1988-89年BMW K1

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

Performance Bike review 1987

Initially announced at last year's Colonge show, BMWs Kl is now officially launched. BMW are not noted for pushing the outer limits of radical motorcycle design, but they are one of the few European manufacturers who virtually ignore the belligerence of the Japanese and consistently get away with it The Kl is therefore an uncharacteristic and significant move for BMW. It is not only a probing finger into the hotly contested 'Super Sports' market, but also a clear confirmation of their commitment to the future of the K series.

The factory proudly announced the Kl to be the top of the range, and to signify the 100,000th K to be manufactured. There are no plans to cease production of the R series twins either.
More characteristically though, BMW made it quite clear that the Kl, as far as they're concerned, is not intended as direct competition for the Japanese monster power bikes. Quite where all this leaves the Kl positioned in the market is unclear, although I suspect it's with all the other BMWs. Possibly a fairly safe place to be.

BMW very kindly decided to launch the Kl in Italy, and suitably stuffed with quantities of pasta, various members of the world's press were squeezed into their leathers and allocated a Kl each for three hours' riding in the hills around Rome.
As we wobbled in convoy down the steep hotel slip road, the first impression I got of the Kl was the unfamiliar feeling of having to reach backwards for rearset footpegs on a BMW. The second was the vicious power of the twin four-pot Brembo calipers on fully floating discs; something one is accustomed to on Japanese bikes but definitely a first for BMW. Their ABS anti-lock braking system is available as an extra on the Kl and it will be interesting to see how it performs on this kind of set-up compared to the less dramatic K100 system. According to BMW 60% of their new K series customers now order ABS.

The Kl's motor is basically a K100 liquid cooled flat-four, fitted with a sixteen valve head
 instead of the KlOO's eight  and a central digital engine management system, with a defect recall memory, that controls both fuel injection and ignition. Producing a claimed lOObhp at 8,000rpm, instead of the eight-valve's 90bhp, the Kl is sticking to a voluntary lOObhp maximum power output for motorcycles produced in West Germany (I don't think the ones produced in the East have much to worry about).

As BMW are one of the few bike manufacturers whose power and performance claims are quite realistic this, plus the claimed 142mph top speed, may well be true.
Riding the bike briefly on public roads it is hard to say how much power is there, and without comparing it to a K100, even harder to say how much more it has over the eight valve. However I am in agreement with BMW that it produces enough. Below 4,0O0rpm it's a bit flaccid, but between 4,000 and the 9,000rpm redline power is smooth and progressive.

A tingly vibration can be felt between 3,000 and 5,000rpm, although this was not obtrusive. What was obtrusive, and I wasn't the only one to find it, was an annoying false neutral between fourth and fifth gears. I found it at least five times and was able to coast along without any number showing on the digital gear indicator and without any signs of the box changing up or down un-aided. If you remember it's there then it doesn't really matter, but on a hightech ￡7,500 bike should the gremlin be there in the first place?

Perhaps the most significant step forward the Kl has made for BMW is in suspension and handling. New, braced, 41.7mm Marzocchi forks, developed especially for the Kl, and BMW's Paralever rear suspension attached to a beefed-up K100 frame, are by far the best K series set-up yet. The appalling state of some of Italy's mountain roads would give some trail. under hard acceleration. The ride is still smooth and soft, not unlike the bigger Japanese sports bikes. Steering is light and assisted by unusually wide, 30in handlebars.

Much emphasis by BMW has been put on the wind tunnel developed aerodynamics which are perhaps not entirely apparent when first riding a bike that has them. But after a while it did occur to me that there was actually very little turbulence bashing my head about, and at high speed the bike appeared to be stable and smooth. I don't know about crosswinds because there weren't any.

Good aerodynamics also means good fuel consumption. BMWs figures for the Kl's drag coefficient are 0.38 with the rider upright and 0.34 prone. If you understand that then you know more about such things than I do.

I'm not too sure about the paint scheme though. It seems to me that the bulboid shape of the bodywork is sufficiently confusing without having con-trasty colours add yet more shapes and patterns. The yellow gearbox, shaft and hub is positively Massey Ferguson.

Two more very worthwhile improvements the Kl has over the K100 are a central steering
lock (unlike other BMWs which have a lock so stupid it defies description), and that the blue smoke emissions familiar to post-side-stand-use K owners are a thing of the past. This is due to the addition of oil drain holes in the vicinity of the piston rings. All future K series models will have these drain holes.

Unworthy items on the Kl are the tacky and fiddly mini panniers in the rear body panels. The idea of having some stowage space, albeit small, is a good one, but the lids are not hinged and if not correctly refitted will fall off. The six litre capacity compartments could also do with a soft lining to isolate vibration. This sort of poor design would not appear on a BMW car so why should it on a bike? An additional stowage compartment is included in the front fairing for holding tools. A semi-rigid, 42 litre pannier set is available as an extra although conventional Krauser style panniers, it is said, would not suit the Kl's aerodynamics.

The Kl is certainly not a tarted up K100, and is without doubt a thoroughly developed concept on the whole. Whether its radical appearance will attract those previously uninitiated to the BMW marque is hard to say. It is perhaps more likely, taking into account its price, to attract those who already have a K series and lust for something a little more daring.

Source Performance Bike review 1987