Mushman Runner: Yamaha XS650 Desert Sled

What if Steve McQueen aka Harvey Mushman decided to build and race an XS650?   

In a strange twist of fate, the Yamaha XS650, introduced in 1969, took up the standard of the British twins that were going the way of the dinosaurs. As the storied British factories shuttered their doors, the XS650 came onto the scene as an oil-tight, surprisingly modern parallel-twin that echoed the style, sound, and character of the Triumphs, Nortons, and Beezers that preceded it.

Given these parallels, we’ve always thought the XS650 would make a great candidate for a Southern California-style desert sled straight from the days of On Any Sunday. We’ve even eyed our own XS for such a build, and we’re surprised we’ve never seen anyone take this tack…until now!

Not surprisingly, the man to come up with the idea is our buddy Yann from BCK Motorcycles, one of today’s builders most tuned in to the history of two-wheeled desert racing. This project was an exercise in alternative history. What if, in the early 1970s, Steve McQueen aka Harvey Mushman (his racing alias) turned his eye to the new 650 XS?

“Suppose for a moment that, while Bruce Brown is putting away the reels of his mythical film On any Sunday (1971), curiosity pushes the famous Californian actor to fill in his nickname Harvey Mushman and his lucky number 48 on a registration form for a Baja event riding this Japanese twin.”

Yann built the bike as legendary Bud Ekins — McQueen’s buddy, fellow racer, and bike builder — might have done it, adapting available Triumph parts where possible. Yann fabricated the high-mount stainless exhaust, fork brace, front number plate, and an electronics compartment. He shaped the seat foam in-house and his buddy Nikau from NCW Workshop upholstered it in that old Bates cross country style.

The wheels are 19″ F/ 18″ R — standard ‘sled sizes — and to remain more period-correct, Yann used as a twin-cam front drum brake from a Bullet 500. The chassis was sandblasted and powder-coated, and the engine rebuilt by Gougou, a former Isle of Man TT motorcycle bike tuner.

To make the build even more special, this engine comes from Yann’s very first custom build in 2008! It went through a couple of negligent owners before finding its way back to him. Fittingly, it’s been rebuilt better than new and put in a bike that marks a new era for BCK Motorcycles:

“The aim with this last one is to open a new chapter in my workshop’s history with some vintage looking off-road racers, which are ultimately some of the ones I love to build.”

We’re suckers for alternative motorcycling histories, and this is one of the most fun and creative we’ve seen. Bravo, Yann, for a lovely build — we hope you enjoy your time in the desert with this one, and your upcoming time in the American West!

Below is our full interview with Yann about the build with many more photos and details.

650 XS Desert Sled: Builder Interview

• Please tell us a bit about yourself, your history with motorcycles, and your workshop.

Yann from BCK Motorcycles, previously BCKustoms. Living with and for two wheels for decades, I’m a true great fan of the history of motorcycles, and I’m now a bit afraid of some commercial and technological directions taken to sell them today. So I have more interest in looking over my shoulder to the machines and people who made that history so intense and incredible.

After some years as a race mechanic ending with the role of Team Manager in the World Championship series, I opened a garage to build projects between friends in 2010. In 2019, this nice hobby became a racing activity, which led to a full time job starting with flat track activities.

• What’s the make, model, and year of the bike?

Actually, this Yamaha XS650 is a ’76 model with an ’82 SE engine.

Just to make a step back, the engine comes from my very first build back in 2008, the year I bought a complete US Custom Special XS650 while working in Belgium to start a bobber project inspired by the famous “Harper” built by the one and only Fred “Krugger” Bertrand.

The bike was sold in 2013 to a fool surfer who just ruined the engine in burnouts as he finally didn’t get his license. Then the bike was sold to a tattoo artist who struggled to get it working properly. I got the bike back in exchange for a running XS chopper project found on Ebay.

So my first ever build was back home and left in this condition, with a semi empty engine visited by a supposed famous XS Specialist who couldn’t handle the problems. Nice joke.

• Why was this bike built?

Bruce Brown has really entered my head and left a full, un-rushed copy of On Any Sunday. What a film!! I love desert racing and my last trips to the Spanish deserts have only increased my interest in great space rides, in the middle of nowhere. I follow all Baja and desert races online, watch again and again Johnny Campbell flat out with his XR in the Terrafirma 3 opening scene, and could be planning to attend the NORRA Mexican 1000 in the next few years with my own bike, which has to be a vintage one.

2019, a long time ago, I built a pure Scrambler from an XS500 and the result went pretty easily. A great attention was already given to stainless exhaust pipes, which is a detail I love to design and make. Once you’ve added all necessary typical scrambler accessories inspired by the story of that kind of race, then you have a great bike.

Last year, I built my first true desert sled “El Jalapeño” with a Suzuki GN125 inspired by the Biltwell “El Frijole.” That small bike is a blast in the Andalusian desert of Gorafe, on both rocks and sandy tracks, and has been so much fun. So I decided to go for a bigger version of it, with “borrocks” as would say Nitro Nori Haga.

I have seen logically too many Triumphs and BSAs around to enjoy making another one. So what if Let’s get a step back and watch history for a second. Imagine for just a moment. Since the mid-sixties, legions of amateur pilots have lined up on starting lines, in the middle of hundreds of others like them in the desert. With their eyes fixed on the black smoke of the pile of tires burning on the horizon that marks the first check point of the race, they rush forward. Among them, there are also big names like Malcolm Smith and Mert Lawwill or celebrities like Steve McQueen.

The latter has also acquired such an aura in the motorcycle industry that his opinion makes the cover of magazines, for which he details and compares the different models available (Popular Science Magazine, November 1966). His passion for racing motorcycles and competition permanently places him in search of performance. He seeks to understand and adapt the improvements that will make him go even faster.

It is there that in 1969, Yamaha will release its response to the overwhelming domination of the English twins who came to replace the overly heavy American twins. The 650 XS will conquer that place in the market due to its more standardized design and its unparalleled reliability for the time. It will then follow the development in competition to finally win titles in ’73 and ’74 on ovals at the hands of young talented Kenny Roberts. The machine is therefore officially recognized as a very good racing machine base in turn.

Suppose for a moment that, while Bruce Brown is putting away the reels of his mythical film On any Sunday (1971), curiosity pushes the famous Californian actor to fill in his nickname Harvey Mushman and his lucky number 48 on a registration form for a Baja event riding this Japanese twin.

Letting his friend Bud Ekins collect and adapt from here and there parts used before, here is an interpretation of what McQueen’s Yamaha XS650 would look like in Desert Sled mode. And what if?

• What was the design concept and what influenced the build?

Talking desert sleds, one is standing like an icon itself. The 1963 McQueen T120 put on sale at Bonhams a few years ago has defined for me what is the best twin four-stroke ride for the 60s motorcycles. Built by Bud Ekins, monochrome painted by Von Dutch, the lines of the bike are awesome, just underlined by all the most iconic equipment such a bike must have: a solid fork brace, a Bates cross country seat, a decent cotton air filter to give the engine fresh air, and a reliable skid plate. And the most important, a high twin stainless exhaust sticking to the engine to avoid leg burns and allow kick starting.

• What custom work was done to the bike?

The story I wrote prior to the build was allowing Bud Ekins to use old Triumph racing parts to set up that XS project. So the exhaust could be a Triumph element lightly modified, a Bates seat, and a Triumph fuel tank which increase the mileage. Longer shocks of course and knobby tires are completing the project. No accessories, all non-necessary parts removed like lighting system and stands, painted graphics and stickers to make the bike the lighter possible.

So on my side, I made the exhausts, the fork brace, the front plate, and the electric compartment to store all necessary original electrical parts. The seat foam has been shaped at home on an alloy plate, like the skid plate, and has been covered by my friend Nikau from NCW Workshop.

Because the original XS had a front disc brake, which wasn’t “period correct,” I found a new Royal Enfield 19” front wheel with a twin-cam drum brake from a Bullet 500.

The chassis has been sandblasted and powder coated once again by Patrick Le Page, while the engine I had since 2008 was fully rebuilt by Gougou, a former Isle of Man TT motorcycle bike tuner for over 10 years.

As the bike was initially supposed to go in the desert and not on stage, all the paintwork has been homemade with spray paint. Let’s say this was built for the race, not for the show.

• Does the bike have a nickname?

The Mushman Runner, of course!

For the last 5 years, all off road projects leaving the workshop have a nickname ending with Runner. From the 2020 Dezert Runner based on a BMW F650 Funduro forward, every new bike has to be named after the man who influenced his build. The McQueen runner would have been pretentious, as the guy already a long list of bikes and cars he owned. So Harvey Mushman’s name is also to push people to search for information and get the story.

• Can you tell us what it’s like to ride this bike?

This bike has finally been finished just three weeks prior to my departure for Gorafe, but a last minute call offered me the opportunity to put it on stage for the ArtRide X at the 2025 Wheels & Waves festival in Biarritz. So, despite all my wishes to get it started, it’s not done yet.

• Was there anything done during this build that you are particularly proud of?

As usual, the project has been drawn scale 1 on the computer. I use a simple drawing software, not a 3D one, and it’s enough to adjust the parts together like the exact positioning of the Bonneville gas tank on the XS frame and the choice of shocks length to get the overall bike in the correct position with both wheels in correct desert sled sizes, 19 front and 18 rear.

After all the vintage looking bikes I built, from a Honda XL tuned into Elsinore style, Suzuki DR looking like a Husky MX, this XS is kind of an achievement, a true vintage off-road unicorn I wanted to build and ride for a while.

The aim with this last one is to open a new chapter in my workshop’s history with some vintage looking off-road racers, which are ultimately some of the ones I love to build.

Builder Thanks

Special Thanks to all locals helpers and craftsmen who responded really quick to my request:

• Full engine rebuild by Master Gougou, IOMTT race bike wizard
• Upholstery by Nikau at @ncw_workshop
• 3D printing @recreaju
• Stainless welding @jefracfrac at @t2xc.creation
• Sandblasting and powdercoating by Patrick at SARL LE PAGE

And big thanks to the companies who helped me to give that project a go
All lubricants by @iponelube
Restoration products issued by @wd40_france
All finishing products from @noline.france

A special one finally to @upshift_online and the #ridemore for the daily dose of motivation and the Yee-Haa Papa Crew, the one and only supporting me everyday. Love you.

The photo shoot was made in a true magic place: @cueva_aventura, Benamaurel, Andalusia, Spain (www.cueva-aventura.es). You have to visit and you’ll be told of all the nice tracks around. Thanks Laurence and Christian.

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Website: www.bckustoms.com
Instagram: @bckustoms
Facebook: facebook.com/breizhcoastkustoms/

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