Jake Snowdon's 250 Yamaha looks tidy, But look more closely and you see just how clever it is. it features dozens of handmade parts – And the engine has been on the dyno for over 20 hours…
I work as a mechanical engineer in Malmö, Sweden, having moved here just over four years ago for a girl. I’d been building bikes for a few years in Australia as a hobby so I set up my workshop and got on with customising bikes again. I spent a short spell working for Wrenchmonkees and Customs from Jamesville in Copenhagen, but like the girl, the bike building career didn't work out.
After a couple years as a product development engineer I decided I wanted to do something more than building bikes in my spare time, so I started a company designing and producing custom parts for specific motorcycle models. I started with the humble SR250 because it was the first bike I owned and customised. I love ’em. There is an ocean of SR250 customs out there but I had a clear picture of something special in my mind – something that would be classic, timeless, clean, simple, and appealing to all. I wanted to challenge myself to build something that was highly functional and legal; steering away from the typical ‘look cool quick’ custom tricks of getting rid of the blinkers, guards, or mirrors and staying away from the ‘clean triangle’ look. It’s not that I don’t like that stuff, I just thought it more challenging to design a bike that looked a little more complete and closer to factory-made.
I didn’t want any current fads. So Firestones, exhaust wrap, front-end swaps, mini-headlights, stupid thin ‘Brat’ seats, knobbly tyres on a street bike etc were not an option. Not that I don’t like some of those things, but I felt like these things come and go. Timelessness was my goal.
I wanted to design and develop special side covers that suited the new look. They were designed to attach to the stock mounting positions – in case I decided to produce these and people wanted to install them on their existing battery and airboxes. So the airbox side is a little bulkier than I would have liked. Anyway, the process was long and tough, but a lot of fun.
After sketching out many different concepts, I narrowed the design down to have one dynamic panel indent feature. Then I prototyped (3D printed) the design seven times to dial it in – tweaking the position, depth and transitions of the sweep each time, until I was satisfied. See how it lines up with the flow of the tank. I wanted something that didn't look too aggressive or out of place, something standard-looking.
I figured the bike should have no compromises in handling; suspension and tyre choice should be considered and frame chopping kept to a minimum. You might question the handling of a fat front tyre, but the bike turns in nicely because it has a slightly more aggressive rake now with the new ride heights – all worked out in CAD before settling on angles.
I also wanted to see what could be done in terms of engine performance, focusing mainly on bolt-on parts that are relatively easy to install. After more than 20 hours of dyno time – spread over two different test SRs and two dynos – the combination of ignition advance, optimised header design, special third wave harmonic intake stack, plus an oversized foam air filter, resulted in a 20% increase in both torque and power. And the torque is fat! It doesn't fall off until much later in the power curve compared to stock.
The extra gains made the clutch slip like crazy, so I installed 20% stronger than stock clutch springs, plus specially made spacers to raise the clutch plate pressure even more. I prototyped the header six times and tested two different designs – both with the same diameter tube but with different lengths. The chosen one had the best spread of power. I also developed and tested both a second wave and a fourth wave harmonic intake design. Neither were even close to performing as well as the third wave design.
These mods were the low hanging fruits; relatively easy to install, with big gains. After CAD simulations and hours of real world testing with temperature sensors rigged up to the head and oil system, both at the sump and after the oil filter, the finned valve inspection covers shed around 2-3 degrees of heat over the stock ones. The oil filter cover sheds around 3-5 degrees. It has an increase in surface area of 400% over stock and ups the oil capacity by 100ml.
I tried to use as many stock SR parts as possible – the ones that were cool or that I personally like, such as the stock headlight and rear mudguard. I didn't like the idea of kits, even if I kind of have developed a basic platform kit now.
I wanted the customer to feel that they have as much flexibility as possible, that they can still create their ‘own’ bike. I have developed parts that I would have liked to be available to me years ago – the hard ones to sort out yourself if you have limited tools and equipment. That's why most of my parts can be installed with simple hand tools.
The bike does not have mirrors as I tried four different styles and none suited. They all looked wrong. When it is on the road I guess I’ll just go with one of the sets, but in this case you could say that I cheated in the photos by removing them and therefore failed this part of my brief.
I can safely say that I could have built this bike in about 12 months if everything was custom ‘one off’ stuff, but it took two-and-a-half years. That is because every single special part on the bike has been sketched, developed, drawn up in 3D, prototyped using 3D printing (many, many times), laid out onto 2D technical drawings, production prototyped, test fitted, adjusted, tweaked and revised, then brought into production.
For me this is the precise difference between art and design – as I remember one of my Industrial Design tutors explaining to me years ago. This bike is a piece of design rather than a piece of art. It is not a ‘one off’ piece, even if it is, for now, ‘one of a kind’. Rather it is a template, repeatable for future builds and inspiration to other garage builders.
I feel like I got close to achieving my vision and design brief. I decided on a black, grey and silver scheme because it brings out the design features best. Colours can be loud and noisy distractions from purity. I also followed this scheme because it was so common for timeless bikes from the 30s, 40s and 50s such as Matchless, BSA and Vincent, for example. You will see the material finish and colour choice was very selective – with hints of chrome in very specific, chosen locations – not too much, just enough.
I don't know what you would call this style of custom. I have dubbed it a ‘clean standard’, others have called it a bobber, others a cafe-brat, others a cafe racer, some even resto-mod. Whatever, I hope you like it. I certainly had a lot of fun making it.