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Playing the frame game

Frames have got uglier and cheaper, but they’re straighter than ever. Suspension, on the other hand...

Last week’s Techwatch talked about how current production engines have close tolerances and matched components, and how automated mass-production reduces variability. If a modern engine makes 100bhp today, in 12 months’ time it’s likely the same model will also make 100bhp (although early BMW S1000RRs were an exception – bikes varied by up to 15bhp, and no-one knows why....

Putting up with intolerance

Sometimes the worse something fits, the better it works...

It’s long been a biking myth that in Japanese engine assembly plants, female workers are preferred to males for some jobs on the production line because they have smaller hands and greater dexterity. Having spent time at Suzuki’s vast Takatsuka Engine Plant in Hamamatsu, I can safely put that one to rest; it’s not true. They have plenty of both on the production lines.

But while I was there I saw something else intriguing:...

Swingarms and (bumpy) roundabouts

Ducati’s Panigale 1199 has a single-sided swingarm. The new 899 has a double sided swingarm. Now that’s a good idea...

It’s intuitive to grip a wheel at the end of each axle to give yourself maximum control of stability and alignment (or, if we’re talking about front wheels, steering). It’s certainly easier – it’s more effort to play wheelbarrows if you only using one arm to hold the barrow wheel. But it also looks cool if you wave with your free hand.

And so it is with swingarms:...

Variable Rates Of Interest

Variable valve timing: meet the engine technology that just won’t go away

In the list of pointless engine gimmicks, you’d surely put variable valve timing at number one. Only three production bikes have automatic VVT: Honda’s VFR800 VTEC (crude, two-stage system), Kawasaki’s 1400GTR (more sophisticated but barely noticeable) and, between 1991 and 1998, Suzuki’s Japan-only R-version 250 and 400 Bandits (crude and unnoticeable). And all of them gimmicks.

So what is VVT, and why do we keep hearing about it?...

Fins ain’t what they used to be

Why air-cooled bikes are having a water-cooler moment

In the news of their 2014 Touring range upgrades, Harley-Davidson smuggled a phrase rarely associated with the Milwaukee ironmongers (VRods aside): liquid-cooling. Before purists protest, Harley limit the ‘Twin-Cooled’ engines to four top-end models: the Ultra Limited, Electra Glide, Ultra Classic and Tri Glide trike. Which isn’t even a bike. But then it’s not really liquid-cooling either.

It’s fair to say the 45° V-twin has never enjoyed a reputation for cutting-edge tech; Harley are reputed to employ more designers than engineers.

But it’s also unfair to say. Designing a Harley engine might not be as challenging as building a 250bhp MotoGP engine that does 26 laps on 21 litres of fuel. But making an air-cooled motor sound and feel true to the Harley archetype yet meet stringent noise and emissions regulations is a challenge nonetheless.

My BikeSafe adventure

'ello 'ello 'ello'ello 'ello 'elloIt’s Friday night and my nerves are starting to show. I find it hard to eat my dinner. Tomorrow I’ll be off doing my first solo ride, further than my local Tesco shop! Not entirely true as I have had the Monster for a week and I have gone off by myself enjoying the Cotswolds. But tomorrow is different. I am riding down the motorway to taking a BikeSafe course in Leicestershire. I am excellent at envisaging beforehand all the things that could possibly go wrong. Forgetting to put fuel in the bike, making silly riding mistakes or not keeping up with the rest of the group. Well, I left nice and early, with a rucksack full of things girlies need and a big heavy Canon camera. The weather was gorgeous; sunny blue sky and a promise of some heavy baking in my leathers for the afternoon. I love Saturday early morning riding. Not a soul on the motorway, so I can do what I like. Cruise down the road at 50 to get used to motorway riding, which I have not done since riding to Silverstone last year? I pick up speed and notice 60 is the same as 50, only a bit faster (obviously). Looking in the mirror is funny, as everything behind you shakes up and down. 70 feels fine too and I let the road take me to Leicester.

My Ducati Monster 696.....for a week

Picking up my Monster from Ducati UK HQPicking up my Monster from Ducati UK HQI had a dream…. Hard to put on paper what it was, but it was very clear to me. I was riding a bike, and I felt comfortable. On waking I still felt at ease. At nine o’clock I would be picked up by Jonathan on his Honda. The sun was shining but the weather has been so changeable over the last few days it was a false security. I found it hard to decide to go for warmth and being dry or using my leathers. I am tough and mean, I thought, I can handle a bit of discomfort. After a delicious large coffee we set off and rode down the M40. The weather changed then and it became overcast and I was wondering of the rest of the day I would suffer for being silly and not going for wet weather clothing. It grew colder and the rain came down. I was perched high up, and there was no getting away from the wind and rain. It had been a long time being pillion and all the feelings of the past came flooding back. I closed my eyes and remembered.

Reading between the centrelines

Why the désaxé layout has become the latest fashion in engine design

Question: what has Yamaha’s new MT-09 inline triple got in common with their 2010 YZF450F motocross single, Honda’s MSX125 monkey bike and CBR250R, Kawasaki’s ZX-10R, Triumph’s Tiger 800, 1200 Explorer and Trophy, the Horex VR6, a 1979 Hesketh V-twin, a 1932 Ford V8 and an eighteenth century steam engine?
Answer: they all use the désaxé principle, in which the vertical centreline of the crankshaft is offset to the centreline of the pistons (désaxé is French for off-centre).
To picture it, imagine a side-on engine cut in half. Draw a line from the centre of the crankshaft up through the cylinders. On most bike engines with the piston at top dead centre, the line intersects the con rod and through the middle of the piston.
In a désaxé engine the crankshaft is set back a few mm (or cylinders forwards) so the line from the crankshaft no longer passes through the centre of the piston but to the rear of it.

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