One of the displays at Dan Rouit’s flat track museum is a Royal Enfield built by Shell Thuett in the early 1960s. The 500 single was used to set a longstanding lap record at Ascot, back when that really meant something. Thuett’s dead and Ascot’s long gone, but after a roughly 50-year hiatus from top-level racing, the Royal Enfield brand will reappear at the next AFT “National,” with a svelte Production Twins bike under part-time pro Johnny Lewis.
The Production Twins racer began life as a show bike, built for last year’s EICMA trade show in Milan. The project was under the control of Adrian Sellers, who is in charge of custom projects at the new Royal Enfield UK Technology Centre. Sellers tapped Harris Performance to build the chassis. (Harris, like RE, is owned by Eicher Motors.)
Although Harris is known for road racing, the company delivered a pretty credible monoshock flat track frame, housing an Interceptor 650 twin engine, built up with a 750 cc big-bore kit and custom high pipe from S&S (which has been expanding its catalog of RE custom parts for the last few years). The result was a handsome custom that Royal Enfield dubbed “Twin FT.” The response at EICMA was so positive they decided to actually race it.
Royal Enfield already had a strategic relationship with S&S, which is a company with a lot of institutional knowledge when it comes to flat track. But since S&S runs Indian’s factory team, it couldn’t take on the assignment of turning RE’s Twin FT show bike into a genuine go bike.
Paul Langley, at S&S, introduced Sellers to Johnny Lewis, a part-time pro flat tracker who runs a coaching program called Moto Anatomy. Lewis is a good choice for an underdog effort, since he’s run in the top 10 on both Triumphs and Ducatis. In fact, he may be the active rider who’s ridden the most different brands. He’s also entrepreneurial and quite happy to serve as team owner, manager, and rider. Royal Enfield flew Lewis to England in December.
“It was cold and wet,” Lewis said. “I just rode it on an airport runway, but I gave them some feedback. Because I’m six feet tall, I needed them to extend the tail section so that I could get into a tuck. The fuel tank from the show bike needed to be wider, because in dirt track you push your right knee into the tank.” Lewis also told them to change the steering offset, and build in more adjustability.
COVID-19 hit the U.K. hard and wrecked the original plan to deliver a revised bike to Lewis’ training facility in Florida by March. Of course then, the AFT season was postponed too, which bought some time. Even though the bike’s still never been raced, Lewis is enthusiastic about working with Harris Performance and Royal Enfield’s tech center. He told me that new components arrive for testing almost as soon as he’s made suggestions.
Notwithstanding the word “production,” the Production Twins rules allow a very wide latitude when it comes to engines. Basically, the engine castings must begin as production items, and that’s it. Having said that, the air-cooled Continental 650 motor has a very different architecture than, say, the liquid-cooled Kawasaki 650 twin which — along with the Yamaha MT-07 and Harley-Davidson XG750R — fills most of the Production Twins grid.
The Yamaha and Harley are long-stroke motors, too, but to make a study in contrasts, let’s compare the Royal Enfield to the Kawasaki. The RE has a 67.8 mm stroke and a 270-degree crank, while the Kawasaki has a 60 mm stroke and 180-degree crank. I know of Kawasakis being raced with 64.4 mm stroker cranks. But the Continental GT’s long stroke will define its character as a race engine.
“We’re still waiting on new pistons,” Lewis told me. “But the motor already produces great torque. You have to ride it different. It makes its power below 9,000 rpm, compared to the Kawasakis that spin to 10, 11, or even 12,000 rpm.”
Lewis got the chance to compare his test mule to some AFT Production Twins bikes a couple of months back, over the Memorial Day long weekend.
“I promote a series called ‘Flat Track Futures’ at Traveler’s Rest Speedway in South Carolina,” he told me. “Over the Memorial Day weekend, we had a $10,000 purse and it might as well have been an AFT National. I had transponders on all the bikes, so I know everyone’s lap times. I couldn’t race because I was too busy, but I went out on the Monday, and we’ve already achieved our expectations. The chassis will be good. All we need is another 10 horsepower.”
No one at Royal Enfield has shared dyno charts with me, but the company claims the stock 650 cc Interceptor produces a peak 47 horsepower at 7,250 rpm. Although the shape of the torque curve’s at least as important in flat track, one team owner who’s built competitive air-cooled twins told me that in today’s AFT Production Twins class, 85 horsepower would be the minimum requirement for shorter tracks. That seems achievable.
On mile tracks, a competitive bike needs 95-plus horsepower; that’s a taller order. Luckily, only two mile races are on this year’s schedule (the Springfield doubleheader). “We hadn’t planned on doing the miles anyway,” Lewis told me.
The revised season schedule might help Lewis and Royal Enfield, because back-to-back doubleheader races will allow the team to try different things without waiting weeks between races. “I can almost get more races on the revised schedule than I would’ve had on the original one,” he said. “And they’re not horsepower tracks. They’re all tracks where I’ve been a top-10 guy.”
One team owner I spoke to seemed to agree, telling me, “‘Stadium’ TT tracks, short tracks and 3/8-mile tracks could be won by a well sorted chassis with an air-cooled 800 for sure in Production Twins, especially with a rider of Johnny Lewis’ talent.”
The second round in the revised AFT schedule, which was to be held on the always-spectacular half-mile pea-gravel cushion track at Lima, Ohio, has been postponed due to COVID-19 concerns. So, the next race won’t happen until late August, at a northeast location that’s still “TBA.”
Another long delay gives Lewis and Royal Enfield that much more time to get ready, but it means we’ll have to wait to see a bike that, at the very least, will make a visually striking old-school, air-cooled addition to the Production Twins grid.
A flat-track trainer based on the Himalayan
Over the past year, Royal Enfield has also worked with S&S to develop the FT411 flat-track kit, a set of parts that turn the affordable Himalayan ADV bike into a beginner-friendly flat track training tool. The key elements of the kit are 19-inch Warp 9 rims laced to the stock hubs and a racy exhaust that’s routed inside the frame and under a new, carbon tail section. That exhaust routing mod reduces the risk of crash damage, but requires repositioning the battery and replacing the airbox with a more traditional air filter.
Controls are also modified. There’s a new Vortex handlebar with a suitable bend, new clutch perch and lever, new brake pedal, and a new gear lever that works with a raised left footpeg (required for cornering clearance).
So far, only about 20 kits have been put together. There’s a few FT411s at S&S’s private test and training track in western Wisconsin, and a few in India (although because they can’t get 19-inch flat-track rubber there, the Indian bikes have 18-inch wheels).
Johnny Lewis is involved in this project, too, and he’s already using a small fleet of FT411s at his Slide School, which is a half-day intro to flat tracking. Similar schools, such as American Supercamp, for example, teach beginners on minibikes. Lewis prefers to start students on full-sized bikes with proper flat-track wheels and tires, because he feels it makes it easier for them to transition to a real race bike, or apply what they’ve learned on their own full-sized motorcycles.
“It’s heavier than a minibike,” Lewis told me. “But it’s really well balanced. At 25 horsepower, it’s more powerful, too, but the power’s really linear, so it’s not intimidating.”
The FT411 looks like so much fun that I immediately asked S&S boss Paul Langley about buying at kit for myself. He didn’t exactly throw cold water on that idea, but he cautioned me that the kit is not quite commercially available.
“Right now, the kit would be fairly expensive,” he explained. “Our goal is to manufacture all the components in India, except for the exhaust, which we can make affordably here. We’ve been over there looking, but haven’t quite settled on suppliers yet.” So, it remains to be seen when the kit might be available through your local dealer and what it will set you back.
It looks like a great practice and training tool, but I think it would make a terrific spec-racing class, too.
Like me, you may already have thought of using the kit to create a nominally road-legal street tracker (or a bike that you could ride to a local short track, train on, then ride home). When I asked about that, Paul Langley cautioned me that the existing exhaust is a race-only item that doesn’t meet emissions controls. He warned that the California Air Resources Board and regulators in other states are cracking down on the use of such pipes on street bikes. However, he told me one of the things S&S has on its to-do list is to create an emissions-legal pipe for the Himalayan that has the same inside-the-frame routing.