Then in March, Robertson opened Speedin' Motorsports at 1826 E. Mojave St. in Farmington. In addition to parts and accessories, Robertson offers race tuning and trackside support for racing bike enthusiasts.
"The demand just kind of grew to the point where I needed a shop to conform to the local codes," he said.
Robertson, 26, took a winding road to entrepreneurship.
He was born and raised in Farmington and is a 2005 graduate of Farmington High School. Robertson studied automotive technology at San Juan College before working as a technician at Ziems Ford Corners, a local car dealership.
Finding that automotive mechanics didn't pay as well as he'd expected, Robertson went into the oil and gas industry as a pipeline operator for Western Refining Inc.
All the while, he was growing his own business by word-of-mouth.
"One buddy would order from me and tell his buddy, and another buddy would tell his buddy," Robertson said.
Eventually, Robertson's wife, Cassandra, tired of having their home full of motorcycle parts and encouraged him to start his own business.
"Definitely without her this wouldn't be possible," he said.
Robertson is the sole proprietor of Speedin' Motorsports, with a little help from his parents, Bill, a safety engineer for WPX Energy, and Charlene, who is retired.
Robertson does everything himself, from repairs to ordering to accounting. He has no employees.
"That's something I take a lot of pride in," he said. "I don't want to pass a customer off to someone else."
Robertson is part of a tight-knit subculture of sport bike enthusiasts in San Juan County.
He travels to races for the business and also races himself.
He typically rides a 2007 Suzuki 65XR 600. He also built from parts a 2008 Yamaha R6.
Speedin' Motorsports focuses on sport bikes but will work with Harley-Davidsons and all-terrain vehicles.
Robertson is good friends with Brandon Prince, who runs a competing shop, Motorcycle Performance Headquarters, at 616 E. Main St., with his father, Allen.
"I don't see it as competition," Prince said. "Each of us has our own niche. I've sent people down to Brian, and I know Brian's sent people down to us."
Motorcycle Performance Headquarters focuses on high-performance Harley-Davidson parts and tuning.
"We try to cater as much as we can to everybody," Prince said. "Being a small shop, we can't carry everything all the time, but we can get everything under the sun."
Robertson has also capitalized on E-commerce. About 40 percent of the company's sales are through its website, www.speedinmotorsports.com.
He also offers to match any price customers find online.
"People like to buy online," he said. "We encourage people to buy online through us."
Speedin' Motorsports will also pick up and deliver bikes.
Robertson emphasized customer service, explaining that's why Speedin' Motorsports stays open until 7 p.m. and also opens on Mondays.
"We're open till 7 for the working man, so he can pick up, drop off, or whatever he needs done," he said.
The shop is tucked a block off Main Street in an under-utilized retail area behind a Wendy's.
A carpet store, greenhouse supplier and a pet care shop share the block.
For Robertson, Speedin' Motorsports builds on an underlying passion.
"What's not to like about sport bikes?" he said. "You're basically flying without leaving the ground. These machines are capable of extreme speeds, extreme handling, extreme fun."
Chuck Slothower can be reached at email@example.com; 505-564-4638. Follow him on Twitter @DTChuck.