Motorcycles

Bottpower's XR1R flat tracker puts the Buell XB12 on a little-needed diet

Bottpower's XR1R flat tracker ...
Bottpower XR1R: 150 horsepower, 150 kg and a heart of Buell
Bottpower XR1R: 150 horsepower, 150 kg and a heart of Buell
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Bottpower XR1R: minimalist seat pad speaks to its track focus
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Bottpower XR1R: minimalist seat pad speaks to its track focus
Bottpower XR1R: teardrop tank and chunky switchgear
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Bottpower XR1R: teardrop tank and chunky switchgear
Bottpower XR1R: seat pads are probably not what most 'botts' would describe as luxury
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Bottpower XR1R: seat pads are probably not what most 'botts' would describe as luxury
Bottpower XR1R: unmistakeably Buell-based
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Bottpower XR1R: unmistakeably Buell-based
Bottpower XR1R: flat number plate
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Bottpower XR1R: flat number plate
Bottpower XR1R: accessible shock for suspension adjustment
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Bottpower XR1R: accessible shock for suspension adjustment
Bottpower XR1R: top spec Brembo master cylinder
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Bottpower XR1R: top spec Brembo master cylinder
Bottpower XR1R: hand adjustable Ohlins shock under the seat
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Bottpower XR1R: hand adjustable Ohlins shock under the seat
Bottpower XR1R: Renthal grips and nicely machined switchgear
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Bottpower XR1R: Renthal grips and nicely machined switchgear
Bottpower XR1R: electric start has been removed to save weight
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Bottpower XR1R: electric start has been removed to save weight
Bottpower XR1R: launch control, pit land speed limiter and... Is that a thumb operated quick shifter?
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Bottpower XR1R: launch control, pit land speed limiter and... Is that a thumb operated quick shifter?
Bottpower XR1R: multiple power modes are selectable on a knob
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Bottpower XR1R: multiple power modes are selectable on a knob
Bottpower XR1R: the tiny headstem is one of the only visible bits of frame
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Bottpower XR1R: the tiny headstem is one of the only visible bits of frame
Bottpower XR1R: trademark Buell belt drive
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Bottpower XR1R: trademark Buell belt drive
Bottpower XR1R: set to challenge Pike's Peak in 2017
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Bottpower XR1R: set to challenge Pike's Peak in 2017
Bottpower XR1R: an American-style flat tracker built out of an American legend... Built out of another American legend. In Spain.
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Bottpower XR1R: an American-style flat tracker built out of an American legend... Built out of another American legend. In Spain.
Bottpower XR1R: the team is aiming for more than 150 horsepower and less than 150 kg
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Bottpower XR1R: the team is aiming for more than 150 horsepower and less than 150 kg
Bottpower XR1R: retains the powerful Buell ZTL rim-mounted brake disc
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Bottpower XR1R: retains the powerful Buell ZTL rim-mounted brake disc
Bottpower XR1R: track-only version of Bottpower's XB series Buell kit bikes
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Bottpower XR1R: track-only version of Bottpower's XB series Buell kit bikes
Bottpower XR1R: 150 horsepower, 150 kg and a heart of Buell
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Bottpower XR1R: 150 horsepower, 150 kg and a heart of Buell
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Bottpower's XR1R is an American-style flat tracker from Spain built from an American legend (Erik Buell's revolutionary XB12) that was built from another American Legend (Harley-Davidson's Sportster 1200). With more than 150 horsepower and less than 150 kg (331 lb) to shift, it should be a mad little racetrack carver, and it's set to challenge Pike's Peak in 2017.

I've never considered the old Buell XB12 as a bike with much fat to trim. In its day, it was a revolutionary machine – check out Mike Hanlon's write-up of the XB12S from back in 2004, when mass centralization was still a brand new idea in the bike world, and the XB12's 175-kg (386-lb) weight was nigh-on unbelievable for a 1200cc bike with a heavy Harley engine and a full set of road compliance gear. Devastatingly nimble in the corners, it still makes a lot of people's lists as one of the best handling road bikes of all time.

And yet here we are 14 years later, looking at a kit bike custom that throws out that famous Buell fuel tank frame in search of an even lighter and more responsive ride.

Bottpower XR1R: flat number plate
Bottpower XR1R: flat number plate

Unfortunately named Spanish engineering shop Bottpower has been building a flat tracker kit for XB donor bikes since 2012 in the form of the XR1. There's a strangely bulbous cafe racer version as well, and they've just released this tasty track-only version called the XR1R.

The XR1R looks for all the world like a frameless motorcycle, but in truth its tiny teardrop tank, seat and subframe are held to the motor with a miniscule titanium frame that runs over the top of that big 1200cc Harley motor, and only peeks out at the steering head.

Bottpower XR1R: the tiny headstem is one of the only visible bits of frame
Bottpower XR1R: the tiny headstem is one of the only visible bits of frame

Beyond that, a lot of Buell remains, including the famous twisted pipes, the Zero Torsional Load rim-mounted front brake, the underslung exhaust and rubber belt drive. But the engine's now managed by a Euro IV-compliant ECU that adds traction control and launch control to the menu as well as multiple engine modes and a pit lane speed limiter.

The team has fitted an advanced datalogger that maps throttle, rpm, the speed of both wheels, suspension travel, GPS location, temperatures, brake pressures and more for post-session analysis – that's some pretty serious gear. And because Bottpower is testing the titanium frame against the steel one used in the road-going XR1, they're also logging frame stress at several different points.

Bottpower XR1R: an American-style flat tracker built out of an American legend... Built out of another American legend. In Spain.
Bottpower XR1R: an American-style flat tracker built out of an American legend... Built out of another American legend. In Spain.

When all is said and done, the team is looking for more than 150 horsepower (112 kW) and less than 150 kg (331 lb), which will make the XR1R a furiously fast little beast, an overgrown motard with a hard-pumping American heart.

Exactly why you'd try to build around that Harley Sportster motor in this day and age remains a bit of a mystery to us. It's a good looker and sounds great, but it's heavy and sloppy and low-tech from a performance standpoint. Still, this reinterpretation of one of Erik Buell's most iconic designs looks like a hell of a lot of fun. Check it out from all angles in the gallery.

If things go to plan, we might see the Bottpower XR1R contesting the Pike's Peak Hill Climb in 2017. We wish the team the best of luck!

Product page: Bottpower XR1R

View gallery - 20 images
3 comments
gizmowiz
Looks like a dog with it's tail cut off.
Imran Sheikh
Beautiful, if i get my hands on it the first thing i do is chop that "giant ugly 2" written below the Seat.