FEATURE – 1976 BMW R100/7 custom
Words: Mike Ryan
Photos: Brian Dyer
Ideas are easy. Turning them into reality is the hard bit. Or, at least it is for most of us. But most of us aren’t Malcolm Oastler. You see, Malcolm is someone who not only has great ideas, he’s someone who can bring those ideas to life, as evidenced by the creation shown here – a creation that JUST BIKES inadvertently inspired!
Child Prodigy
We usually associate child prodigies with 8-year-olds who can play the piano like a master, or kids barely out of kinder who can solve the sort of maths problems most of us can’t even fathom.
There are different types of genius, though, so surely prodigy status can apply to a kid who builds his own motorcycle while still in primary school? That’s exactly what Malcolm did.
As a 12-year-old in the early ’70s, the young Malcolm could see that his push-along scooter just wasn’t cutting it, so he added a wheelbarrow wheel and 2-stroke engine off the family’s Victa mower to create a motorcycle. OK, calling it a “motorcycle” may have been a bit of a stretch, as brakes, gears and suspension were absent, but it was a powered two-wheeler – and a hell of a lot of fun!
Malcolm describes that lawnmower-powered creation as his first true engineering project and has such fond memories of it that he decided to create a replica a few years back.
Between that first creation and its modern reproduction, Malcolm certainly didn’t sit on his hands. A passion for motorsport saw him involved in open wheeler racing, specifically Formula Fords, and he spent time connected to our local touring car scene, too.
Graduating from university with a first-class honours degree in mechanical engineering, Malcolm took his talents to the UK, where he spent two decades from 1985. Initially aiming to be a driver, his design skills saw him trade the cockpit for a computer and CAD software.
Hired by renowned racecar builders Reynard, Malcolm would be responsible for, amongst other things, a Formula 3000 chassis that delivered five international constructors’ titles.
In 1998, Malcolm joined Formula 1 as chief designer for British American Racing, with time at Jaguar Racing following before he retired from the F1 circus in 2004.
Now enjoying a less hectic life in rural New South Wales, Malcolm’s design and fabrication talents haven’t escaped him, they’ve just been taken in different and altogether quirkier directions. The aforementioned Victa scooter is one example, with another being an ex-Police BMW K1100 that was turned into an Art Deco-inspired, fully-faired custom that’s been dubbed the ‘Oastler Streamliner’.
There’s been a fair few bikes along the way, too, including a little Benelli 250 and Honda CB 250RS, while a Suzuki Katana 650 and Yamaha FJ 1200 served as regular transport while Malcolm was based in the UK. More recently, Malcolm treated himself to a Kawasaki ZRX 1200S.
But getting back to Malcolm’s creative spirit, it’s certainly different to most of us, who are just content to dream about fantasy projects. Malcolm can’t let it end there though. He says that once he gets an idea in his head, he has to bring it to fruition: “I get an idea that this will be fun - and then it just has to happen!”
The bike presented here is another example of Malcolm taking an idea and making it a reality.
Triumph Failure, BMW Success
Back in 2012, Malcolm decided he wanted a Triumph Thruxton, so picked up a copy of JUST BIKES to see what was available. No Thruxtons were listed for sale in that issue, but there was something entirely different that caught his eye. What Malcolm had spotted was a custom bike powered by a Ford flathead V8 engine.
“It wasn’t a very revealing photo, and it turned out that what I thought was a V8 café-racer styled bike was actually a hideous rigid tailed chopper,” Malcolm recalled. “But the idea was born, so I had to go ahead and build the bike.”
The bike Malcolm most likely saw back then was one of the Olson V8s that were produced in small numbers in the USA in the ’90s. Usually based on old Harley big twin frames and running a single-speed transmission, a few of these retro-look cruisers have come to Australia in recent years.
However, Malcolm had decided that his V8 custom would be a café racer, not a cruiser, so that meant a different base bike was required.
Settling on an older R Series BMW, for its gearing and shaft drive, Malcolm placed a wanted ad in the local paper, which produced a response almost immediately - a 1976 R 100/7 with twin front discs and the desired tall final drive that had sat unused in a shed for six years.
For the engine, Malcolm did start looking for a period-correct Ford V8-60 (for 60 horsepower), but was informed by a mate from his Reynard days that these engines are better as boat anchors and he should be looking at a Simca V8 instead.
The Simca connection is a story in itself, but basically, Simca took over Ford Motor Company’s French manufacturing operations (Ford SAF) in 1954 and inherited the flathead V8 as part of that. Taking that basic side-valve V8, Simca improved the cooling, induction and other elements to kick power up to 85hp with a 2-barrel carby fitted.
Reaching out to the Simca Car Club, Malcolm was informed that a club member had just put his 1959 Simca Vedette on the market and was willing to sell its engine separately.
So, within a few weeks of making the decision to build the bike, the two key components were acquired: “Once I get started, it all happens in a bit of a rush!” Malcolm laughed.
Split in Two, France meets Germany
While making an all-new frame to cradle the V8 could have been possible, Malcolm decided to simply cut the BMW frame through the middle, then use the V8 engine as a stressed member connecting the two halves.
On the engine, tearing it down revealed some wear and that it had been bored out around 20 thou sometime in the past, so during the rebuild, Malcolm increased that to 50 thou, shaved 1.5mm off the heads and fitted new pistons, rings and bearings. The result is that what was a 2.4-litre engine when new is 2.5 litres now and the previous 7.2:1 compression is now a headier 8.5:1.
With the factory sump being a bit too big (and a bit too ugly) to suit this build, Malcolm fabricated a new alloy sump to suit, incorporating attachment points for the frame in the process. Malcolm also fabricated the three-exit exhaust headers and added cone-style silencers for the right look. Three pipes from four ports? No, that’s not a mistake: the middle two exhaust ports are siamesed into one on these engines.
A Subaru starter motor now cranks the engine over and a modern Piranha electronic ignition handles the firing, while the alternator is from a Suzuki Swift/Holden Barina and projects out from the front of the engine. To keep this protected against water ingress and stones thrown up by the front wheel, a custom cover was made to suit.
While a period-correct Solex 2-barrel carby remains, a vey slim air filter had to be added to ensure it didn’t foul the fuel tank. With the same consideration in mind, the water passages from the engine to the radiator were redirected (forward, rather than up) and reduced in diameter, but with a modern electric water pump fitted, they actually work more efficiently, combined with a fan-assisted radiator that Malcolm built from scratch.
To marry the V8 engine to the BMW 5-speed transmission, the Simca bellhousing was used, but machined back to a depth of 50mm, with an adaptor plate welded on and modifications made to take the starter motor. A mate of Malcolm’s in New Zealand made up a new flywheel to fit the Simca crank to the BMW clutch, with Toyota Corolla ring gear completing the connection. It’s worth noting that the gearbox internals remain stock BMW - no mods were needed.
Cutting and spreading the frame to suit the engine has increased to bike’s overall length by 300mm compared to a stock R100/7, with the aforementioned, custom-made attachment points on the sump and bellhousing for the frame supplemented by repurposing existing fittings for the water pump and inlet manifold on the top end of the engine. With minor frame additions incorporated to suit, Malcolm says the result is an incredibly stiff chassis.
The battery remains in its usual place under the seat, but that seat is another piece that Malcolm built from scratch to suit the café racer theme.
The handlebars were made from scratch, too (more on that shortly), as was the fuel tank. Fabricated from 1.6mm sheet aluminium, the tank is an impressive 800mm long, but not as expansive as you might think, as much of the underside is hollowed out to accommodate the carby and air filter.
The BMW brakes were left unaltered, as was the suspension (more on that shortly, too), with the 19-inch/18-inch front/rear wheels reshod with Metzeler rubber.
Finishing touches included things like bar-end mirrors and a new tail light, as well as adding ampmeter and water temp gauges. The revcounter was blanked off as its largely irrelevant for the V8. In its place is a ‘Rat Café’ graphic reflecting the name Malcolm applied to this creation from the outset.
Working on it diligently, but not slavishly, the bike was complete and ready to ride in mid-2014.
Rolling Changes
Even before he completed this build, Malcolm would find himself bemused by people’s reactions to it, which usually ran along the lines of “That thing will be too heavy to ride with that V8”. Yes, Rat Café is a heftier piece of kit than the BMW it started off as, but at 300kg, it’s no heavier than a modern Harley tourer: “For a water-cooled, iron block V8, that’s not too bad, really,” Malcolm laughed.
The first shakedown rides revealed some minor, but immediate problems, starting with bars that needed reprofiling as they would put one hand out of reach on full lock.
The drive shaft was slightly misaligned and the clutch was slipping, but the other main issue was the factory suspension, which proved to be too plush for the extra weight.
“It wasn’t the magic ride that I had envisaged!” Malcolm recalled.
The simple solution to the handlebar reach problem was to bend up a new one with more pull-back and less width, while firmer springs would solve the suspension issue. New, stiffer springs were added at the front, while a complete pair of Ikon shocks were swapped in at the rear. Combined, they transformed the ride.
Rat Café performs incredibly smoothly now, with that big, torquey V8 making low-speed roll-ons easy – you can even take off from a standstill in fifth gear. And the gorgeous engine note is unlike anything you’ve ever heard on two wheels.
Other niggly little issues were addressed in turn over the following year, so when Malcolm rode the bike down to Canberra for engineer approval, it ate up the miles on the journey (100km/h+ is achieved with ridiculous ease) and sailed through inspection without an issue.
“Having these creations road registered, it’s almost like an endorsement,” Malcolm explained of his approach. “Having the finished product driveable or raceable is a really important part of what I do.”
Boats, Cars, Bikes
Since registering this bike, the only problem Malcolm’s encountered is that he doesn’t spend enough time riding it, hence the decision to sell (see breakout).
As mentioned, Malcolm finds more joy in bringing new ideas to reality than reflecting on old ones. Since completing this bike, those new ideas include a ¼ scale replica speedboat and a ’34 Ford roadster with a Lexus V8 and spaceframe chassis.
Malcolm’s current project is ‘Ninjamobile’; a Goggomobil Dart that’ll be powered by a Kawasaki ZX10R engine. Now that sounds wild! Cars are outside the scope of JUST BIKES, but I reckon we might have to make an exception with that one when it’s completed.
FOR SALE
Malcolm rarely keeps the customs he builds, so this one went on the market some time ago. More recently, it was listed with JUST BIKES.
In fine running condition, with engineer-approval and full NSW registration to March, 2020, this one-off BMW is ready for the new owner to enjoy (look for ‘BMW V8 Rat Café’ on YouTube for build progress and running footage).
The asking price is $32,000. Call Malcolm on (02) 6493 2324 for details.
View the advert online at https://www.justbikes.com.au/ with the ad code JBM5012690.
