Technical

TECHNICAL FEATURES ARCHIVE

The most recent technical features are listed below, or for a full list of the rest, click on TECHNICAL FEATURES ARCHIVE

Seat of the pants stuff

The science of sitting comfortably is harder than it looks

For a manufacturer, technical challenges aren't all cutting-edge electronics and active suspension. And it's easy to dismiss cruisers like Triumph's new Thunderbird Commander and Horizon LT as low-tech and simple to design. But they have their own challenges like, for example, making a comfy seat. It sounds easy: make it comfy. But there's more to it than that....

In the overlap of the gods

Making one engine fit many roles is all about getting the timing right...

What’s the similarity between Ducati’s 2009 1198 superbike, the Multistrada, Diavel and new 1200 Monster? Yes, they share versions of the 1198cc Testastretta engine. The versatile V-twin has gone from sportsbike to adventure bike to power cruiser to naked in just five years.

You’d think their disparate riding dynamics couldn’t be achieved with the same engine. So how does the 1198 Testastretta fit such different roles?....

Tough Torque

KTM’s 1290: why they call it PR ‘spin’

KTM test rider and ex-500cc GP racer Jeremy McWilliams says the new 1290 Super Duke is the torquiest bike he’s ridden. KTM claim it makes more at 2000rpm than the 990 Super Duke at peak (70 lb.ft). That’s a lot of big torque talk.

Torque is often wrongly thought of as a measure of engine performance at low rpm. Big V-twins have ‘lots of low-down torque’, and inline four sportsbikes ‘lots of top-end power’, as if the two are discrete and opposite. They are different, but not opposites...

Compounding: The Problem

Ever wondered why your rear tyre wears down in the middle but not at the sides? It’s safer that way...

At first glance there’s nothing in common between touring on a Triumph Tiger 800 XC and a 250bhp MotoGP prototype. But there is.

I recently had a 3000-mile ride on a Tiger. Its Bridgestone Battlewings were 4000 miles-old at the start and, as you’d expect, the rear squared-off as the ride went on. 7000 miles isn’t a bad total, and the bike maintained its steering and stability. But eventually it shimmied a bit over white-lines as it rolled across its squared-off centre. And with plenty of tread left on the edges, it seemed a waste of rubber to chuck it away.

So why don’t manufacturers make rear tyres harder in the middle where they wear the most?...

Fuelling about with maps

Selecting a power mode on your bike? The future’s already been mapped out. Literally.

Fitting a litre sportsbike with a castrating low power engine mode sounds like a bad idea, even if you call it ‘Rain’ mode. And few electronic aids are as contentious because engine modes are, technically, voluntary restrictions. Each is, broadly speaking, an overlay of instructions directing the ECU to manipulate and reduce engine performance.

But what actually happens when you push that button...?

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.

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.

Extra sensory perception: how our bikes know more than we do

Modern bikes are smarter than ever. But they can’t see into the future. Yet.
BMW’s HP4 is a clever bike. An array of more than 30 sensors stream info to its ECU, making our five (or six?) human channels of data acquisition seem inadequate. But we don’t have to reign in 190bhp… which is why bikes have brains too.
The BMW, along with Ducati’s Multistrada and Panigale, and Aprilia’s Caponord and RSV4 R APRC, is at the current summit of bike IQ. But most modern bikes have some of the following going on the moment you turn the key:
Electromagnetic pulses count spokes in ABS rings around both wheel hubs, measuring speeds and looking for differences. The ECU uses the info to activate its ABS system, and also feeds the data into a map of engine management, and traction and anti-wheelie control. It also delivers road speed to the clocks.

Yamaha Three-Cylinder Cross-Plane Concept

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Yamaha has intrigued the bike world with the unveiling of a prototype three-cylinder engine at Cologne, sparking some wild speculation by saying it comes with a cross-plane crankshaft.

Ducati Multistrada 2013 Skyhook technical

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There are two main technical advances on the 2013 Multistrada. One is a package of upgrades to the engine, but the second is the real headline: Ducati Skyhook Suspension, semi-active electronics have arrived in motorcycles!

BMW K1600GT torque comparison

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Considering BMW`s claim of huge torque figures at low revs for the new K1600GT (full riding review here) and the GTL, which has an identical engine and drive line, it`s something of a surprise to find the bike demands a downshift or two to accelerate sharply when overtaking.

How ABS works

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It`s still commonly thought that ABS works by comparing the speeds of the front and rear wheels, releasing brake pressure if these should differ significantly. This is wrong.

Ducati 1199 Panigale Engine

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Ducati`s 2012 Panigale 1199 is powered by the most radical engine seen in any production motorcycle.

Bosch ABS testing

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The adoption of ABS on bikes is years behind the car world. Across Europe only a third of bikes over 250cc is fitted with it, while one in 33 smaller two wheelers have ABS. Yet almost all new cars have it, so what`s going on?

BMW Semi-Active Suspension DDC

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BMW is the first company to announce semi-active suspension for motorcycles. The new system, called Dynamic Damping Control (DDC) will be appearing on 2012 models as the next logical step forward from the existing ESA II electrically adjustable suspension.

BMW K 1600 TFT display

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Yet another innovation on the BMW K 1600 machines is very obvious from the saddle - the TFT display screen. TFT stands for Thin Film Technology, and while it`s a form of liquid crystal display, it differs in an important aspect.

Désaxé engines

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Kawasaki`s 2011 ZX-10R Ninja is bristling with state-of-the-art and new technology, but like so many ideas, some can trace their roots back a very long way. The Ninja`s engine uses a désaxé layout, which means the centre line of the cylinders is offset, and rather than crossing through the centre line of the crank as on most engines, it passes 2mm in front of it, on the exhaust side.

BMW K 1600 Adaptive Headlight

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How do you get a headlight beam to stay level when a bike is leaning over? That`s what BMW has managed with its latest raft of world-leading technology on the K 1600 series.

Honda Dual Clutch Transmission

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Rather oddly, Honda stresses that the new Dual Clutch Transmission fitted to the VFR1200F is not an automatic transmission, but electronic manual transmission. Yet it patently is automatic!