2 wheel drive yamaha?

5 replies to this topic
  • AK-thumper

Posted December 12, 2001 - 11:29 AM


MCN (www.motorcyclenews.com) posted some pics of a yamaha/ohlins developed 2 wheel drive R1. They say it followed the development of a dirt model. Anybody know where info on the dirt prototype can be found? Sounds cool to me, but the system looks a little heavy for a dirtbike.

  • Guy

Posted December 12, 2001 - 12:37 PM


Had a real good look at this at the Bike show last year....the system is NOT that heavy, It has been developed in conjunction with Ohlins who did the Hydraulic pump and rotor bits, Basicaly there is an Extra front Sprocket which drives a pump which via braided lines drives the front Hub, so it is speed dependent NOT revs, Yamaha Belgardo(Italy) who developed it also did a TT600 (I think) which they entered into the Paris Dakar Raid with some success.
The only bit which does not LOOK nice is the front hub which looks like it has come from a time about 20 yrs ago before disc brakes
I could be wrong but I believe that they also have used it on a 400/426 again with some success!
It is called a "Twin Trac" if I find a web address I will post it here! :)

  • Guy

Posted December 12, 2001 - 12:45 PM


Two wheel drive!
Have a look at this! Click on the RED enduro at the top of the page and there is more inc pics of the 426

[ December 12, 2001: Message edited by: Guy ]

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  • joao_pedro

Posted December 12, 2001 - 12:52 PM


dear fellows,
I got quite a lot of pictures of an 2001 wr 426 2X2 from a swedish site ! Don't you understand a single word of swedish? neither do I! no problem! The page is www.mcpoolen.se, and once in it just dig and search what you want or... just message me privately (because I check it regularly!) leave your e-mail and I'll be glad to sent them to you!
bnesides that I've found images on an american site of a turbo charged XR 650...weird, don't you think?
my best regards

  • Ron_in_SoCal

Posted December 12, 2001 - 01:40 PM


This is from an Ohlins newsletter dated February, 2000:
Posted Image
Since 1992 Öhlins, together with Yamaha, have been developing a 2-wheel drive system for motorcycles. Prototypes have been raced with success in Gotland Grand National, Sardinia and in Dubai. In March some leading motorcycle magazines were invited to a press demonstration in Bibione, Italy. The articles that followed all praised the good performance of the system.

The Ohlins-Yamaha 2WD system is the brainchild of Yamaha R&D Manager Bob Trigg and Ohlins Future R&D Manager Lars Jansson. Over the years Lars and Leif Gustavsson have developed the system on 10 different motorcycle applications.

Two wheel drive systems (2WD) are not new to motorcycles. In the past several systems have been presented and tested. What is common for most of them is a mechanical transmission to the front wheel, necessitating a substantial redesign of the front end and suspension. Most of the systems have only a primatively regulated torque distribution between front and rear wheel.

The new Öhlins 2WD system is based on hydrostatic components. The gearbox drives a pump, at a speed corresponding to the rear wheel speed, which feeds oil through flexible hoses to the front wheel. In the front wheel hub there is a hydraulic motor driving the wheel through a gear.
The gear ratios to the pump and the motor are chosen so, that in relation to road speed, the pump and the hydraulic motor turn with the same rpm. When the rider is coasting there is no power delivered to the front wheel, but when he opens the throttle and the rear wheel starts to rotate faster, oil pressure is built up in the system transferring power to the front wheel.

The Öhlins 2WD system is selfregulating, which means that the front wheel can never spin faster than the rear wheel and that the power transferred to the front wheel is never greater than what the wheel can use for traction. In short, throttle position and road condition determine how much power at a given circumstance will be transferred to the front wheel. The function resembles what you get with viscous couplings used in automobile 4WD transmissions.

By using flexible hoses and the fact that less than 10 % of the engine power can be utilised by the front wheel and thus will be transferred, a standard type of telescopic front suspension can be used. Also, the
hoses between the pump and the motor in the front wheel are arranged in a way so that no reaction forces are felt in the handlebars.

The system has been under development since 1992 and has been tried on different types of motorcycles and extensively tested under various climate conditions, from fine sand in hot summer to icy conditions in full Swedish winter.

With the Öhlins 2WD system the bike is easier to handle in terrain, especially on soft ground and in steep uphill sections. In sand and on slippery, icy conditions the Öhlins 2WD is the system to beat!

  • linmag

Posted December 17, 2001 - 10:20 PM


Just thought I should add some info about an turbo charged XR650. PG Lundmark is a swedish driver who competes in Paris-Dakar (and I think he did one Baja2000 event also) and he has a XR650 with turbo. This is a swedish site with some info about the bike:
For those of you who does not understand swedish I can translate some information:
Completly stock it had 41 hp (at the rear wheel) and with the HRC kit 49 hp. With the turbo it has 70 hp!! Nice bike :)

/ Magnus


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