BMW this week announced that its iconic GS will be fitted with a variable valve timing (VVT) engine from 2019 and, while the concept isn’t exactly new, it’s still quite rare on motorbikes.
The technology essentially means that an engine uses two sets of cam profiles, allowing the motor to be tuned for strong lowdown characteristics while switching to a higher lift/longer duration profile for more revs and more power. It’s been fairly commonplace on high end cars in recent years, but the complexity and cost of transferring the technology to smaller bike engines has meant that only Honda has really adopted VVT with any great gusto.
But with the Euro5 emissions regulations on the horizon and manufacturers having to find innovative new ways to make their engines cleaner, while retaining their performance, it won’t be a surprise to see more bikes equipped with VVT in coming years.
For now though we decided to have a think about what other VVT bikes are out there in the market. Here are the five we came up with…
Suzuki GSX-R1000R
Considering that it’s a breeding ground for new road bike technology, surprisingly VVT has been banned from MotoGP since 2016.
Actually, MotoGP regulations specifically forbid hydraulic or electronic VVT systems and where there’s a rule there’s a loophole. And this – the GSX-R1000R’s very clever system – is a result of getting around MotoGP regulations.
Developed on their GSX-RR racer and fitted to the eagerly anticipated 2017 GSX-R1000 road bike, the patented system uses a mechanical system that uses a cam phaser on the inlet camshaft. This phaser carries a number of small steel balls, which move outwards as the rpm increase. Because there are grooves in the phaser, the balls retard the valve timing by a few degrees to increase power higher up the rev range while boosting torque and throttle response at low revs.
Clever stuff!
Honda VFR800 VTEC
Think VVT, think Honda!
The Japanese giants started work on their VTEC (Variable Valve Timing & Lift Electronic Control System) system in the 1980s and the first bike to feature the tech was the Japanese market CBR400F of 1983, but VTEC became mainstream in 2002 with the introduction of the VFR800 VTEC.
At the time, the VTEC received a mixed reception. The pre-VTEC VFR was one of Honda’s most popular models at the time and some enthusiasts were not so keen on the distinctive step in the power delivery when the system activated.
The system Honda used on its cars is more complex than most, although the motorcycle engines used a simplified version of the technology. Called the VTEC-E, the first VFR800 only opened two of each cylinder’s four valves below 6800rpm, using oil pressure to activate a solenoid to open all four at the top end. The system helped reduce emissions and improve fuel economy, while allowing for a boost in peak power.
Honda revived the VFR800F in 2014, using a refined version of the 2002 technology.
Ducati Multistrada 1200 DVT
Ducati went variable in 2015, with a DVT (Desmodromic Valve Timing) version of its venerable Testastretta motor for the Multistrada 1200.
As with most VVT designs, the Multistrada boosted power (to 160bhp) and improved fuel consumption by around 8%.
The system uses a surprisingly simple little hydraulically operated actuator on the end of each camshaft. This continuously varies the position between the camshafts and crankshaft and works in conjunction with the sophisticated electronics to create a very smooth power delivery without the traditional ‘step’ associated with similar systems.
Clever, and no doubt destined to appear on future Ducati models too.
Kawasaki GTR1400
It took a bit of scratching the head to remember this one, but Kawasaki’s largely unsuccessful GTR1400 tourer featured a variable valve timing system back in 2008.
At the time, the GTR had plenty of interesting tech, including a keyless ignition system and, of course, variable valve timing.
The GTR’s ZZR1400-derived motor used technology developed by car company Mitsubishi Motors to advance the inlet camshaft by up to 24°. With continuous adjustment, the GTR’s power delivery was smoother than many VVT engines that had gone before – although the bike failed to capture the motorcycling public’s imagination and made very little impact in the sales charts during its 10 year production run.
Yamaha YZF-R15
Chances are our European readers have never heard of the YZF-R15, but if you’re in Asia, the R15 is pretty hot stuff.
Markets like Indonesia and Thailand are massive for the Japanese manufacturers and bikes like this sell in big numbers. It’s not dissimilar to the popular YZF-R125 we get over here, but it’s powered by a 19bhp, 155cc single cylinder engine… with variable valve actuation.
Known as the ‘v3’ (as it’s the third generation R15) the system switches the R15 from its bottom end profile to the top end one at 7400rpm. It allows the bike to make its peak power at 10,000rpm, while retaining decent torque low down. Reports suggest that performance is on a par with most 250s, while fuel consumption is in line with other 150cc bikes.
It costs the equivalent of £1800, showing that VVT technology could well be commonplace on bread and butter bikes in the not too distant future.
