This is both the coolest and weirdest motorcycle/dirt bike we have ever seen. Constructed by the internationally known Aussie builder Ian Drysdale in 1990 it is an engineering experiment that pushes the boundaries of everything you think you know about motorcycles. As this was the only one ever built, it was not exactly a massive success, but when you look at it for the awesome, out of the box experiment that the machine represents, it becomes one of the neatest things we have ever laid eyes on and we have to thank Peter Dunn for the tip on its existence. Basically you are looking at a motorcycle where the engine has no direct link to the wheels and the handle bars have no direct link to the wheels. Seriously.
The idea here was the build the ultimate, unstoppable, go anywhere motorcycle. If you have ever seen an old Rokon two wheeled bike and what those things are capable of, you’ll appreciate what Drysdale was getting after here. He went totally into outer space on the mechanical end of things. The 250cc two stroke engine does nothing but spin a hydraulic pump. That pump makes over 4,000psi of pressure and uses that pressure to turn some sort of hydraulic motor in each of hubs to make the bike move. Vary the pressure and you vary the speed. For turning, the handlebars are actually attached to a hydraulic master cylinder that moves fluid that then actuates rams to turn the wheels. We told you that this thing was completely bizarre. We’re not sure if the intention was to build just one of these or if the intention was to try and market the idea but outside of the obvious there were other issues, primarily the braking which was also done hydraulically and apparently would push the seals out when used aggressively. Other stuff? We’re guessing that because the wheels are hydraulically driven, they do no freewheel when the engine is not running. That’s kind of an issue.
We’d not classify the Drysdale Dryvtech hydraulic motorcycle as a failure but as a far out experiment about what is possible when someone is allowed to put all of their ideas into practice and actually has the skills to see it through. We’d enjoy owning this machine even just to make people stare at it and have them try to tell us how it works. That would be great fun at parties.
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No wonder only one of these was ever made – only a total lunatic would ride a bike where the steering was not directly connected to the front wheel!
Bimota built a few like that too. Must all be lunatics.
I would imagine the valving for the wheel motors would use a motor spool that would allow the oil to still circulate the motors in the neutral position and save the rider from going over the hangers if they let off the throttle. Cool bit of gear
http://www.ebay.com.au/itm/DRYSDALE-Dryvteck-2-wheel-steer-2-wheel-drive-/191431097508?clk_rvr_id=744561540219&nma=true&si=zfMnJBbhybos%252BEaOvq8T077100s%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557