2 Wheel Drive Yamaha R1 (no not a trike, it is real 2wd) *With video* [Archive] - IMPORTATLANTA.COM - Automotive, Lifestyle, Offtopic, Forum, Blog, & Online Community

EJ25RUN

06-28-2009, 03:41 PM

Yes, i realize Yamaha ran a 2wd dirt bike in the 2007 Dakar rally but this a development that has been going on for some years to bring 2wd to sport bikes.

Most riders still say it is to awkward and the extra weight makes the bike slower and handle worse.

http://www.youtube.com/watch?v=neyqXj-txFA

http://2.bp.blogspot.com/_Mvhjidbvdzc/ScNDRwp5giI/AAAAAAAAN-8/UMkgR_tjjtA/s320/r1+jk.jpg

Fasterandfaster article.

Mark Gardiner, who writes a column called ‘Backmarker’ for RoadRacerX (and whose book, Riding Man, we had reviewed here), has written a very interesting piece on the use of 2WD on motorcycles. As many people might already know, Yamaha and Öhlins started working on the 2-Trac hydraulic 2WD system for bikes in the late-1990s, trying the 2WD thing on various off-road bikes, including the WR450. According to Gardiner, as many as 400 units of the 2WD Yamaha WR450 were even sold to customers by Yamaha France.

Yamaha later decided to abandon the 2WD program while Öhlins, who were at one point supposed to provide the 2WD technology to KTM (but never did...), also admit that the project is now dead. According to various reports, 2WD proved reasonably useful for the not-so-skilled riders, but did not provide a significant advantage in the case of skilled riders.

However, what’s really interesting is that Gardiner got to speak to Lars Jansson, the man who was in charge of research and development work on Yamaha’s 2WD YZF-R1 prototype, which was apparently being tested about 6-7 years ago. On the test R1, depending on grip and throttle position, the Öhlins 2-Trac system transferred up to 15% of the power to the front wheel. According to a statement released by Öhlins at that time was that the 2-Trac R1 was about five seconds faster [than a stock R1] around the Karlskroga test circuit in the wet.

According to what Jansson has now told Gardiner, there were issues with the 2WD system’s extra weight, power losses in the hydraulics and with high-speed manoeuvrability, with the bike not being too keen to change direction as quickly as a stock R1. Adding torque to the front wheel changed the bike’s behaviour dramatically, which expert riders couldn’t come to grips with right away.

Still, Jansson is convinced that had it been developed further, 2WD would have been a big safety feature for streetbikes. Of course, the whole idea of having 2WD on bikes not dead – we’d written about Christini’s mechanical (rather than hydraulic) AWD system here, and Gardiner says Steve Christini is already speaking to some bike manufacturers about developing AWD for streetbikes.

Gardiner, who’s writing a detailed article on 2WD on motorcycles for a magazine, says he can’t spill all the details right now, but he might in the near future. So the idea of using 2WD on sportsbikes/superbikes may not be dead after all! Stay tuned for more dope on this one…

MCN article

http://www.motorcyclenews.com/MCN/News/newsresults/Customs--modified-bikes/2009/May/may1809-secrets-of-ohlins-two-wheel-drive-r1/

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EJ25RUN

08-05-2009, 09:32 AM

http://www.motorcycle-usa.com/photogallerys/yamaha-r1-2wd-chart.jpg

MCN....

MCN has become the only publication in the world to ride Ohlins’ two-wheel-drive Yamaha R1. The bike which could have revolutionized riding – and may still – was long rumored, occasionally spotted but never ridden outside a select group of factory test riders, until now. We joined the Swedish firm on a two-day test at the remote Karlskoga track 200 miles north of Stockholm. The bike will now return to Ohlins’ ‘Area 51’ storage facility never to be ridden again, but not before we can reveal its astonishing real-world riding benefits, engineering genius and possible future.

MCN’s chief road tester Trevor Franklin rode the 2WD R1 to the limit in wet, dry and intermediate conditions at Sweden’s Karlskoga circuit. – Guy Proctor, Senior Editor MCN

Yamaha R1 Ohlins 2WD
The Ohlins' 2WD system has the potential to change modern sportbike performance.
Healthy regard for technical brilliance and safety – especially my own – has meant I’ve kept a keen eye on new ‘safety-based’ innovations in motorcycling. ABS was one such system. Fortunate to grow old with ABS’s intro and subsequent improvements, I was chuffed – after years of criticism and scorn – to see the final chapter ending with Honda’s brilliant sportbike-focused ABS. With this in mind we can forgive Ohlins for hiding its 2WD road bike project from cynical road testers like me. Until now…

First taste of 2WD wasn’t what I expected. Pushing the 2000, Ohlins road and track suspension-shod, Yamaha R1 around the paddock of Sweden’s Karlskoga circuit, it felt like the front brake pads were lightly sticking against the discs. The answer, from Ohlins engineer Leif Gustafsson, was honest and believable. New seals, bearings and fresh oil (synthetic engine oil) in the 2WD system meant it just needed the bike to be run to loosen everything off, rather like a new engine. With the bike warmed to operating temp while on front and rear paddock stands, the dragging front brake-feel disappeared.

First time out on a rainy and a very wet, unknown circuit is ‘ideal testing conditions’, said Gustafsson. Not in my mind it isn’t, particularly with the thought that this bike is the end result of a long, costly and angst-filled project – and I could end it on tarmac with the ominous sounds of splintering plastic and scraped alloys.

Through the paddock and onto the track entry point, the R1 feels no different to any R1 of its era – heavy, lots of body weight on the wrists, sat-in bike view from the low seat. Wobble through the end-of-straight hairpin and complete the first lap in the same slow, half-hearted way. It’s time to show willing.

Crack the throttle while upright and two things happen. Out of the corner of my right eye, the needle moves in the tell-tale bar-rated pressure gauge (for development purposes) cable-tied to the right mirror. There’s no sensation of anything out of the ordinary happening. Is it or isn’t working? Am I at the receiving end of an elaborate hoax? The answers come fast exiting the next turn.

Although not leaning like a racer looking for a podium, I consider the angle of lean to be enough, with a handful of throttle, to feel the rear squirm, slide briefly, or, at worst, send me arse over apex. Because of the slow speed (still thinking about being buggered by burly angry Swedish types if I drop the bike) two very unusual but noticeable things occur. First, there’s a slight sensation of the front wheel trying to pick itself upright. Secondly the bike as a whole appears to tighten up, become immediately stable with the loose, floaty feel from the headstock replaced with a more taut feel. At the same time the bike pulls without fuss.

Yamaha R1 Ohlins 2WD
Fitted to a Yamaha R1 test mule, the Ohlins-designed 2WD system allows a rider to pull away from the corners with more confidence in cracking open the throttle.
Try the same slow riding, small lean angle trick again and the same response. The slight front wheel twitch, for want of a better word, is like a signal to try harder. This ‘twitch’ fades to nothing as the pace picks up and dry lines appear. With a touch more circuit knowledge the R1 can now be used in anger. Brakes, throttle, suspension, tires… are all provoked. Strange but true, the bike makes me feel a lot more confident.

Driving and pulling

Kneeslider on the deck at about 50 mph, and a target rider in sight, on what looks to be intermediate tires, I start to lift the bike and wind the throttle on. There’s brief movement from the rear as the Pirelli tire struggles with the still damp surface, followed by nothing but clean drive – along with a stronger sensation of the bike being settled in the same way a bike feels being ridden at a steady 70 mph in a straight line.

Chasing down the rider in front leads to bravery. Too much. Braking far too late I peel in on the brakes and, where I should have my left knee over the kerbing, I’m about six feet off line. Running wide it looks like the R1 is going to go grass cutting as I exit too fast towards the outside of the track where it is sopping wet. As I start to steer the bike tighter I immediately get the gut-wrenching sensation the front is about to wash out. I nail the throttle in the hope the bike will straighten up and take to the grass for a softer fall. Then something magical happens: the bike smoothes out and literally drives (or pulls?) me around the outside of the track. Now what’s this all about? Has 2WD really saved my overweight carcass?

It’s the same story for the next two laps. Where the track is damp the bike instills enough confidence to open the throttle a lot more savagely than I would ever normally do. And more lean, way too much lean, does show the 2WD system isn’t infallible as the rear eventually breaks traction enough to cause a wide slide and out of seat experience. It’s more luck, than anything, the bike doesn’t go down.

With a dry line I push the bike to its peg-scraping limit. Furtive glances at the pressure gauge shows the needle lifting at nearly every corner. Especially through a second gear right-to-left flip-flop, where accelerating out over bumps the rear wheel struggled to put down the drive. But again the bike pulled smoothly out of the turn despite the engine revs rising and dropping.

Earlier and harder

Yamaha R1 Ohlins 2WD
"2WD lets you corner safe and hard. It will come.” Kenth Ohlin
Around the rest of the circuit the bike inspires enough confidence to open the throttle earlier and harder. And even though the rear end can be felt moving around, squirming and slipping in protest, the front of bike remains perfectly stable when it should be unsettled around the headstock. Bizarre. Again another big slice of throttle gets the rear to step out but it quickly recovers. Deliberately trying to slide the rear at the next corner causes a major slide and I panic shut the throttle. This time the buck and weave through the bike happens as I expected. I’m sure it wouldn’t have happened if the throttle had been open. Where the 2WD really excels is the right turn going onto the start-finish straight. The bike is really, really settled while banked and the throttle wound fully open.

Ok, as a cynic of anything that’s claimed to aid safety, I’m very, very impressed with the Ohlins 2WD system. As an aid to rider safety it is a perfectly executed plan. It surely won’t detract from our road riding pleasure and, as tested briefly by yours truly, will help in situations where you’d think the inevitable will happen. But like ABS and traction control, it is not going to save everyone in every situation – even these aids will see you on your arse if you ride outside their set parameters.

What we need to see now is 2WD on a thoroughly modern sports bike, where chassis dynamics of low weight, mass centralization, short wheelbase and race-like steering geometry, along with exceptional power-to-weight figures feature highly. Or failing that, on any popular category of motorcycle. Hopefully, we won’t be waiting for long.
Yamaha R1 Ohlins 2WD
Diagram the Ohlins 2WD system. The hydraulic 2WD units run off power transferred from the drive sprocket shaft.

How it works: Ohlins’ 2WD system revealed [annotations]

The genius of Ohlins’ sealed hydraulic 2WD system is the smooth way it applies self-regulated drive to the front wheel, sapping just 2.5bhp at 100mph and working in corners at all speeds, as well as when the rear wheel is spinning up.

1 Hydraulic pump
One of two identical hydraulic power units used in the 2WD system (the other being the motor in the front hub), this is driven by the drive sprocket shaft via two gears with a 2:1 ratio. The pump consists of seven small pistons with ball joints to allow the pump’s cylinder barrel to be inclined at 30-35°. As the pump spins, the pistons force synthetic engine oil through the narrow angle face to two flow passages, controlling feed and return flow. The pump is built to Ohlins’ specification not by Smith and Wesson, but legendary German manufacturer Bosch, and is capable of spinning to 14,500rpm.

2 Gas reservoir
Maintains the resting pressure within the system at 2-3 bar.
Yamaha R1 Ohlins 2WD
The Ohlins 2WD system is powered by hydraulic oil pumps.

3 Hydraulic motor
The same unit as the hydraulic pump, but reversed. When the rear wheel spins up, the gearbox sprocket driving the hydraulic pump spins faster, increasing the oil pressure in the system feeding this hydraulic motor. In practice the rear is always spinning up during riding – 0.5% more than the front at 50 mph increasing to 5% at 120 mph – as rubber can’t transmit drive without deforming. The same happens in corners as the bike rolls onto the tire’s shoulder: the diameter of the part of the rear tire touching the ground decreases more than does the front, requiring it to spin faster to match the same speed as the front. Rising oil pressure drives the hydraulic motor which connects to the front wheel.

4 Hub drive
The hydraulic motor drives the front wheel via a 14-tooth gear meshing with an internal gear ring of 75-teeth in the specially-made Marchesini wheel. Up to 33 hp can be delivered to the front wheel in this way. Valves in the motor release oil back into the return flow if pressure rises beyond a threshold, preventing excessive rear-wheel spin applying too much force to the front wheel. Tests demonstrated the front wheel was able to drive the bike on ice even with chain disconnected.

5 Oil cooler
High oil pressure and flow rate in a sportbike application means a small oil cooler is needed to maintain consistent performance of the synthetic engine oil used.

What can it do for average riders?

I trickle along pit lane at Karlskoga before nosing out onto the track, taking care to allow all the other riders to pass me before I hit the circuit. That’ll give me a few laps at least before I have to worry about getting in anyone’s way. I’m expecting to wobble round – not just because it’s an unfamiliar circuit with a mixture of wet and dry corners, there’s spots of rain on my visor and I’m not very good, but because I’m expecting the 2WD R1 to take time to learn. I’m convinced its behavior will be odd, it’ll take faith and experimentation to learn how to ride it the way it wants, and I’ll have to make the sort of allowances you normally do with development mules or project bikes.

Yamaha R1 Ohlins 2WD
Like most safety systems, like ABS and traction control, the 2WD system is not fool-proof but do deliver a safer ride.
But it’s not the case. The bike feels different – with a strange taut, alert feeling to the front wheel, almost as if it’s electrified – but there’s nothing to ‘ride around’ and it doesn’t demand a change in riding style. Leaning the bike at any speed makes power feed – in imperceptibly smooth increments – to the front wheel, and I’m grateful I don’t have to be spinning up the rear Garry McCoy-style to appreciate its 2WD-ness. The effect is simply to make the bike feel as if it’s doing more of the road-reading and corner-assessing for you. Instead of tipping the bike in on damp corners and feeling (in my case hoping) for grip before driving through and trying again a bit faster next time, it’s as if the front wheel has scouted out ahead already and is telegraphing the message back that everything’s okay – come on, gas it. My speed never reaches a level to draw Ohlins technicians, wonderingly, to the pit wall, but I get to my comfortable max quicker – much quicker – than I would with just rear wheel drive.

I hate riding in the damp, and I was dreading this ride when it came to it, but just a few laps in and I’ve stopped thinking about when and where I might crash, and started wondering where and how much I can make up. On the straight none of the R1’s power has been blunted, and I can gain ground there. In the corners I feel like I can hold the line I choose better and accelerate harder – which would be great if knew what the right line was. I’m lapping as fast as I want to, the tires feel like they’re concreted into each corner and I’m just beginning to feel hopeful for the obligatory cornering shot when I get blitzed, first by a KTM640, then an RS250 with Ohlins' technician Erica’s pigtails flailing, and soon after by an R6. It’s a timely shot of perspective: 2WD can’t make a superhero out of a snail, but it definitely encourages it to come out of its shell.

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