Dave Akhurst’s Greenfly: the LPG-powered custom motorcycle.


Dave Akhurst is a braver man than you or I. I feel confident in saying this because he rides around the countryside on the Greenfly - a heavily modified XT500 Yamaha that runs on Liquid Petroleum Gas (LPG) - and thus, if he happens to fall off, there’s a pressurised gas tank right there between his legs waiting to blow his bollocks off if it gets punctured.

The benefits of running vehicles on LPG are reasonably cheap running costs due to lower government taxes on LPG than unleaded petrol in most places, it has a high octane rating (108RON) and burns quite cleanly. On the flipside, you tend to get significantly less mileage per litre on a tank full of LPG than you would on petrol - and there’s the whole pressurised bollock-exploding gas cylinder thing to worry about as well.


The 500cc single still uses a kick-start, although Akhurst would put an electric leg on any production variant. It makes a lazy 30-odd horsepower and Akhurst figures he gets around 70mpg - compared to roughly 50mpg from a standard late 70s XT.

The rest of the bike is a very impressive demonstration of Akhurst’s metalworking skills. It features custom wheels, a single sided swingarm, a single sided front fork assembly, belt drive and custom pipes and bodywork all over - all presumably handmade by Akhurst in his well-appointed workshop, and all finished to what looks like an exceptionally high standard. He’s even fabricated his own gigantic touring pannier, which sits atop the subframe in place of the removable pillion seat.


The wheels in particular have an interesting feature - the outer rims appear to unbolt from the star-shaped hubs, and the Greenfly carries a spare rim (complete with tyre) in front of the engine, so switching wheels in the event of a puncture could literally be a five-minute roadside job. Good thinking there!


In Dave’s defence, the positioning of the tank would make it unlikely to rupture in many smaller crash scenarios - but in a proper, frame-twistin’ stack, I’d say you’d have enough to worry about without an additional explosion right under your mummy-daddy buttons. Very interesting prototype though!

Here’s a few other LPG motorcycle stories you might like to check out if gas is your thing:

- An Indian mechanic from Chitradurga gets 120km per kg of LPG

- LPG powered Goldwing

- LPG conversion kits for small bikes and scooters




Via MOTORRAD Online, where’s there’s plenty more photos.

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7 Responses to “Dave Akhurst’s Greenfly: the LPG-powered custom motorcycle.”

  1. kip Says:

    This is very really interesting concept. Great build with several interesting ideas.

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  7. Mad Mac Says:

    The one-piece combination side cases and top case is brilliant. The spare wheel also serves as case guards and highway pegs — pure genius. Flat tire, no problem. I love it. Back in the ’80s, I had an XT500. Good to see one still alive and kicking. Beautiful job.

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