The Quail Gathering is the motorcycle equivalent of the Pebble Beach Concours d’Elegance: a world-class display of rarified exotica and immaculate restorations, plus a few jaw-dropping customs to spice up the mix.
To win an award at The Quail is no easy achievement. But this year, Niki Smart’s incredible Honda XL500-based special won not one, but two trophies: the Custom/Modified category, plus the ‘Design and Style’ award presented by Arch Motorcycles.
Niki is well known in the automobile world: he’s a British car designer now working in the USA. He first hit the headlines as the lead designer on the Ariel Atom sportscar, and followed that up with concept cars for Cadillac.
Most recently, he was a design manager for General Motors, working with the Advanced Design team in Los Angeles.
Niki’s bike, built around the engine of a 1981 XL500, was not your typical after-hours project—it took over a decade to finish and involved an army of specialists.
“There’s a long list of people who helped me a little, and a few people who helped me a lot,” says Niki.
Inspiration came from images of boardtrack racers that Niki saw at an exhibition. “I had never seen anything like the near-50 degree banking of the American board tracks.”
“The beautiful bikes of that era were legitimate 100mph machines,” Niki enthuses. “For me, the tall skinny wheels and tires balanced nicely with the pure open lines of the frame and engine.”
A second source of inspiration came from experimental European racers from the second half of the 20th century. “Before the telescopic fork took over, there were lots of interesting proportions thanks to unique front ends.”
Niki decided to use Hossack-style forks, and settled on the Honda XL500 engine. “It has the air cooled cleanliness and overall layout that I wanted. As well as being a four valve head with parallel twin exhaust ports, the late 70s to early 80s engines also had fairly pretty cases and covers compared to the later XL650.”
Niki handled all the design and fabricated most of the parts, but wisely handed over the CNC milling and composite laminating to experts. “I enjoy doing laminating—and make my own surfboards—but a friend is a very experienced laminator, and he offered to help with the carbon parts.”
The starting point was CAD. “I do basic design sketches to capture what I am imagining, and then start CAD modeling to see what will work and what won’t.”
Niki’s preferred software is Autodesk Alias, which he’s used extensively for 20 years in his day job. “Its strong point is developing refined surfacing, but it’s also good at outputting data to be CNC’d or 3D printed.”
With the XL500 engine three dimensionally scanned, Niki started working on the layout and proportions. He had the tire size set at 26 inches, and aimed for a riding position that left his six-foot frame slightly stretched out.
He also wanted a subtly raked feel to the profile, and ended up raising the centerline of the tank slightly, to avoid the front suspension becoming the tallest point on the profile.
The steering is packaged in between the suspension arms, suspended on a combination of radial and thrust needle roller bearings. And the bars drop out and down, helping to lower the visual weight of the bike down too.
Niki’s given the front suspension a steeper than normal geometry, thanks to the higher axle and large diameter tires. The wheels were troublesome: after an abortive attempt at machining the tire seats into carbon fiber rims, Niki switched back to steel.
Carbon fiber spokes are hooked up to CNC machined hubs on large hollow axle bolts. “I found the largest wheel bearings I could fit inside the brake rotor spider, and made them the basis for everything around the hub, matching the profiles of the rotors and sprocket carrier to the hub.”
Niki’s also experimented with different fabrication techniques, including ‘investment cast’ parts—as you might find on a lugged bicycle frame. “I was able to 3D print positive parts to take silicone molds from, which in turn allowed me to pour the investment wax pieces.” All of the frame tubing is made from 4130 chromoly, and it was possible to have the cast parts made in the same material.
Using a homemade jig, Niki then fixed the position of all of the key components, and joined them together with traditional fabrication.
The seat is a blend of the traditional board track seat and Niki’s old Kashimax Aero BMX seat, modeled in clay, scanned into CAD, and then made in carbon fibre and Kevlar.
It’s cantilevered off the back of the frame in an effort to create some extra comfort. “The tire profiles are very low and the air shocks quite basic, so this really helps the ride quality!”
The exhaust system was a particular point of pride. “I grew up in my Dad’s workshop learning to make exhausts, so I wanted to do a good job on this part,” says Niki.
The fuel tank is actually a split design, constructed in carbon fiber and fiberglass composite, with brass fittings. The inside of each half is hollowed out, creating a space between the tanks to hold the front shock and a compact 6V battery, plus the regulator, rectifier and electrical loom.
The colour scheme is intentionally dark. “I wanted to show the carbon fiber, but not in an overt manner—the contrast to the surrounding black is relatively subtle,” says Niki. There’s little in the way of decoration, aside from brass badges on the tanks.
The Honda wowed the judges at The Quail, and it’s wowed us too. As a 21st century re-interpretation of a classic board track racer, it’s just perfect—and also an astounding showcase for Niki’s design and fabrication skills.
Niki Smart | Instagram | Images by (and thanks to) Paulo Rosas of Speed Machines Design
