BMW K1

The BMW Kl was the solution to a serious problem that faced Europe's largest motorcycle manufacturer in the late 1980s. Although well-established the product line-up was looking increasingly tired and dated. Their range of K100, K75 and flat-twin touring roadsters enjoyed a solid reputation for quality engineering and reliability. However, the market was experiencing unprecedented demand for large capacity sports bikes. In comparison to the sports flagships of the Japanese, BMW's bikes appeared tame and a touch staid. The company needed a new pure sports motorcycle. In 1989, they unveiled the Kl, and what a striking, sensational-looking motorcycle it was. 

Designed to attract big sports bike enthusiasts and to keep BMW alive in the fiercest of markets, the Kl has succeeded on all fronts largely because if is so different.  The bike's distinctive bodywork, including the virtually-enclosed front wheel and bulbous tail section, is designed to make it aerodynamically efficient. Viewed head on, the bike presents a huge frontal area but this tapers away to the rear tail hump and gives an impressive drag coefficient of .38, a figure better than any other currently produced motorcycle. Its slippery shape helps it maintain a fop speed in comfort for the rider, who is well-protected from the wind-rush.  BMW needed an aerodynamic advantage because, in Germany motorcycle horsepower output is limited to a maximum of l00bhp.

The 1984, four cylinder K100 engine was extensively revised, doubling the number of valves to 16, reworking the combustion chambers and lightening the crankshaft, con rods and pistons, so the unit revved harder. Perhaps the most important change was the adoption of the Bosch Motronic digital engine management system as fitted to BMW cars. This combines control of the fuel injection .and ignition systems giving enhanced response, ample power and good fuel economy.  To match their new genuine 100 hp engine, BMW built a fine rolling chassis. The frame is uprated from the K100 series in that, although the engine still forms part of the frame with the single rear suspension arm pivoting on the casings, the frame tubing is in larger diameter tubing and the bike has a longer wheelbase and shorter trail.

The Paralever single-sided arm is articulated to avoid driveshaft torque reaction.  For front suspension and brakes, BMW fitted some expensive Italian components. The large diameter front forks are made by Marzocchi. The brakes - large 305mm floating discs gripped by four-piston calipers - are by Brembo. In addition, the bike comes with BMW's own, exclusive ABS or anti-lock braking system. Electronic sensors monitor the comparative speed of front and rear wheels and releases brake pressure up to seven times a second, preventing possible lock up of the wheels.

The ABS system is a boon to road safety and BMW are still the only manufacturer to have put ABS into production. It's been an option on oil their big bikes since 1988. .Using the widest wheels ever fitted to a BMW, the Kl responds \o being ridden aggressively. Despite an enormous wet weight of 5701b, the bike is surprisingly nimble and easy to ride. Its forte is the wide open, fast rood where its effortless max "nun speed can be fully exploited. It remaps a special kind of motorcycle. Originally only 2,500 were to be built but worldwide demand means the production figure is more.

The Kl is the only BMW ever built that's unable to carry hard panniers (the swoopy tail section prevents fitment though BMW do offer a soft luggage system that occupies the pillion seat making the Kl a true solo sportster). In response to demand from their traditional touring customers, in 1990 BMW released a 16-valve version of the K100RS. This bike can carry hard panniers. Apart from bodywork and styling, its specification is virtually identical to the Kl even though it looks nothing like it. As a modern superbike, the Kl stands alone - proud, defiant and very different.

Source of review : The worlds fastest motorcycles by John Cutts & Michael Scott

Review

Local lad Pope John Paul II would have liked to have roadtested the BMW K1, the German motorcycle manufacturer's first "super sports bike" and new flagship model.
But he was unable to attend the K1's international press launch in Italy "due to reasons of time", according to BMW officials, and I had the pleasure of riding the new bike in the Frascati countryside around Rome. The Pope has his summer home in Frascati but the hilly region is probably more famous for its lightly-sparkling white wine, also called Frascati, which featured more prominently on the agenda than riding time on the K1.
New product launches in the motoring industry are notorious for being long on entertainment and short on actual testing. But having said that the 80-mile circuit devised by BMW took in all types of road conditions, exposing the new bike's weaknesses as well as its strengths.
Walking over to collect my test bike from among the small regiment of KIs parked in a typically disciplined German line I was struck that the K1 would probably turn out to share the experience of the Ford Sierra. Upon its introduction the unusual-looking car was hated by everyone. In time it was loved by all. At the moment the K1l's strange looks are hated by almost everyone (except BMW officials).

The bike gives the overall impression of being curvaceous like many of today's most modern bikes. But individual parts are actually quite angular as on more old-fashioned mounts; witness the box sections in the tail which double as storage pockets and indicator mounts. Much more striking (to BMW officials) and horrific (to journalists) is the shocking yellow suspension clashing with the "Marrakesh" red or "Lagoon" blue bodywork and the 18-inch high decals spelling out "K1".

This dramatic design would have been less surprising if it had been introduced by a Japanese manufacturer because of BMW's reputation for understated paint jobs. However close Bee-Em watchers would have realised BMW was heading down the yellow paint road the busy bee RI00GS enduro mother of pearl KI00RS Special Edition introduced last year. Both of which have been successful despite their "un-BMW-like" colour schemes.

Picking my way carefully down the steep cobblestone road from the hilltop hotel, where the launch was held, I went wide on all of the tight zigzagging bends and too close for comfort to the edge on a couple of occasions. The K1's wide handlebars are good for manoevreabilrty at low speed but are stymied by a poor full lock. This is a bike that requires a two-point turn when turning round in a normal-width road. Perhaps realizing this BMW had stationed a man at the bottom of the hill to wave down traffic and let wobbling bikes through. Once out of the hotel drive, however, it was possible to open the throttle and see if the K1 really is a "super sports bike".

Motorcycle manufacturers have a voluntary agreement to restrict bikes for sale in Germany to 100 horse power. Being a conscientious German manufacturer BMW has gone one stage further and has also restricted its bikes for export to the same limit. This is also rather convenient as it means bikes do not have to be taken out of the assembly line and altered. Up to now, though, this policy has been purely academic as no BMW bike was capable of producing more than l00hp.
The K1, the first BMW with four valves per cylinder, changes all that. More valves meant the cylinder head could be made smaller four small circles take up less space than two big ones thereby helping to increase the compression ratio. The K1's compression ratio is a lot higher than the rest of the K-series at 11.0:1 compared to 10.2:1. Fuel is also burnt more evenly by a four-valve cylinder boosting power still further. Thus BMW's first 16-valve engine was capable of producing more than l00hp, according to BMW officials. But they made the decision to restrict it abroad as well as at home because the motorcycle industry is "being watched by politicians".

One official said: "The Japanese are skating thin ice. If they do not restrict the power of motorcycles themselves, they could tease politician too much and find restrictions enforced up "them which could ruin motorcycling." Instead BMW claims to have made up for the lack horses with the most aerodynamic fairing on two wheels.
Building up the speed slowly because there was a lot of loopy latin drivers and pop-up roadworks I found the K1 a very civilised "super sports bike". It was pleasantly smoother than its 8-valve K-series cousins at low revs and just as easy to ride in traffic because it has lost nothing in low-down power. In fact the sports bike actually has more. Torque has been increased from 64ft/lb at 6,000rpm to 74ft/lb at 6,750rpm. So there is no need to be constantly changing gear as on some rival super sports bikes. The 26-inch wide handlebars and only slightly leaned forward riding position make reasonably light work of traffic queues.

The action does not start until 5,000 rpm when the engine becomes noisier and disappointingly rougher. The bike goes faster than any other production BMW but does not set any speed records for the whole industry. BMW claims a 0-60mph time of under four seconds and a top speed of more than 143mph. Some testers claimed to have taken their K1s past 160mph on the motorway stretch of the test. But allowing for speedo inaccuracy at high speeds and journo bravado this probably adds up to a top speed of less than 150mph, well short of Japanese super sports bikes' 160mph plus.
The action runs out a lot earlier than on other super sports bikes if the rider obeys the K1's "redline", which is actually yellow in the gaudy colour scheme of things. This is at 8,500rpm whereas most superbikes go on to 11,000 or 12,000 rpm.

The reasons for the lower "yellow line" on the BMW is the along-the-frame engine's longer stroke and the 100hp limit.
BMW engineers claim their engine does not have to rev as much to produce the same amount of power as a Japanese bike. The K1 could go on revving past 8,500 rpm as the yellow line is more a moral warning than one of potential engine damage. Maximum power is not achieved until 9,000 rpm and a rev limiter does not cut in until 9,500rpm.
At speed the fairing does appear to do its job well. The more-than-a-mere mudguard (BMW prefers to call it a front fender) is wedge shaped to deflect wind past the rider's legs and back to the rear end of the tapered tail section. The windscreen with a lip at the top deflects wind over the rider's head despite being quite low. The aim is to enclose the rider in a bubble of turbulence-free air, which BMW has probably come closer to achieving than any other motorcycle manufacturer. The K1 has the lowest drag factor on two wheels; 0.38 with the rider upright and 0.34 with the rider prone. However the bubble bursts behind the rider's back, tickling his vertebrae. BMW officials excused this by saying: "The rider needs to feel some wind so he knows how fast he is going". I thought the rider looked at the speedo for this information.

The fairing made parking a problem because it got in the way of the rider's foot reaching down to the sidestand. The K100RS's stylish but almost useless moulded mirrors have been replaced by traditional ones on stalks, which may not look as good but provide much better rear vision.
I have mixed feelings about the K1's handling. Without fuel the bike weighs 259kg, which is 6kg more than the K100RS, now redefined by BMW as a "sports tourer", and only 4kg less than the K100LT tourer. This is 27kg more than the Honda CBR1000 and 37kg more than the Kawasaki ZX-10, probably the K1's closest rivals in the super sports class. A little of this weight has been better distributed; the radiator, front ABS modulator and toolkit have all been moved forward. However the extra weight still has to be carried and consequently the K1 does not feel quite as fluid as its rivals.
The steel frame has been stengthened by using larger diameter tubes than on other K-series bikes and the K1 is the first road bike to have BMW's clever Paralever, which accommodates a shaftdrive in a single-sided swinging arm. During the short test I noticed no flexing in the frame and the Paralever does appear to cancel out the torque reaction in the shaft, which in other shaft-driven bikes makes the rear-end rise and fall with acceleration and deceleration. But the new gas-pressure rear single shock absorber is under-damped causing bouncing bottom syndrome on badly potholed roads. And there is a lot of those in Italy (and the UK). The only adjustment riders can make to the whole suspension, front and rear, is to select one of the four spring preload settings on the rear shock. This is not much to fiddle with on an expensive motorcycle.

While the K1's Italian Marzocchi front fork legs are fractionally thicker than those used on the rest of the K100s (a whole 0.3mm) BMW is back to using one damper in each leg and riders are back to looking at the road when braking hard. BMW had cured its infamous problem on the K75S and K100RS Special Edition by having just one damper control the return of hydraulic damping fluid in both legs.

Having said that any fork legs would, have difficulty not diving when the new Brembo twin front discs are applied. The Italian sub-contractor's brakes are a vast improvement on BMW's own. The 12-inch discs are spirally perforated to save weight and have four pistons in each calliper like Suzuki to apply the brakes with plenty of pressure. The leading pistons are smaller than the trailing ones to even out brake pad wear. The rear single disc, which is still BMW's own, has been made thicker although I did not find this any better. Because of these changes to the brakes the software running BMW's computerized anti-lock braking system has had to be rewritten. BMW still appears to be having trouble with this as most of the test bikes did not have ABS and officials admitted the first production models (the test bikes were pre-production specials) will sadly not have the life-saving system either.

To make the K1 steer quicker than the rest of the K-series tyre sizes have been swopped. Instead of an 18-inch front tyre and 17-inch rear, the K1 has a 17 inch front tyre and 18-inch rear. But unusually for a more sports-orientated bike the wheelbase has been lengthened by two inches. This should makes the bike more stable at high speed but also counteracts some of the advantage of quicker steering. The radial tyres appear to grip well although hardly surprisingly there was no rain in Italy to put them to a tough test.

However the hot weather did show up a major problem on the comfort front. Since the 1988 Cologne bike show, when BMW unveiled the K1, extra vents have been put in the fairing in an attempt to to draw hot air from the engine away from the rider. But they are still not enough. Perhaps because of the efficient streamlining a pocket of hot air stays around the rider's shins. In cold weather this will be welcome but on hot days it can become unbearable. My first requirement after the test ride, which lasted only two hours, was a cold shower.

Even though the K1 is intended as a "super sports bike" and rules out serious touring because it cannot take panniers, I think it will fall in the sports tourer class. For credit card travellers and solo riders. Couples will have to be prepared to travel very light (BMW boasts the luggage pockets will take a waterproof oversuit but that is about all) or the traditional BMW rider will have to be prepared to leave the Missus behind. If he does he can fix BMW's K1 "luggage system" on the pillion, which provides 42 liters of capacity (about one and a half panniers). When either a passenger or the luggage system is not being carried a seat hump adds to the sporty looks.

Comfort over great distances is not helped by the fact that BMW has not cured the vibration problem thoughout the whole rev range. The footpegs are particularly bad at transmiting vibes to the rider while the new handlebars seem to do a better job at keeping them at bay. But the riding position is far from a sports crouch, so it should not cause cramp to set in, and the seat is well padded, despite being more than an inch lower than on the K100RS and K100LT.
 The lower saddle answers a long-standing complaint with K-series bikes that shorter riders have to stand on tiptoes at junctions. However even taller riders should continue to watch where they put their feet. Tom Isitt, editor of Motor Cycle lnternational, wanted to park his K1 at the edge of an Italian lake for a photograph. He put his foot down on what he thought was a weed-covered verge, only to discover the weeds disguised a two-foot deep drainage ditch. He and the K1 plunged. Remarkably neither he nor the bike were hurt. Only the K1 decals were scratched which says a lot for the new fairing's impact resistant qualities.

The K1 appears to have leg-protectors built in, although BMW officials would not admit that is exactly what they are. The press kit talks of "knee pads in the fairing serve to absorb kinetic energy in the event of a head-on collision" (and a sideways fall into a ditch?). What the Motor Cycle Association, which is opposed to the Government imposing leg protectors, will think of another of its members giving in and fitting such devices (Norton already does) we will have to wait and see.

As BMW mechanics kept the test bikes topped up with unleaded petrol I have no independent verification of fuel consumption. BMW admits the K1 is thirstier than other K-series bikes but claims it is still capable of more than 40mpg.

A nice touch is the grease nipples fitted to almost every part that needs regular greasing. A disappointing one is the lockable lids on the three luggage pockets; there is a third one in the front fairing. Because they are ill-fitting and do not hinge to the fairing many are likely to be lost. At least one journalist came back from the test without one.
One thing it was impossible to assess on a short test is BMW's Motronik computer system, which manages the K1's engine. This has been adapted from BMW's cars and is said to be a step up from the fuel injection LE-Jetronic system used on the rest of the K100s.

BMW (GB) Ltd has ordered 200 of the 4000 K1s BMW plans to make this year. But it does not expect to receive more than 150 (production targets nearly always being overestimated) and they are not expected to arrive here until the end of August at the earliest because the UK is well down the parent company's list of priorities. Germany is getting the first bikes to roll off the assembly line about now, closely followed by France and Italy. Even little Sweden is ahead of the UK.
This gives executives at BMW's UK headquarters in Bracknell, Berkshire, more time to fix a price for the K1. But privately they say they want "to keep it just under £8,000 with ABS". This would make the flagship K1 nearly £1,000 more expensive than the current top-of-the-range bikes, the K100LT and K100RS Special Edition. Initially it is planned to offer ABS as a £595 option — it has to be with the software problems — but by next year, when it is planned to bring in 300, it could become standard.

Source Motorcycle Review 1989