinguished from the earlier Z by the modified forks that have linked air caps on top of each leg. The Comstar wheels were also reversed so they look similar but are in fact inside out.
1981 CB900 F-B – chassis number SC01-22000028
The single piston front brake callipers are replaced with slightly more powerful twin pot items while a vacuum type replaces the fuel tap. Small changes within the gearbox enable a smoother shifting while the discs also get a redesign to help reduce vibration, the type was also introduced into the US with great success.
1981 CB900 F2-B – chassis number SC01-4000342
This is the faired version of the standard B model, the fairing features a new design of headlight, a quartz clock and also a voltmeter
1982 CB900 F-C – chassis number SC09-2000017
The C model saw a few changes, a revised front master cylinder and calliper brackets along with a new engine mount designed to damp out the mid range vibration. Anti dive forks are implemented for the first time too while at the rear remote unit dampers handle the bouncy bit. A balance pipe now joins both silencers.
1982 CB900 F2-C – chassis number SC09-4000424
1983 CB900 F-D – chassis number SC09-4100001
Cosmetic changes the D model apart was no different to the previous version
1984 CB900 F2-D – chassis number SC09-4100811
The faired version of the D
Honda CB900F-Z Specifications
- Engine – four-cylinder four-stroke transverse 16 valve DOHC
- Capacity – 901.8cc
- Bore & stroke – 64.5 x 69mm
- Compression Ratio – 8.8:1
- Carburetion – 32mm Keihin CV
- Max Power – 95 bhp @ 8500rpm
- Torque – 43.6 ft-lbs @ 7500 rpm
- Ignition – transistorised
- Transmission – 5-speed chain final drive
- Frame – steel tube twin cradle
- Suspension – 35mm telescopic forks air assisted damping. Twin shock rear adjustable pre load,
- Wheels – 3.50 x 19, 4.25 x 18
- Brakes – 276 mm discs single-piston floating-caliper. 295mm disc single-piston floating-caliper
- Wheelbase – 1515mm
- Weight – 233kgs
- Fuel capacity – 20 litres (inc 2 ltrs reserve)
- Top speed – 132 mph
Honda CB900F Gallery
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