Bright Sparks

Published: 13 November 2015

Mugen Shinden’s TT Zero-winner is a serious electric power pioneer – but is it really the future?

rom silence to 100% torque in one neck-straining second, the Mugen Shinden accelerates out of Motegi’s pit lane like a Bullet Train.

With the ride-by-wire throttle tube jammed against the stop, the wind noise intensifies and the roar of sticky Dunlop race tyres, scrubbing over perfectly groomed Japanese tarmac, gets increasingly louder.

As the first corner approaches a squeeze of the front brake lever invites the six-piston Nissins to hiss like angry snakes and we scrub-off speed in an instant.

It’s a cacophony of noise, from the brakes to the tyres, the suspension and windblast – everything, except the engine. But listen carefully and you can hear the faint whine from the 148bhp electric motor. With no petrol engine shouting in your ears and no clutch or gears to worry about, it’s surreal to be going this quick around a racetrack.

The Shinden is special. It’s a money-no-object racing machine, built with the same painstaking precision as a Repsol RC213V MotoGP bike to win an electric TT and make the world sit up and take notice.

With its carbon-fibre beam frame, swingarm and bodywork, magnesium wheels and engine cases, factory-spec Showa suspension and Nissin brakes, it’s a work of art. Think of it as a MotoGP bike with an electric motor.

This summer the Mugen Shinden scored a win in the one-lap TT Zero race in the hands of living legend John McGuinness, with equally handy team-mate Bruce Anstey coming home a close second. 

But it’s taken four years for Mugen to achieve such electrifying dominance at the Isle of Man. When the Shinden first turned up in 2012 (it’s never raced anywhere other than the Mountain Course), complete with a huge team of serious-looking, Japanese Mugen technicians, it didn’t have the impressive performance it has now. Back then it weighed a hefty 270kg, produced just 121bhp and went 130mph flat-out.

Back in 2012 the Shinden was good enough to propel new Mugen rider McGuinness to second place in the TT Zero race, with a 102.21mph standing-start lap. He finished second behind Michael Rutter, who also won the year before and after on his Motoczysz. The Motoczysz also won the first ever TT Zero in 2010, in the hands of American Mark Miller.

Ever since that first year the Mugen engineers have worked tirelessly to increase power, shave weight and improve handling. Time in the wind tunnel has ensured the Shinden slips through the fresh Manx air faster, too. Last year Bruce Anstey was also drafted into the squad to partner McGuinness, which helped speed-up development.

In just four years the Shinden has evolved to an incredible level. The 2015 Shinden Yon (Japanese for ‘four’) is still weighty and busts the scales at 250kg, but it now has 148bhp, tops out at 164mph along the TT’s fastest straights and has guided McGuinness to a race-winning 119.28mph lap.

Unbelievably, this electric bike is faster than the first flying lap of the best TT Lightweight bikes and sidecars. It’s still a way off the best 600s and 1000s, but it’s getting there.

It’s now a cut above its electric rivals and the closest competition this year was the Victory (a rebadged Brammo), which finished third and fourth with Lee Johnston and Guy Martin (with a 111.62mph and 109.71mph lap, respectively) aboard.

But let’s not get too giddy with the Mugen’s rapid ascent to the top. Although the electric motor has lots of power, seamless torque and a wonderful throttle response, it still has a way to go before it can compete with the humble petrol engine. And that’s all down to the limitations of the battery.

Wedged between the sculpted carbon-fibre frame rails where a conventional engine would normally sit, the lithium battery pack is huge and accounts for the bulk of the Shinden’s weight. Although battery technology is improving all the time, it still has minimal range (a lap of the TT), takes a five hours to juice-up, and degrades slightly every time it’s recharged. It’s also made with more exotic, limited-supply materials than a good old aluminium and steel petrol engine.

And of course, the Shinden might float zero emissions standing next to it, but life’s a bit smoggier next to the fossil-fuelled power station that produces the power in the first place.

An even bigger problem is our perception of a battery bike. Most bikers hate the idea of not having the noise, smell, vibration or soul of a petrol-powered engine. But ask anyone who’s actually ridden a battery bike and it’s a different story. An electric motor actually has a character of its own and is as individual as an inline-four,  single, V-twin, V4, parallel-twin, triple or boxer engine.

And here we are at Motegi circuit, on a warm, Japanese autumn morning, about to ride both McGuinness’ and Anstey’s Shindens.

The Mugen looks just like a normal racing machine, but there are a few clues to the strange power source that lies within: the red emergency stop button on the tail unit and the absence of a gear and clutch lever. The lever on the left bar is actually for the rear brake, like a scooter, or pushbike.

Out on track the Shinden doesn’t take any thought to ride fast and acts more like the world’s fastest twist-and-go. There’s an ocean of linear torque at your right wrist, delivered smoothly with the kind of flawless on/off throttle response we all lust after from an engine.

Both McGuinness’ and Anstey’s Shindens feel more or less the same to ride, but the main difference between them are the riding positions. Bruce’s is narrow-barred, high-pegged and cramped, like a pure race machine while John’s is more spacious with a taller, flatter, grippier seat.

Acceleration is on a par with a racy 600 or a road-going GSX-R750, even on its ultra-tall TT gearing, and the only thing stopping it from wheelying or shimmying in your hands under hard acceleration is the weight of the battery pack up front.

There’s no time wasted clicking through gears, just pin the throttle to the stop and the Shinden fires relentlessly from corner to corner. It has enough power to make a not-quite-up-to-temperature rear Dunlop shimmy and squirm for the first few bends.

Off the throttle there’s just the right amount of engine braking to help you into the corners without locking the rear wheel. And of course, every time you back off the power the motor is regenerating to help bolster battery life.

That big lithium power unit gets hot under hard load, so the Shinden reduces its own power automatically to regulate battery temperature. There are also two software maps to choose from. Mugen tell their riders to switch to the lower-power Map 1 for places where the battery struggles, like the uphill exit to the Gooseneck.

The Shinden weighs the same as a fully fuelled tourer, but it hides its bulk well. It’s nicely balanced, stable at full lean and agile flicking from side to side. With its factory Showa forks you can hammer the brakes again and again and this quarter-ton bike will stop on a Yen, time and time again with no fade.

Being so heavy, the Mugen lacks some of the rear tyre-squirming, front-wheel-lifting drama you get from a lithe and powerful superbike, but I still came back into the pits with a sweat-on, a big smile on my face and a new-found admiration for electric power. The best compliment you can give it is that it feels and acts like a normal motorcycle, albeit a very fast, TT-winning one.

Are electric bikes the future? Well, let’s say it’s still work in progress. Once those batteries get smaller, lighter, faster-charging and longer-lasting, electric bikes may finally be a viable alternative to petrol power.

So next year when McGuinness and Anstey line up on Glencrutchery Road, surrounded by a swarm of Japanese in white overalls, you might want to sit up and take notice.


 

How it works
It’s pretty simple really: the Shinden’s oil-cooled, three-phase, brushless electric motor draws power from its huge lithium battery via an inverter, which turns DC battery power into AC.
The oil-cooled electric motor itself has just one moving part: an electro-magnetic rotor that spins when a current is passed through it. Internal gearing reduces the final drive ratio.

Emergency stop button
Required for racing, this big red button on the tail unit isolates the power in an emergency. Just think: a silent, seemingly lifeless electric bike lying on its side in the gravel will still make 100% torque when you accidentally tweak the throttle while picking it up…

Carbon Chassis
With the batteries being so heavy Mugen have compensated by making the rest of the bike as light as possible. So, the twin spar frame and Fireblade-style swingarm are made from carbon-fibre, as is the wind tunnel-developed fairing, ‘tank’ cover seat unit and mudguard.

No gears, clutch and a funny back brake
With so much instant torque and a smooth spread of power, there’s no need for gears or a clutch. You just twist, go, and hang on for dear life. The rear brake is operated via a lever where the clutch lever is usually found.

How to stop a quarter of a ton
The six-piston Nissin monobloc radial calipers, master cylinder and twin 320mm discs are man enough to slow down a flying 250kg TT bike hundreds of times over a 37.7-mile lap without fading. It’s a genuinely impressive system.

Exotic components and sticky rubber
Special 48mm Showa fork has pressurised gas damping in the left leg and air instead of a spring in the right to save weight. Rear suspension has a fully adjustable Showa single shock. Marchesini magnesium rims are shod with sticky Dunlop slicks at the TT.

Lithium battery pack
The Hitachi Maxell lithium battery pack is encased in a carbon-fibre shell, with the joints and inside surfaces made from Kevlar. It takes five hours to fully charge the battery and easily lasts a lap of the TT at full power. The battery regenerates when the rider comes off the throttle and the bike is coasting.

AC/DC
An inverter, which converts the direct current (DC) power from the battery into alternating current (AC) for the motor, is fitted beneath the battery case, where the sump normally is on a conventional petrol motorcycle. As an added safety measure, it’s fitted with a breaker box to shut down the system in an emergency.

Electric power
Built in Mugen’s Tokyo factory, the oil-cooled, three-phase brushless motor’s cases are milled from a solid billet of magnesium for lightness and strength – a hugely involved and eye-wateringly expensive process. The motor is mounted low in the chassis, right behind the battery case.

Specification

Motor Oil-cooled 3-phase brushless electric motor.
Battery 370+ volt Li-ion battery
Power 148bhp
Torque 162ftlb
Kerb weight 250kg
Fuel capacity N/a
Seat height 790mm
Frame Twin spar carbon
On sale Factory racer only


 

Photos: Takuro Nagami