According to novelist Robert A. Heinlein, “Ability is a wonderful thing, but its value is greatly enhanced by dependability. Ability implies repeatability and accountability.” Makes sense for a guy who made his bones writing sensible sci-fi, with strong themes of duty, dependability and getting the job done.
When Heinlein said that, he could have been describing BMW’s K-series, either the three-cylinder K75 or the four-cylinder K100, like this 1992 model for sale on the west coast.
To be sure, when the K bikes debuted in the early 1980s, they didn’t have the same performance as the hot rods cranked out during the same time in Japan. However, they were a massive evolutionary leap over BMW’s airhead models, and still retained the company’s legendary reliability. A lot of K bike fans would say the K75 and K100 actually enhanced BMW’s reputation, perhaps becoming the company’s most reliable machines ever. It’s like they were built to Heinlein’s demands: improved ability, but with dependability that matched or even exceeded the previous designs.
Why was the K series so reliable? BMW benefited greatly by cutting ties to previous engine layout principles, and designing what was basically an inline car engine to power the bike (early prototypes were actually powered by a Renault motor). It was designed to excel, not to molly-coddle an existing customer base that wanted the same old thing.
Unlike across-the-frame inline engines on Japanese bikes, the front-to-back orientation of the Beemer design made maintenance easy. You could quickly access the valve cover on the left-hand side of the machine without needing to contort yourself around frame downtubes.
The K75 and K100 were pretty much the same engine, except the K75 had an added counterbalancer and one less cylinder. Most of the parts will interchange between these two engines, so BMW kept production costs down and was able to implement improvements to both models throughout production.
Of course, there were still lemons, and some K bike owners don’t have fond memories of their Bee-Em-Trouble-You, but many, many of these bikes went well over 100,000 km on the odometer. In the early days of the Iron Butt Rally, these would have been one of the mounts of choice.
The bikes’ reliability might have actually contributed to some of the failures, as owners got so used to minimal maintenance that some must-do work would be ignored. The driveshaft is a particular point of grief here; ignore routine maintenance at your peril. Just because you don’t have to lube it as regularly as a chain drive doesn’t mean you can forget about it.
Although Japanese bikes might have been faster, the K series did have plenty of technology that was revolutionary for the time, including some of the first factory fuel-injection systems as well as antilock brakes. ABS wasn’t included on every K bike, and it was definitely more crude than the systems available today, but in the motorcycle world, it was a big leap forward.
However, while the K series was full of firsts for BMW, it was getting long in the tooth by 1992, and this particular bike is from the last run of K100 machines. While BMW still produces K bikes, the K100 was done after 10 years in the line.
Regarding this particular bike for sale, the photos show BMW’s clunky ABS unit on the left-hand side of the bike, and that’s a good thing. It also comes with a set of no-nonsense hard bags, and appears to have a mini-rack over the tailpiece — all very good stuff if you want to tour, and hard to find on a long-out-of-production bike.
Being a 1992 model, this particular machine should have the higher-performance 16-valve engine, although you’d want to confirm that with the seller. This would be the same engine that debuted in the K1; maintenance is a bit more of a hassle, but the benefit is improved performance of about 100 hp.
There’s a lot of other stuff you’d want to confirm with the seller, especially regarding maintenance. This bike has very low mileage — at 24,500 km on the odometer, its life is just starting, theoretically. But if the driveshaft lube has been ignored, or the bike’s many rubber seals have dried out and started to leak, you could be in for a lot of irksome maintenance or expense.
In some ways, the low mileage almost works against the seller; many buyers want a K bike that’s been ridden regularly, because that’s a good indication that maintenance has been kept up. The ultimate deal on an older K100 might be a machine that was ridden about 20 km a week, just to keep everything in working order.
But if everything checks out, the $3,500 asking price is probably very fair, as the bike appears to be in good nick. The only way to know is to contact the seller, and make an appointment to see it for yourself. Go to the autoTRADER ad and and you can set that up.