Allen Millyard’s 8000cc, 500-bhp Motorcycle Special…
Engineer and custom bike builder Allen Millyard will go down as one of the greatest custom motorcycle builders of the past century, best known for his multi-cylinder specials whose engineering wizardry beggars belief. We’ve had the good fortune of viewing several of his builds in person at Alabama’s famed Barber Museum, which houses Millyard’s 1976 Kawasaki 850/5 two-stroke, 1974 Kawasaki 1600cc Kawasaki V8, and 2300cc V12 Kawasaki Zed.
Many of Millyard’s builds could be mistaken for factory bikes…until you take a look at their engines, which often boast twice as many cylinders as standard. That makes Millyard a unique builder in the custom world, and that’s just how he likes it.
“Even though I don’t class myself as a custom builder in the same way as the Bike Shed guys and the people who build Harleys, I definitely love what they do and understand completely why they do it. I’ve always tried to make my bikes look ‘factory’ as if they’ve been made by the original manufacturer – even though this often means a lot of extra work.” -Allen Millyard, MCN
However, Millyard has been known to come up with some radical customs as well — motorcycles that couldn’t be mistaken for factory machines…unless those factories were straight out of an alternate universe. One of those is his 5000cc “Flying Millyard” — a bike whose behemoth V-twin and antique style look like something from a steampunk film. But the bike is no show pony — it’s a one-kick bike (as Allen often demonstrates) that will cruise happily at B-road speed.
Surely that 5000cc V-twin is the biggest, baddest, most radical Millyard special of all, right? Nope. That honor goes to Millyard’s 8000cc, 500-bhp Viper V10-powered special.
It all started at the Goodwood Festival of Speed some 20 years ago, where Daimler Chrysler put their Viper V10-powered Dodge Tomahawk on track…in a rather underwhelming display that didn’t top 70 mph. As many of you might know, the Tomahawk was a non street-legal concept bike that came out in 2003, powered by a Viper V10.
Dodge officials made some ludicrous performance claims of a 400 mph top speed, which threw up red flags, especially when independent testing was never allowed. Ultimately, nine more Tomahawks were built by RM Motorsports (to whom Dodge outsourced the original concept’s fabrication) and sold through luxury retailer Neiman Marcus for $555,000 each.
Though this “rideable automotive sculpture” was a huge publicity success, keen-eyed engineers and motorcyclists saw past the buzz, apprehending that the 1500-lb four-wheeled behemoth was more sculpture than rideable. Allen’s son, Stephen, was one such sharp observer:
“When Stephen saw the Tomahawk, he said, ‘You could do better than that, Dad.’ When we got home, he found a Viper engine on eBay. I bid and next thing Stephen’s shouting, ‘Dad, you’ve got the engine!’”
And so Allen Millyard, a lone engineer working out of his single home garage, set out to build a V10-powered motorcycle of his own — one that could actually be ridden at the speeds an 8000cc 20-valve SRT10 engine made it capable of attaining.
Work began on the build in the summer of 2007, and Millyard had a rolling chassis by the end of the year. There’s no single frame here. Rather, the engine acts as the central stressed member, with a tubular steel subframe bolted to the front, a single-sided swingarm bolted to the gearbox, and an alloy rear subframe attached to the rear of the V10.
Of course, there were no forks robust enough to support the weight of the 630-kilogram (~1400-lb) weight of the bike, so Millyard had to get creative. He used 75mm JCB hydraulic rams as stanchions, with modified Vauxhall damper rods and Hagon springs. Meanwhile, K-Tech resprung a pair of Yamaha R1 shocks for the rear suspension.
Allen hand-built the headers, which were ceramic-coated, and the heatshields use NASA Space Shuttle tiles! The video below shows a demonstration of the tiles in action, as well as many other neat details of the build.
Millyard says he was going for a street cruiser look, not a sport bike, and the overall impression is of the rider sitting astride a giant muscle car engine — which, in effect, they are. In fact, the first time Millyard fired up the bike, it very nearly bucked him off, so the old cast-iron flywheel was quickly swapped for a lightweight aluminum unit. The bike was completed in 2009, and unlike the Tomahawk, it’s road-legal, passing inspection and receiving a UK SVA (Single Vehicle Approval) on its first attempt.
Just how fast is it? On one of the early test runs, test rider Bruce Dunn clocked 207.101 mph (333 kph) at the Bruntingthrope test track. Reportedly, the main limiting factor isn’t mechanical or aerodynamic — it’s the rider’s ability to hold onto the handlebars at such speeds, especially with no streamlining and an upright riding position.
Millyard himself has done over 200 mph on the bike, and in 2023, he and TV presenter Henry Cole captured a Guinness World Record for a pair riding tandem on a street-legal motorcycle when they hit 183.50 mph.
Millyard has his eye set on 250 mph, but in the meantime, he doesn’t just leave the Viper languishing in the garage. As of late 2022, Millyard had nearly 10,000 miles on the bike, including a spirited trip around the Isle of Man.
All told, Millyard only spent about a year building the bike between other projects, and he’s duly proud of what he accomplished:
“Really, I did it to beat the Americans at what they do best. They’ve had two attempts at building a Viper-engined bike (the Tomahawk and a one-off Boss Hoss version) and this is better than both.”
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Instagram: @allenmillyard
YouTube: @AllenMillyard
More Millyard Specials
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The Millyard Viper: 8000cc Viper V10 Custom Motorcycle - Allen Millyard’s 8000cc, 500-bhp Motorcycle Special… Engineer and custom bike builder Allen Millyard will go down as one of the greatest custom motorcycle builders of the past century, best known for his multi-cylinder specials […]
5000cc V-Twin! “The Flying Millyard” - No Replacement for Displacement… Allen Millyard is nothing short of a living legend, an engineer and custom bike builder best known for his mind-blowing multi-cylinder motorcycle specials that defy mechanical belief. The first time we […]
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What can anyone say? Pure mechanical genius!
Absolute legend and a gent.
Top man 👍
Love all the Millyard bikes. If there ever was a Nobel Peace Prize for motorcycle building, Allen would win by acclimation. His videos are an object lesson on imagination, patience, and craft. May he live forever.
Excellent article and photo work. My jaw now needs a return mechanism. The first video shows no CNC machinery, and the rough cuts of the extraordinarily thick parts are consistent with finishing on the manual machines shown. Simply magic. And such a soft spoken gentleman. Wizard!
For some (exceptional) people, nothing is impossible.
Fantastic
So happy to see British mechanical know how’s still up there, and a Gentleman to boot. BZ Mr Millyard.
I find myself thinking about the possibility of chopping off the front (or back? Or middle?) 6 cylinders to make a merely 3.2 litre V4. A lot lighter, making a much more wieldy. Ike. Probably.
Shouldn’t stall to bad.
Do forget about me?? 😔
You are so beautiful and very
Allan you are simply the best and even that will not cover how great a wizard you are so proud to view your bike creations