Honda CB 900F-B Bol D'or

Honda DOHC History

After years of technical and commercial hegemony Four models, Honda, to meet competition from other motorcycle manufacturers, it ceases production of the series CB shaft and at the end of 1978 presents the new exhibition in Cologne, CB750K, which will be the parent a series of new models with four-cylinder engine with double overhead camshaft.

The CB750K is characterized by rather soft lines that add to the four separate pots, raised the handlebars and the rear drum brake, suggest a movement of more tourist and recreational setting and seems to mark a return to the past than the last model SOHC . This first impression is contradicted by the 4-cylinder engine of 748 cc, which delivers a maximum power of 68 bhp at 9000 rpm at the wheel with all relevant performance: maximum speed 196 km / h, 0-400 meters from standstill in 12.57 seconds. It also presents several new techniques such as four valves per cylinder and double overhead camshaft distribution in the head with pads and shorts instead of the classic rocker. The four valves per cylinder and measures of square bore and stroke prone to make the engine run up and take it easy laps. The CB750K finally turns out to a good compromise between tourism and sport.

The following year, also to address the high cost of running the six-cylinder model, Honda decided to build a four-cylinder sport markedly more inclination. In early 1979 he was presented the first CB900F-Z, who proudly carries the inscription on the side panels Bol d'Or to remember the noble, but only virtual descent from the competition model. The look of the bike has a sportier impression of CB750K: tank, side panels and tail well harmonized and slender make modern and pleasant. The four-cylinder engine and four-valve maintains the same architecture as the 750 cc. The increase in displacement was achieved by increasing the stroke to 69 mm to 64.5 mm el'alesaggio for a total of 901.8 cc. So we have a long-stroke engine, even a distribution, which is more elastic CBX1000 the same six-cylinder. This choice is determined primarily by the need to minimize the footprint of the transverse engine, the bore is also the same as the CBX, and this allows you to take all the experiences of fluid head made for the 6-cylinder models. The maximum power is increased to 80 hp at the wheel at 9000 rpm. Resumption and acceleration of all show respect for the Honda at the top in the production of high-performance 4-cylinder. The 400 meters from a standing start are crossed in 11.75 seconds and a top speed of 213 km / h.

In 1980 it was marketed version CB900F-A, which differs from the model Z only in some particular aesthetic: Chrome Frames are eliminated by the arrows, the rims are not more blacks and silver and the writing on the side panels CB900F is raised.

Also in 1980, while still in production, K, is a new version, the CB750F-A. Compared to the K version of the main innovations are in the brake system, now fitted with three disk brakes, and increasing power of a horse through the adoption of a 4 into 2 exhaust. Some changes to the chassis also makes the bike easier to handle. The aesthetic is very similar to the model 900 and is distinguished by a dumbbell fly a bit 'higher, a different instrument panel and the lack of oil cooler.

In 1981, alongside the classic CB900F is marketed the CB900F2-B. The latter has a full fairing large. It also mounted a more robust fork with the fork 37 mm, the brake system is equipped with dual-piston calipers and discs have a different design. Small changes will have to aesthetics, the rims are gold and the inscription on the side panels is no longer relevant.

The CB750F has remained the same the year before, in 1982, is joined by model faired CB750F2-C and the latter are taken on dual-piston calipers.

In the same year in the two models CB900F CB900F2-C-C and substantial changes are introduced to the chassis, the rear shock absorbers have separate tank, brought to 39 mm forks with jumper struts, anti-dive Trac device. Also replaced the wheels that are now the most modern Comstar Boomerang with small front, 18 "against 19" of previous models.

In 1983, the development of the two models is stopped, the news is very marginal and 900 cc models present only minor aesthetic changes that mainly concern the colors. That same year, however, marketed a new model: the CB1100F called Super Bol d'Or, which will remain in production only one year. The increase in displacement is obtained by increasing the bore by passing the 64.5 mm to 70 mm 900 cc engine, however, remains unchanged at 69 mm travel. The engine thus has a total displacement of 1062 cc and an output of 94 hp at the wheel at 8500 rpm and is equipped with high torque at low and medium rpm. The bike has performance of all relief, accelerations (0-400 meters from standstill in 11.48 seconds) and very close to top speed 220 km / h, which, along with great handling and lack of vibration makes the drive very pleasant .

CB750C CB750F is a custom version of the. Produced from 1980 to 1982 did not have big market in Italy. Although the engine is the same as the maximum speed is 750 to 176 km / h, the weight is increased by ten pounds and the tires are wider. This model also has fenders and other details such as the covers of 'airbox and chrome chain cover.

Along with these models from 1981 to 1983, Honda also developed a motorcycle racing suits, the CB1100R. The motion (in three versions B, C and D) is produced in about 4000 copies and comes from the CB900F, the architecture of the chassis and engine are very similar and also the fairing, especially in the first version, reminiscent of CB900F2.

The engine has the same race and the same boring CB1100F, but the pistons are forged camshafts are modified with "geometry" kick start "the primary chain and the larger more modern gear. The exhaust system has the same size and shape to the 900, but collectors do not have a double room and then their inner diameter is greater.

The major innovations were introduced in version C which has the carbon fiber casing and the aluminum tank, a fork, equipped with antidive, larger vented front brakes and wheels Comstar Boomerang.