This is an article I wrote about the bike for Cafe Racer Mag.
1949 Triumph Speedtwin 500 pre-unit Bobber
My love for the classic English bikes, probably stems from Dad, who owned a Triumph Tiger 100 when he was growing up. My two brothers and I, like Dad, spent hours as kids, kicking around ideas in the garage and tinkering with motor bikes. Dad’s career as a motor mechanic fostered our curiosity of pulling apart and rebuilding the bikes we owned for fun and competition. These bikes had to stand up to racing motor cross, and short circuit, and the occasional jumping through hoops of fire – Dad’s three boys being members of a display team.
Oddly, after happily spending most of my youth being occupied under a car or bike, this was not something I wanted to pursue in a career. Fast forward 30 years. Now owner of a software development company, 25 staff to lead, grown up kids, facing an old age crisis… and dealing with the recent passing of mum. This was 2013.
Initially, the purpose of this build was for a project to occupy Dad. Also, seemed like the perfect topic for phone conversation – Dad now residing in Queensland, and my residence in Sydney.
I’ve always had a passion for design, predominately minimal style. I’ve been able to express this through various aspects of my life, most heavily in the designing of software. One of the privileges enjoyed in software design, is the anticipation and expectation of future versions – allowing the architect to rework and build on the same piece, always improving and simplifying. Not entirely translatable into hardware! It does however underpin how I work and my approach to this build. I’m not afraid of numerous versions in order to achieve the desired outcome. I’m aware of my limitations and am excited by the thought of creating and materialising new ideas whilst collaborating with many skilled people.
I wanted the bike to be a balanced composition of design and mechanics. I think this requires attention to every inclusion to keep the standard consistent. Whilst stylistically I was aiming for a minimal look, I wanted to retain the Classic Triumph features – iconic engine and separate gearbox. I also wanted to use the original frame and keep the 6 volt wiring – a bit of a personal challenge utilising my electronics background. It had to be rideable.
Steve Hazelton, a well known collector of classic motor cycles, knows how to excite when selling bike bits. Juxtapose a picture of the desirable Triumph Kestral with a heap of scrappy shit, and you get two mates, a ute, and a heap of enthusiasm on the way to Goulburn to collect what was advertised as a 1949 Triumph Speedtwin 500 pre-unit frame, engine, gearbox, rear wheel and a box of stuff. I shipped this to Dad in Qld for a complete engine build.
Dad’s not generally praised for his contribution to style, but he is well respected for his mechanical expertise. We established early on that this would be a custom build, not a restore. Great when Dad was given a specific plan, but yeah not so great when dad had creative licence, my credit card and an ebay account. Dad rebuilt the engine and gearbox from the ground up, to the point that we could kick it over. This process took about 18 months, and involved several trips to dad’s workshop. Most of the parts were sourced easily, with the exception of the inner primary case which appears to be akin to rocking horse shit. A nice moment when all three of dad’s boys were present for the first kick over, the only false start from a minor timing issue that required a swap of the spark plug leads.
I had made a few core decisions. This bike was to be a hard tail bobber, girder front end, 21 inch front, and 19 inch rear. Everything else would evolve from here.
I found Spitfire Motor Cycles in California could supply a set of custom Harley girders. This presented a challenge with sizing reference to Harleys. It took a trip to Dad to chock up the bike, and the assistance of a work colleague with a pure maths degree, to work out the right length of the forks to suit the desired stance. Apparently 2 inches under stock is a legitimate measurement.
I imported the rims from Italy. Borrani supplied the 21inch WM2 front wheel, wrapped in an Avon Speedmaster Mk11, and the 19 inch WM3 rear, wrapped in the Safety Mileage Mk 11. Both rims were anodised black. Dad sourced a twin leading shoe front brake and both rims were laced with swagged stainless steel spokes.
I used a peanut tank to kick it over, but this didn’t thrill and was just a temporary inclusion.
With the engine and gearbox complete, I shipped the bike back to Sydney. Mike from Deus put me in touch with Steve O for the tank build. Initially, I had very specific ideas. Some of these would eventuate and others would change as the bike’s character began to develop and dictate the right choices. The split tank became the design feature that set the tone of the bike. I had three key ideas in mind – it needed to sit as low as possible to follow the line of the frame, taper in to a point to meet the seat, and leave a clean gap between the tanks to expose the engine.
The original concept was to mount the tank from the bottom, and tie the top of the tanks together with feature straps, in the same style as the external oil feeds – a nice design component of the engine. After having top straps designed and fabricated, It just looked all too busy, so I ended up fixing the tanks together by fabricating a stainless pin that is hidden under the top frame tube.
Rather than building a tank from scratch, I sourced a really big fat arse Harley tank, had it cut down, split in two, and sliced, so that it sat nicely above the engine.
Guards (sorry Fenders)
I had the front and rear guards handmade by Joe from Cooper Smithing Co. located in Washington State USA. Joe gave me the exact measurements he required, so he could make these to specs. We spoke about being minimal and the guard being thick enough and ribbed to eliminate unwanted brackets. Local, John Abbott (who incidentally happens to be my cousin and well known panel beater) fabricated the upper and lower mounting brackets.
From the outset, the seat didn’t seem like such a big deal, but in hindsight the seat can really make or break a bobber. I really wanted to use the Haifley Bros Bates seat, however,I was running into a number of mechanical and mounting issues, and although I persevered with this for some time, it ultimately wasn’t working with the flow of the bike. This was one of those moments, where I had to step back, and re-evaluate. After much frustration, I just went and bought a whole heap of seats to play around with shape and size. The bike hung together well with the Biltwell Slimline seat shape, so I pulled one apart and had a custom seat pan and bracket fabricated, which enabled the use of the original seat mounting point. The pan was upholstered in a single piece of fine grained leather, finished with fabricated brass hardware highlights to match the girder, and sits on a pair of 2.5” hairpin springs.
The Front End
I had the girder front end and the 21inch Borrani, but I couldn’t come up with a nice way of fixing the twin leading shoe to the girder. I went looking for a new front brake and came across a classic early seventies Triumph 8 inch conical. I worked out before I bought it that I could mount it nicely on the girder, but the issue was I had 36 spokes, and this hub was 40. So I ditched the first rim, sourced a 40 hole, and went through the processes again of anodising and respoking. Painful and expensive, but one of the elements that really suits the bike.
The original girder front end came with two modern billeted shocks that looked way too complicated. It dawned on me that a Harley is probably 2 or 3 times the weight of this bike, and I would need to lighten this up somehow. I replaced the two billeted shocks with a single Fox mountain bike shock that I got from the bicycle shop across the road from my office. Suffice to say a fair bit of re-engineering and fabrication was required to get this to work.
The girder is topped off with a set of Flanders 32” drag bars, mounted on Roland Sands risers, and Kungfu grips. The 1” throttle housing and hand controls are from Kustom Tech in Italy.
Now 2016 and nothing like a deadline to get things moving. With Throttle Roll at the back of my mind, I employed a mate, Brett Williams, to work on the final strip and rebuild.
Bretto is a hard core Harley guy from way back who has built heaps of bikes, and I really can’t put into words what a great job he did.
The Fuel, Carbs and Oil
Although Dad’s engine rebuild was awesome, I really liked the look of velocity stacks hanging out each side of the engine, so replaced the single 30 mm Amal carburettor with a pair of 26’s. I had some custom banjos made by Troy Fabrication in USA so that a single clear fuel line from each tank feeds each carby. Tip to self – fill both tanks at the same time.
The oil tank was one of the few things that wasn’t hard to work out. A standard 5” horizontal Moons Eyes from Factory Metal Works. Done!
After struggling with a set of original exhaust pipes Dad had sourced, I just assumed I’d have to get a set of custom pipes made. After a chance phone call with Bob from Classic All Parts who casually mentioned he had about four different exhausts available, I packed up the bike and headed off to see what would fit. Amazingly, he had a set of Australian made drag pipes with that classic Triumph curve, and slight kick at the end. Absolutely perfect, and sound just right.
The Lighting and Electronics
Batteryless would have been the easiest option, but for some reason I liked the idea of keeping it a 6 volt bike.
The battery is an AntiGravity 8 cell 6 volt lithium, tucked in behind the rear guard. The standard dynamo, re polarised, is hooked up to a Podtronics 6 volt negative earth regulator. A nice little custom electronics box is mounted up under the gearbox, and cloth wiring is used throughout.
A single brass four position rotary switch, off, kill, low beam, high beam, is the only switch on the bike, and is mounted on a simple 4” headlight fitted with an LED lamp.
The 6v LED tail/stop light is completely custom made and is housed inside a standard Amal velocity stack. The light is mounted to a custom license plate bracket which is illuminated by a single LED. It sounds pretty weird to use a velocity stack as a tail light, but the end result looks and works beautifully.
In keeping with the minimal theme, the speedo is a Garmin Edge 25. This is a tiny self-contained GPS based speedo that simply clips onto the handlebars when or if required.
Since purchase of the bike, colour had been a well debated conversation. Settling on a black frame, it was sent to Dutchy in Wollongong to be painted, after a disastrous powder coating experience.
For a long time, Petrol Blue was bandied around as the colour of choice for the tank and guards. And then I purchased the new Triumph Thruxton R in Silver Ice. Seemed to be a cool idea to match the old with the very new release. I got the colour matched and the tanks and rear guard painted by John McKenzie Smash Repairs.
I think the greatest challenge was not what to do, but what not to do. Trying to keep things consistent, and minimal, and not allowing one element to distract from another. Getting something to look simple, and just right, is incredibly difficult.
Overall the stance of the bike and the right flow – from the tank to the seat and following through to the guard – was the hardest thing to get right.
Then a couple of little themes, which hopefully you wouldn’t notice, which means it works. For example, the original rear engine mounts had been cheese-holed. So I followed this through on the rear brake stay. Again, trying to not over do things, some nice brass highlights – hand control adjustment, girder bolt covers, seat mount, the switch, custom choke plugs.
Aside from begging for an extra gear or two, and messing with my head with gear and brake levers flipped, it is a really fun ride. Whilst it is not a bike you’d ride every day, it is great pub hopper, and draws a crowd.
What started out as a little project to keep Dad occupied, really brought the family together in ways I really didn’t expect. Along the way, I hooked up and worked with a number of talented people.
Engine and initial build – Kevin Berger (Dad)
Strip and final rebuild – Brett Williams
Seat and general Fabrication – Tim and Joe – Impact Metal works
Tank Fabrication – Steve O
Guard – Joe from Cooper Smithing Co
Guard brackets and mounting – John Abbot
Wheels – Chivos
Sear Upholstery – Jeff Squires Trimming
Polisher and Chrome – Blu-Chrome
Tank and Guard paintwork – John McKenzie Smash Repairs
Frame paintwork – Dutchy’s
My partner in crime – Ren