Analog Motorcycles’ Custom BMW R90/6

[Hugh Janus]

Tony Prust leading the way on the 2019 Built to Ride Tour. (Monti Smith /)

With a $10,000 prize on the line, Tony Prust of Analog Motorcycles approached the Built to Ride Tour with a plan. The rules are simple—show up with your bike, ride from stop to stop, and at the end of each day, the public votes on which custom bike they liked the most. At the final stop of the tour, the votes are tallied and the builder with the highest total wins the prize. No second place, no input from the editorial staff. With roughly 700 miles of riding from day 1 to day 4, Tony brought a highly modified 1976 BMW R90/6—a bike that would not only handle the distance with ease, but strike just the right balance between custom and classic to take home the big prize as well.

1976 BMW R90/6 built by Analog Motorcycles. (Monti Smith /)

I first met Prust at The Quail Motorcycle Gathering in 2015, when he brought his custom 1949 Indian Scout café racer out from his home in Chicago and won Best Modified/Custom Class. I had seen him at other motorcycle shows over the years, always with some brilliantly updated classic motorcycle. Sure, he works on modern bikes, but after looking at his lineup of past work, it’s clear he leans toward the older platforms when starting a build. But one thing I hadn’t known about Tony until the tour? That dude can ride.

Öhlins shocks, Analog Motor Goods subframe, machined hubs, custom seat—yet still maintaining a classic BMW feel. (Monti Smith /)

Tony tries to get out to the track as often as he can, and he’s not the guy who has an old Honda RC51 in the garage, no, he builds these bikes up to actually handle and perform as best they can—by modern standards, not those of the time they were initially built. Looking at the BMW, I’m sure many of the passersby paid no mind to the incredible amount of work that was put into this machine, but that’s sort of the brilliance of it. The chassis has been upgraded, the lines have been smoothed and enhanced, the engine’s performance has been totally upgraded, but when you step back and look at it—it’s still an R90/6.

Split valve covers on the R90/6’s boxer engine. (Monti Smith /)

Starting with the chassis, an Analog subframe was installed with Öhlins shocks mounted to it, and the swingarm braced. The fork was disassembled and rebuilt with Race Tech Gold Valve Emulators and lowers to run dual front brakes, mounted to Analog’s own triple trees and bar clamps, then braced for stability. The hubs of the wheels were machined and modified, then laced up himself with spokes from Buchanan’s Spoke & Rim out in California. Now that the bike was able to turn and stop, it was time to focus on the “go.”

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Analog Motorcycles’ 1976 BMW R90/6. (Monti Smith /)

The engine was rebuilt by Motorworks Chicago with a Siebenrock 1,000cc big-bore kit. The stock flywheel was lightened and a larger, deeper sump was installed to increase the engine’s oil capacity. A new K&N air filter is used inside the drilled-out airbox and paired with Analog’s own slip-on muffler kit to increase airflow all around. Two Mikuni round-slide carbs replaced stock units, and a Boyer Bransden electronic ignition system was set up for timing. Last but not least, a set of split valve covers are bolted to heads—another subtle detail that those in the know get very excited about. The bike now puts out more power, revs up quicker, and cools itself more efficiently.

Motogadget controls, turn indicators, and mirrors keep things tidy at the handlebars. (Monti Smith /)

The stock R90/6 gas tank was maintained, helping keep the classic BMW aesthetic, but Analog Motor Goods badges replace the originals. A custom rear fender was fabricated and the stock front was trimmed up a bit. The seat pan and corresponding battery box were fabricated in-house, then the seat was shipped off to Dane Utech (@plzbeseated) for upholstery. Once all the bodywork was done, classic BMW-style paint and pinstriping were handled by Artistimo Custom Design in Wisconsin.

A custom choke removal cover bearing the Analog Motorcycles logo. (Monti Smith /)
A custom housing was made to fit the new Daytona Digital gauge into the back of the headlight. (Monti Smith /)

From both an aesthetic and functional standpoint, most of the bike’s now-modern feel comes from the components at the handlebars. Renthal bars were fitted with a suite of Motogadget components including m.Switch Minis to handle the electrical components, m.Blaze bar-end turn indicators, and m.View dropdown mirrors, with the whole bike wired through a Motogadget m.Unit wiring system. Finally, powdercoated levers were mounted to a Magura clutch perch and master cylinder.

Tony Prust’s custom BMW on a back road outside of Johnson City, Tennessee. (Monti Smith /)

Tony’s build perfectly walks the line between classic and custom. Those who don’t know what they’re looking at will see a beautiful vintage bike. Those who do can appreciate the time, effort, and good taste that went into putting this machine together. And it managed to make it the 700 miles of the Built to Ride Tour without a single hiccup. Prust managed to hold a consistent lead in the polls throughout the Tour and it was announced on the final day that he was the grand champion, taking home the $10,000 prize. He has been invited back to the 2020 tour, and we can’t wait to see what he brings.

The 2019 Built to Ride Tour invited lineup. (Monti Smith /)

For more information on the 2020 Built to Ride Tour, head to builttoridetour.com.

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