Race spec: A Triumph T140 track bike inspired by Steve McQueen’s TR6

Triumph T140 race bike by 46Works
Mentioning ‘Triumph’ and ‘Steve McQueen’ together conjures up images of the iconic desert sleds that the King of Cool kicked up Californian dust with. This custom Triumph T140 Bonneville takes inspiration from one of McQueen’s most famous bikes—his number 955 TR6 desert racer. But it’s been built for a very different purpose.

The 1976-model T140 lacks a desert sled’s long travel suspension, big wheels, and tall handlebars, because it’s been designed to dominate on the track instead of in the dirt. More specifically, it’s been custom-made by Shiro Nakajima at 46Works to compete in the Japanese Legend of Classic race series.

Triumph T140 race bike by 46Works
We can’t think of a better man for the job than Nakajima-san. A regular on our pages, he’s probably best known for founding the Japanese restomod powerhouse Ritmo Sereno—but he’s also a furniture maker, a vintage car restorer, and one heck of a motorcycle builder.

Shiro lives and works in a charming traditional wooden building, tucked away against the foothills of the Yatsugatake Mountains where scenic B-roads abound. But he still regularly makes the trek to the Tsukuba Circuit a few hours away, where he races the classic race bikes that he’s so adept at building. So he knows how to make older bikes look good and go fast.

Triumph T140 race bike by 46Works
Shiro put the Triumph T140 Bonneville together for a customer, who supplied nothing more than the frame, swingarm, and engine. McQueen’s ‘955’ offered design inspiration, but it was up to Shiro to add all the right mods to make the T140 track-capable.

Right away, the engine went off to Gladstone, a Triumph specialist in Shizuoka, for a full rebuild. It came with high-compression pistons, upgraded camshafts, a modified head, and a belt drive conversion. Also present are a Quaife five-speed transmission kit, and a pair of Keihin CR carbs.

Triumph T140 race bike by 46Works
From there, Shiro set about building the chassis—starting with tweaking and reinforcing the frame. The front forks come from a Yamaha (Shiro won’t say which), and have been rebuilt with new internals. They’re held in place by a set of machined aluminum yokes, connected to a custom steering stem.

The Triumph T140 rolls on 18” Excel rims, laced to two different Yamaha hubs with brand-new Yamaha spokes. There’s an Avon Roadrider wrapped around the front wheels, with an Avon Super Venom AM18 out back.

Triumph T140 race bike by 46Works
Thanks to the new wheels, the bike benefits from a major braking upgrade. It now uses two AP Racing calipers up front and a single Brembo caliper out back, with Sunstar discs and Brembo master cylinders at both ends. (There’s no ABS, but the T140 should stop quicker than it did in the 70s.)

Equally impressive are the bespoke rear-set foot controls, and the myriad linkages that make them function. And since this is a race bike built by an experienced racer, there’s safety wire in all the right places.

Triumph T140 race bike by 46Works
Moving to the bodywork, Shiro pieced together a set of parts that come as close to mimicking McQueen’s Triumph as a track bike can. The fuel tank is a reproduction Triumph unit, while the seat, which looks like a classic Bates number, is a one-off. Shiro built the aluminum seat pan, and then handed it over to Razzle Dazzle for foam and upholstery.

The rear section follows the traditional desert sled formula of a three-quarter seat, a kinked subframe, and a long alloy rear fender. At the opposite end of the bike, Shiro replicated the style of fairing and fairing brackets found on McQueen’s bike, but with a stubbier design.

Triumph T140 race bike by 46Works
The twin shotgun-style exhaust pipes are another nod to the TR6 sled, right down to the way that the ends are stacked. They’re also a testament to Shiro’s craftsmanship, since he hand-bent the headers out of titanium. Aluminum number boards add to the bike’s vintage appeal (and give the owner somewhere to stick his race numbers).

Other details include a Setrab oil cooler with Kinokuni fittings, a handmade oil catch tank, and a battery mount that offers quick and easy access. Shiro wired the bike from scratch too.

Triumph T140 race bike by 46Works
The cockpit sports low-rise handlebars fitted only with the most basic controls. A custom dashboard hosts a Stack tachometer, a single warning light, and a Daytona temperature meter, while a lap timer sits atop the bar clamps. There’s nothing unnecessary on this T140; every last inch of it has been fine-tuned for Shiro’s customer, “so that he can win races.”

Even the livery is all business. Rather than fully mimic the McQueen bike, this Triumph opts for a simple coat of jet black with period-correct logos. Top work by regular 46Works collaborator, Drops Design Works.

Triumph T140 race bike by 46Works
46Works’ custom Triumph T140 might not be the first thing we picture when we think of a classic Triumph track bike, but that’s what we love most about it. It’s also refreshing to know that it’ll be used as intended—as we write this, Shiro’s at Tsukuba making sure it goes as good as it looks.

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Triumph T140 race bike by 46Works

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