By Jeff Dean, International Council of BMW Clubs Friend of the Marque
BMW Used to Manufacture Shaft-Drive Thumpers!So you think that Bayerische Motoren Werke (BMW) only makes shaft-drive twins, triples, and fours, and more recently an internationally produced chain-drive F650 single? If you do, you are wrong, combustion breath!
From the 250cc OHV R39 (photo above, left) of 1925 through the 1954 R25/3 (photo above, right) to the R27 of 1967, BMW made shaft-driven thumpers ranging from 200cc (1931 R2) to 400cc (1932 R4) in almost as many permutations as its more famous opposed boxer twins. Most of the models, however, had bores and strokes both of 68mm, producing 247cc. Frame and suspension changes paralleled those of the twins
What was the last single-cylinder shaft-drive BMW motorcycle model made?It was the relatively powerful and elegant R27, a 250cc OHV vertical single with the only rubber-mounted thumper engine BMW ever produced. The engine pumped out 18 horsepower, the highest ever for a shaft-drive BMW single. BMW manufactured 15,364 R27s over the production years of 1960 through 1966 (some of the 1966 R27s were sold as 1967 models).
The illustration above on the right shows the cover of a 1960s BMW R27 sales brochure.
Compared to other manufacturers' thumpers, what were some of its unusual features?BMW never did run with the crowd and always struck out on its own path. This is evident in its R27. Its enclosed shaft final drive is extremely rare fora thumper, of course. But it also had a triangulated Earles (named after English designer Ernest Earles) front fork; so the motorcycle had a front swingarm as well as a rear swingarm. When you squeezed the front brake lever hard not only did the front end not dive, it actually rose slightly. Thus, braking was a very steady activity, though the brakes were weak by today's standards. The R27 engine's crankshaft was laid out fore-to-aft, not side- to-side; also a rare feature. This way, the crank and the final shaft were in line, and drive forces did not have to be run through a set of 90-degree gears. Also, the kick starter swung out sideways instead of parallel to the frame, so kick starting an R27 is a rather easy and danger-free affair.
What other BMW singles were manufactured after World War II?In all, BMW produced six shaft-drive thumpers after the war, all with similar 250cc OHV engines. The first, in 1948, was a copy of the pre-war R23 and was designated the R24 (engine numbers 200 009 - 212 007). It was unique in that it had no rear suspensionthe only postwar BMW so unequipped (see photos below). Thereafter, from 1950 to 1956, came bikes with rear plungers and front telescopics, all having exposed shaft drives and bell-bottom front fender skirts. These were the R25 (engine numbers 220 001 - 243 400), the R25/2 (engine numbers 245 001 - 283 650), and the R25/3 (engine numbers 284 001 - 331 705).
Here is a somewhat rusty and dilapidated BMW R24 that I spotted and photographed in 1969.
In 1956 BMW introduced a completely revamped thumper, the R26 (engine numbers 340 001 - 370 236), with improvements paralleling those introduced at the same time in the boxer twins. The R26 came with an enclosed drive shaft, rear swingarm, and front Earles forks. A new headlight nacelle came with a sliding black plastic over the ignition key, and the bell-bottom front fender was dropped along with the mechanics' hand shifter. The engine of the R26 was bolted directly to the frame, and the engine wailed away with 15 horsepower.
Based largely on the R26, the R27 added rubber mounts for the engine, which markedly reduced the R26's vigorous rider massages, and boosted horsepower by three to 18.
What are the specifications of the R27?Here are the main ones:
Curb weight with fuel, oils, tools 356 pounds (162 kg.)
GVWR 716 pounds (325 kg.)
Fuel tank capacity 4.0 US gallons (15 liters)
Engine oil capacity 2.6 US pints (1.25 liters)
Engine oil type SAE 40 (86°+), SAE 30 (32°-86°), SAE 10W30 (below 32°)
Transmission oil capacity 1.3 US pints (650cc)
Rear drive unit oil capacity 125cc
Transmission and rear-drive oil type SAE 90 gear oil or SAE 40 engine oil
(depending on the year of manufacture)
Wheelbase 54.3 inches
Overall length solo 82½ inches (2090 mm)
Handlebar width solo 25.6 inches (660 mm)
Overall height solo 38.4 inches (975 mm)
Saddle height 30.2 inches (770 mm)
Ground clearance 4½ inches (115 mm)
Maximum brake horsepower 18 HP at 7,400 RPM
Bore and stroke 68mm × 68mm
Cylinder capacity 247cc (15 cubic inches)
Spark plug Bosch W240T1, Beru 240/14, or Champion L85
Intake valve clearance, cold engine .006 inches (0.15 mm)
Exhaust valve clearance, cold engine .008 inches (0.20 mm)
Compression ratio 8.2:1
Top speed 80 MPH (130 km/h) depending on conditions and wind
Predicted mileage 60 miles per US gallon (DIN 70030)
Tires 3.25 x 18, front and rear
Battery 6 volts, 9 Ah.
Headlamp 6 volts, 35/35 watts
What is my R27 worth?Without doubt, this is the most common question I receive from R27 owners.
The marketplace for vintage and collectible BMW motorcycles always is influx. Moreover, the value of a particular old BMW cannot possibly be estimated without examining it in person. Even then, there is no certainty as to what it might bring if it was put up for sale.
The Antique, Classic, & Special Interest Motorcycle Price Guide (1997 edition) lists R27s, regardless of year, as being worth from $2,000 to$5,300, depending entirely on condition. That latter is for an excellent R27 close to a perfect original or a very well restored motorcycle. The former (lower) value is for an R27 that, starts, runs, and rides OK but needs some work. ... This is a complete motorcycle with most sheet metal and body parts being correct, [emphasis mine] but only in fair condition. In my experience, the most valuable vintage BMW motorcycles,including R27s, are those that have all original parts, are in excellent condition, but have not been restored. No matter how pretty, a restored R27 is not worth as much as an excellent unrestored R27 — and this is true of any vintage motorcycle, in my opinion.
N.A.D.A. Appraisal Guides now publishes the Antique, Classic, and Special Interest Motorcycle Appraisal Guide. Regardless of year, this guide places the value of an R27 between $2,200 and $6,000 depending, again, on condition.Interestingly, this guide places the value of an R26 higher,even though many more were manufactured, and the value of an R25/3 lower than that of an R27. The N.A.D.A. guide is updated three times a year and may be ordered by calling 1-800-966-6232.You can also reach the publisher through its N.A.D.A. website.
So-called restorations vary widely in their quality and accuracy. Although I have seen a few, it is uncommon to see a restored BMW motorcycle that cannot readily be identified as not being original. I have also learned from experience that the least expensive way to acquire an excellent R27 or other vintage BMW is to spend enough money to buy the very best specimen you can in the first place. Bringing back a beater or a basket case is the most expensive way to go because of the enormous cost of original parts and labor.
If I want to buy an R27, how might I locate one?R27s are rarely found through newspaper advertisements. Your best sources are local BMW club membership, the magazine of BMW Motorcycles Owners of America, BMW Owners News, the magazine of the BMW Riders Association,On the Level, or the newsletter of Vintage BMW Motorcycle Owners, Vintage BMW Bulletin. The addresses for all these organizations may be found through the Internet BMW Riders (IBMWR) web site.
The IBMWR site also has a classified advertisements page that includes a listing of vintage BMW motorcycles for sale, which often includes R27s.
Here is Allan Atherton's heroic saga of restoring a BMW R27.
Where can I find parts and information for restoring an R27?Here are five internet web sites of places that offers parts and restoration services for vintage BMW motorcycles, plus other links for more information:
Mark Hugget BMW, Switzerland
Blue Moon Cycle, Georgia
Bob's BMW, Maryland
Uli's Motorradladen, Frankfurt, Germany
Bench Mark Works, a.k.a. Craig Vechorik, Mississippi
BMW Motorrad, Missouri
The BMW R27 Motorcycle A dedicated R27 web site!
Who should I contact for further information about the R27?Click here for 1966 BMW R27 owners manual.
Click here for a 2012 Motorcycle Classics article on the R27.
Click here for the R27 article on Wikipedia.
Hier klicken, um den R27 Wikipedia Artikel auf Deutsch zu lesen.