1000cc Slash 5 from Oren’s Performance Bikes…
It might be hard to imagine now, but in the 1960s, BMW’s motorcycle division was at risk of being shut down, languishing with poor sales and outdated designs. In order to save the business, BMW brought in former Porsche engineer Hans-Günther von der Marwitz to design a new series of two-wheeled machines to be produced in a dedicated factory near Berlin.
For the 1970 model year, the new BMW “Slash 5” series appeared, consisting of the 500cc R50/5, 600cc R60/5, and 750cc R75/5. Though the bikes retained the signature flat-twin boxer engine layout, they were completely new:
“The new ‘Slash-5’ series of BMWs offered 12 volts, electrical starters(!) as well as the retained kick starter, telescopic forks, and improved brakes.” –Jeff Dean, BMW MOA co-founder
The Slash 5 also had a lighter tubular steel frame, and the engine boasted a new forged one-piece crank, chain-driven camshaft, iron-lined light alloy cylinder barrels, and connecting rods from BMW’s 2.8-liter six-cylinder automotive engine. The Slash 5 would bring BMW’s motorcycle line back from the brink of extinction and become a favorite of riders, collectors, and customizers.
Recently, we heard from our new friend Oren, an Israeli industrial designer who builds motorcycles in his free time:
“I established a small workshop called “Oren’s Performance Bikes.” I mostly build BMW Airheads, for myself, and for owners who want to customize their bikes.”
This ’72 R60/5 arrived in Oren’s workshop as a non-runner, having sat neglected for several years. As a slew of performance upgrades were planned for the engine, the owner requested a bike whose handling and style would befit the improved performance, giving Oren the creative freedom to make it happen:
“The plan was to build a classic cafe racer that on one hand would keep the classic character of the Slash 5’s, and on the other hand, will be a mean-beast under the classic appearance.”
Oren stripped the 50-year-old BMW down to the bare frame, installing a shorter and lighter SE subframe, rear-set controls, Öhlins shocks, ’82 BMW double-disc forks, and a gorgeous set of BMW snowflake wheels.
Engine highlights include a Siebenrock Power Kit, boosting displacement from 600cc to 1000cc, along with R80 heads, 32mm Bing’s carburetors, and a rebuilt 5-speed gearbox swapped in place of the 4-speed stocker. Siebenrock says their kit alone is good for a power increase from 40 to 64 horsepower (+60%) and at least 30% more torque.
On the electrical side, the bike is running BMW R80GS controls and electrical harness, with much of the wiring internally routed for a clean look, along with a small lithium battery in the rear cowl and EME electric ignition.
Oren says this once-sleepy R60 has transformed into a whole new animal:
“The result of the build is a light, compact, and powerful bike that accelerates like a tiger on steroids. The /5 spirit remains but the bike’s performance and handling are light years ahead of the original drowsy bike.”
Below, Oren gives us the full story of this flat-twin café racer.
BMW Slash 5 Café Racer: In the Builder’s Words…
From Oren of Oren’s Performance Bikes.
About myself
My name is Oren and I’m from Israel. I am an industrial designer in my main occupation and a bike builder in my spare time. I established a small workshop called “Oren’s Performance Bikes.” I mostly build BMW Airheads, for myself, and for owners who want to customize their bikes.
About the bike
The BMW R60/5 is a classic motorcycle that was produced by BMW from 1970 to 1973. The bike was known for its smooth, torquey engine and comfortable riding position.
About the build
This bike was born in ’72 and came to my hands as a non-runner after standing aside for several years. The plan was to build a classic cafe racer that on one hand would keep the classic character of the slash 5’s, and on the other hand, will be a mean-beast under the classic appearance.
The owner allowed the freedom to operate and wished for a modern overall behavior to fit the power and performance of the engine that was intended to take place.
To create this cafe racer version of the R60/5, I started by stripping the bike down to its bare essentials, removing any unnecessary parts and accessories. Next, the sub-frame was removed and replaced with a shorter and higher one from SE (Sport Evolution Germany).
The stock handlebar found itself in the dump, and a new clubman-style Rizoma was installed.
The rear shocks were replaced with state-of-the-art Öhlins shocks, and the front fork was replaced with an ’82 BMW bike. That facilitated the adoption of a snowflake wheel and dual disc brakes at the front. At the rear, another snowflake wheel went in and a set of rear-seat foot pegs were installed.
The engine was totally stripped, powder coated with matte black color, and was totally rebuilt. There is no trace left from the original 600 cc’s, as it was installed with a new Siebenrock Power-kit, R80 heads, and 32 mm Bing’s carburetors.
The 4-gear gearbox went on the spare parts shelf and a totally rebuilt 5-speed gearbox took its place behind the powerful engine.
The old and tattered wiring harness was replaced with a new R80 G/S one, same as the handlebar switches and other wiring components. Peripheral wiring was routed through the chassis tubes to give a clean and cable-tie-free look. The charging system was improved with a Rick’s rectifier to fit the small lithium battery, which is accommodated in the rear seat cowl. A brand new EME electric ignition was installed to ease starting and improve overall performance.
In the light department, the original headlight bucket sustains the BMW classic /5 look with its chrome lamp guard. At the end of the handlebar you can find the Motogadget turn signals, same as at the back of the sub-frame. Another modern-classic feature to complete the overall styling is the Motogadget Chrono Classic speedometer, which replaced the old and under-performing speedo unit. The rear light is hidden under the cowl to keep a clean-looking streamlined silhouette.
The front fender is held by the original /5 fork brace and a short rear fender completed the classic look. The seat upholstery was made of goat leather and was customized to fit the overall design.
The result of the build is a light, compact, and powerful bike that accelerates like a tiger on steroids. The /5 spirit remains but the bike’s performance and handling are light years ahead of the original drowsy bike.
Nice.
Vintage BMW Slash 5.