Sean Skinner is the Jekyll and Hyde of custom motorcycles. Sometimes he builds tidy restomods that show restraint, and other times he builds idiosyncratic machines that put his imagination on full display. This sublime Yamaha RD350 street tracker sits somewhere in the middle.
Sean runs MotoRelic as a one-man band, out of a small garage behind his house in Hamilton, Virginia, USA. This project was commissioned by a customer who had picked up a 1973 Yamaha RD350 for $350 (a proper barn find) and wanted it turned into a street tracker.
“Normally, getting a bike for $1 per cc is a great deal,” says Sean. “But when he sent the photos, I felt like he overpaid. It was the crustiest, most forgotten bike I’d ever seen.”
“We had a laugh, and I told him ‘If it’s not locked up, then it will be great.’ His idea for the build would only require me to keep the frame and engine—everything else would go to the dumpster. He was prepared to spare no expense on this build, which made my job way more fun!”
“When the bike arrived, we had another laugh, but then got down to business talking about his dream. He wanted a lightweight road ripper with 19” wheels, true flat track Hoosier tires, a custom tail and seat, a tracker-style front plate, and a fire-breathing engine. He rolled out and I got to work, not knowing how the bike would evolve into what it is today.”
Sean started by yanking the Yamaha RD350’s motor out, boxing it up, and shipping it to vintage two-stroke specialist, Ed Toomey. “We discussed the client’s needs and nailed down a proper list of things that Ed would do to this little powerhouse,” he tells us. “I then proceeded to order a pile of goodies for the build.”
With the bare frame on the workbench, Sean set about putting together a trick new rolling chassis. The front-end wears a set of Suzuki GSX-R750 forks, gripped by Cognito Moto yokes. Cognito supplied the 19” wheels too, matching Excel rims to their proprietary hubs.
The upgraded wheels included a rear brake disc conversion, so Sean installed a Brembo caliper and designed a new brake pedal assembly and master cylinder mount to actuate it. “Since there was a Brembo on the rear, the customer felt like the front needed to match,” he adds. “Goodbye Tokico, hello Brembos! Who am I to argue?”
Sean’s plans for the back end of the RD350 involved a mono-shock conversion, but then his customer sourced an aluminum from Trac Dynamics. Built with a two-inch stretch, the new twin-shock swingarm left plenty of room for the 19” rear wheel. A pair of HyperPro shocks was installed to complete the setup.
“With the chassis now in roller form, I got to work designing how I wanted the bike to look,” says Sean. “I had a Honda Ascot tank that really screamed ‘tracker,’ but it was fairly wide for this skinny lady. I decided the side profile was perfect, so I cut the tank in half, narrowed it two inches, and fabricated all the mounts to make it fit the frame.”
“The tank has an interesting shape on top with different angular panels, so I wanted to let that flow back to the tail. I shaped the tail section out of aluminum to match the top of the tank, and gave it some style down the sides. The frame then received all the mounting tabs to hold it all in place.”
“Honda added a recessed area to the back of the Ascot tank for their factory seat. I used that area to shape my seat design, allowing a seamless flow from tank to tail. Counterbalance Cycles stitched up the rich brown leather.”
The RD350’s modified bodywork left no room for the OEM side covers, one of which doubles up as an oil tank for the Yamaha two-stroke’s ‘Autolube’ oil injection system. To replace it, Sean fabricated an ultra-slim reservoir that takes a quart of oil and doubles up as a rear inner fender. An externally mounted tube shows the oil level.
There were smaller tasks on the bike that required equally creative solutions. Sean wanted to fit grippy enduro footpegs to the RD350, but didn’t want to lose the OEM rubber footpeg mounts. So he modified them to adopt the modern pegs instead.
More of Sean’s tidy metalwork can be seen up front, where a number board-style headlight nacelle houses an Eagle Lights LED and a Motogadget Chronoclassic speedo. Just behind it are ProTaper risers and bars, fitted with Motogadget switches, grips, bar-end turn signals, and mirrors (which were removed for these photos).
The aging RD350’s wiring was binned too, in favor of a new loom and a Motogadget mo.unit brain. Spiegler Performance supplied the Motogadget bits, along with a tiny Kellermann LED taillight.
With the build approaching the finish line, Sean called on Danny Knight at Knight’s Kustoms to lay down a livery that’s out of this world. Using Yamaha’s traditional blue, yellow, and black palette, the design is a reinterpretation of classic RD350 graphics.
Finally, Sean treated the iconic two-stroke to a coveted Jim Lomas stainless steel exhaust system, which he was lucky enough to find at Economy Cycle. All that was left to do, was find out how well the freshly-rebuilt engine would perform…
“Once the beast of an engine came back from Ed Toomey, the bike was ready to rip—and rip it does,” says Sean. “First gear is a serious handful. At 6,000 rpm, the fully ported engine breathing through 28 mm Keihin PWK carbs gets on the pipe and lofts the front wheel with some serious aggression. Second is no different—while staying on the pipe she screams to life making you feel like the bike is trying to toss you off the back.”
“It’s smiles for miles while tearing up the back roads. The sound out of those JL pipes is better than any symphony at the Sydney Opera House. Combined with the smell of 100 octane low lead airplane fuel, it feeds all the senses while you’re trying to handle the reins of this wild horse. Damn good times!”
MotoRelic | Instagram | Images by Jonathan Thorpe
