Allen Millyard’s Second, More Powerful Six-Cylinder Zed…
In our estimation, Allen Millyard is nothing short of a motorcycling treasure. While the retired nuclear engineer and motorcycle mad scientist hails from England, his creations have dropped jaws all over the world. Though outsized specials like his 5000cc V-twin “Flying Millyard” and Viper V10 bike might get the most attention in wider motoring circles, we’re partial to Millyard’s Kawasaki builds that look like stock restorations…until you notice the extra cylinders wedged into their frames.
Given the complexity of adding cylinders to existing engines, it’s incredible that Millyard doesn’t use CAD or any sophisticated modeling techniques to build machines like his Kawasaki “Z2300” V12 or Kawasaki “Z1600” V8. No, the man cuts crankcases with a hacksaw, assembles rollers on his kitchen floor, and preheats aluminum parts on his barbecue for welding!
Millyard’s videos are also a treat, as he’s very humble in explaining how he works through the various challenges of his builds. He doesn’t have a high-dollar workshop with the latest gear, but a fairly austere shed-shop with a lathe, dressing files, his trusty hacksaw, and few tools born less than half a century ago.
Though many of Millyard’s early specials were two-strokes such as his five-cylinder Kawasaki KH500, he also has an affinity for the mighty Z1. In fact, during the pandemic, he began work on not one but two Kawasaki Z1 six-cylinder specials. We featured his blue “Super Six” just last month.
Now we’re excited to showcase his second Z1 Super Six build. While the blue bike was 1396cc, this one displaces 1522cc, as Millyard used the slightly larger sleeves from the later 1015cc Z1 engines.
Millyard has said he especially likes the inline six-cylinder arrangement, which matches the layout of bikes such as the Honda CBX, Benelli Sei, and Kawasaki’s own water-cooled, shaft-drive Z1300. Why? Well, unlike his Kawasaki Z1 V8, the Super Sixes appear unmodified from the side.
It’s only when you’re at the right angle to notice the width of the engine and count the number of cylinders that you realize some very serious surgery has been accomplished on the bike.
As most of you know, the original Kawasaki Z1 was no slouch. It stunned the motorcycling world as the most powerful four-cylinder four-stroke ever to come out of Japan.
“An instant hit, the Z1 was named the MCN (Motorcycle News) Machine of the Year for four consecutive years from 1973 to 1976. As if that wasn’t enough, the Z1 was the world’s fastest motorcycle in 1973, surpassing a record that had stood since 1948 thanks to its 130 mph top speed.” –Old Bike Barn
At the time, Kawasaki and Honda were in an arms race for superbiking supremacy that would last for decades. In fact, the original Kawasaki Z1 “New York Steak” prototype was only 750cc, but Honda stole their thunder with the introduction of the CB750.So the Z1 was postponed until its displacement could be increased. When the Z1 finally appeared in 1972, it was 903cc and blew the CB750 out of the water.
Honda was the first Japanese manufacturer to introduce a six-cylinder superbike in the form of the CBX1000. While Kawasaki did release the (K)Z1300 soon thereafter, it was liquid-cooled, shaft-drive, and more of a Goldwing-size tourer than an old-school superbike.
Millyard’s “Super Six” gives us a window into an alternative history, where we can see what an air-cooled six-cylinder Zed might have looked like. In fact, he’s done such a good job the bike looks like some kind of in-house concept or period prototype built by Kawasaki’s own engineers.
As with the first Super Six, two additional cylinders were added to the center of the new engine, not the outside. Millyard hacksawed one engine in half, then added cylinders two and three from a second engine. The firing order is 1-4-2-6-3-5.
“I use a 120-degree crank so the middle cylinders are offset by 120, then the next two and then the outermost two. So you end up with a standard firing order.” -Millyard, MCN
Below are more of Millyard’s information videos about the Super Six builds — we highly recommend them. And make sure to check out more Millyard specials below.
Super Six Playlist
This is the first video in Millyard’s 19-video playlist dedicated to the Super Six builds. You can hit the emblem in the top right corner to skip ahead to the other videos. Millyard is a treat to watch — enjoy!
Follow the Builder
Instagram: @allenmillyard
YouTube: @AllenMillyard
More Millyard Specials
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Good looking bike.
I bought a motorcycle for my retirement a couple of years ago, 2002 Kawasaki 1200ZRX, not sure what I was thinking…one bike leads to another, I now have 12, various makes and years. And rebuilding a South Bend Lathe, and bought a little ‘tabletop’ milling machine. After watching Allen’s videos I felt I had to try making something…..