#Dynomite Moto

[motocrunch]

[olivereliott]

Chopper Rescue: A Honda CB900 revived by Purpose Built

We don’t usually go in for choppers around here—but we do appreciate the skill and effort that goes into building a truly stellar chop job. And Tom Gilroy at Purpose Built Moto on Australia’s Gold Coast gets it too.

The PBM portfolio is stacked with cafe racers and scramblers, but that didn’t stop them from tackling a chopper…and knocking it out the park. “The skills are the same,” says Tom, “and I love the style just as much—it’s just a different thought process.”

Purpose Built worked with an unusual donor bike for this project: a Honda CB900. And one that came with its own baggage, too.

The shop’s client had bought it wrecked, ten years ago, and decided to have it rebuilt as a chopper. He originally found a builder on the Sunshine Coast—but the work took literally years to complete, and the bike looked horrible and didn’t run right.

“He was never happy with it,” Tom tells us, “which, after waiting so long, is understandably a kick in the guts. One thing I will say, is that the frame that was build from scratch was very well fabricated, an amazing job.”

PBM decided to build their own take on a Japanese chopper: “Something the owner would be proud to ride and show off to his mates.” So they stripped the bike down, ripped out the dodgy wiring and got cracking.

First on the agenda was the CB’s stance. Tom and co. kept the 17” rear wheel the bike had come with, but re-laced the front hub onto a 21” rim. Both are wrapped in Avon Cobra tires.

Since the Honda’s frame had been done well the first time around, Tom focused his energy purely on rebuilding the rear section. “This whole process was foreign to me,” he says. “A new set of geometry dynamics to work with, to achieve a good and solid chopper look.”

A new subframe was fabricated using 28 mm Chromoly tube, and a pair of new shock mount spigots turned up. Then the swing-arm was shorted about 50 mm to tuck the rear end even more. Finally, Purpose Built mounted up a set of shrouded 10” shocks, from Ride Dynamics.

Next up, the crew turned their attention to the bodywork. The CB had come with a huge mustang chopper tank—but Tom thankfully swapped it out for a Honda CB750 K2 unit. “It fitted with my ideas for the bike, and it allowed the huge engine to protrude from under the tank,” he explains.

Then came the trickiest part: getting the balance of the seat, rear fender and sissy bar just right. Tom started with a lipped rear fender, then bent up some bar with a trio of curved ends that match the fender’s lip. The arrangement was finished off with a prototype tail light that’ll be joining Purpose Built’s extensive parts catalog soon.

Tom then whipped up a new seat pan and electrics tray, and shaped up the foam. Jamo at Timeless Autotrim kicked out a sublime nubuck leather cover, with pleats that run all the way over the back of the seat.

Up front, Tom designed a vintage style top yoke, taking inspiration from vintage Ceriani parts. That design was then CNC cut and polished up, and now holds a set of narrowed 1” mini-apes.

Purpose Built usually focus on simple and clean results on their cafe racer builds. But for this bike, Tom deliberately wanted to add some flair. “For a chopper, I’m thinking, ‘What is the best looking, and most elaborate way, to get this job done?’”

A lot of this approach translated into the Honda’s intricate new headlight mount. Tom bent up a set of rods that flow up over the yokes, and end in a ducktail that matches the sissy bar’s. The arrangement holds two 4.5” Purpose Built headlights.

The detail work on this chop-job could fill volumes. The cockpit features leather wrap grips, modern Purpose Built switches with internal wiring, and reverse levers with a cable operated master brake cylinder hidden under the fuel tank. And there’s a whole bunch of smaller brass parts scattered throughout the bike.

The horrid exhaust has been ditched too. In its place is a four-into-four system with straight through cans, finished with turned brass end caps. “It’s obnoxious and loud,” admits Tom.

The engine was cleaned up and refinished in black with some mild polishing in places, and treated to a set of Keihin CR carbs with DNA filters. Then the whole setup was run and tuned by the team at Dynomite—so it runs like a dream now.

Tom admits that this bike doesn’t corner as hard as PBM bikes normally do, but it’s still a joy to ride.

“Something I hadn’t understood until now was the allure of riding a chopper. I’ve always loved winding roads, fast paced corners and a bike that handles great. But on this bike, it doesn’t matter where you’re riding, it’s about what you’re riding.”

It also doesn’t hurt that the paint job is flawless. Tom chose red as a nod to the original CB900, then Justin at Popbang Classics laid it down with a deep candy finish, and gold leaf accents.

Not surprisingly, Purpose Built’s client is over the moon with his revived chopper. But more than that, Tom is stoked that someone trusted him enough to step outside of his own comfort zone.

Purpose Built Moto | Facebook | Instagram | Images by Made Social

[olivereliott]

A Triumph sidecar built to deliver cold brew coffee

We love sidecars, but they’re usually sedate rather than sporty. And a classic café racer with a chair? That’s even more rare.

So we love the look of this most unusual combination from sunny Queensland in Australia. The ‘Cold Brew Cafe Racer’ comes from Tom Gilroy of Purpose Built Moto, and it’s built around a Triumph Scrambler.

The project started like many others: A couple of blokes meeting up for a beer at their local haunt. Tom’s favorite spot is the iconic Sandbar restaurant in Surfers Paradise, on the famed Gold Coast stretch of Queensland.

“I rolled up on my GS550 to see my mates Jake and Rich, who threw an idea my way,” Tom recalls. Jake’s family own the Sandbar, and the idea was to build a sidecar rig to deliver Vittoria Cold Brew Coffee to the coastal community.

A deal was done: Tom would build the rig as a creative collaboration with the coffee company and the restaurant. And all agreed that the bike had to perform with and without the sidecar.

“When it’s not delivering a morning boost to Gold Coast residents out walking their trophy dogs, it has to handle a fast-paced Sunday afternoon run over the mountains!” says Tom.

The donor was a 2009 Triumph Scrambler, with the air cooled 865cc parallel twin—and a 270-degree firing interval for that famous exhaust note. A Cozy sidecar would be attached, mimicking the style of the vintage Steib 350 and 500 series sidecars.

“I was glad to do something different with a Triumph,” says Tom. “They’re such a staple for custom builders—and with a sea of bolt-on parts available, it’s easy to blend into the crowd.”

Tom wanted a timeless look that never grows old: “A bit like a vintage Rolex.” While he set to work on the bike, he sent the sidecar body to a friend for a cleanup.

The brakes and suspension were top of the to-do list. Tom’s given the Scrambler hefty 54mm polished USD forks and twin disc brakes from a Triumph Tiger, and a custom triple clamp. He’s also lowered the forks 40mm and rebuilt them to suit the ride height with the sidecar attached.

The rear suspension was treated to a set of all new K-Tech Bullit shocks, a spring-less system that offers an incredible ride. (“I was a little apprehensive on this one but the product over-delivered and presents a really tidy finish.”)

New wheels were the next big ticket item: specially machined alloy soft lip rims, 17” x 3.5” at the front and 17” x 5.50” at the back, laced up to the existing hubs. The massive rear wheel was wrapped in Shinko Stealth 003 rubber and required sprocket offsets to fit.

Up top, Tom’s built a short, hooped tail with a flowing cowl and integrated lighting. And since the color scheme was to be white with metallic highlights, he decided to integrate a few touches of brass into the design. “But you have to be careful,” he acknowledges. “It’s easy to go overboard with such details.”

Look closely at the tank, and you’ll notice a subtle raised edge following the top line. “I’ve seen a lot of chopper builders using round or flat bar to add a 3D aspect to the tank design,” Tom explains. “I like the concept, so I’ve adapted it to this café racer design with 6mm solid brass rod, hand-shaped and welded to the tank and tail sections.”

TIG welding brass to mild steel wasn’t the easiest feat, but after a few runs and stuff-ups, Tom got the hang of it. And then he added other brass details like custom-turned EFI choke and idle controls, EFI caps and a billet brass fuel cap.

The final piece to finish off the silhouette was the front cowl, which is a 2017 Thruxton piece—modified to fit the front end, and housing custom PBM Speedhut gauges. Clip on bars are finished with new levers and PBM’s own minimalist button switches. The Tarrozzi rearsets are a very neat upgrade too, because Tom has repositioned the master directly above the right foot brake, eliminating the need for a clunky linkage.

Tom has been dabbling in building exhaust headers, so he was determined to craft one for the Triumph in-house. He’s used a single sided 2-1 design with the collector placed just before the muffler—so the headers could frame the triangular stator covers. “When you hear it fire up [in the video below] you’ll see why we all love it so much!” says Tom.

Marios at DNA Performance Filters made a one-off set of custom brass filters, laser etched with a PBM logo. “Paired with the color-matched EFI body, brass caps and polished bowl (albeit a fake one) they look incredible. Most importantly, when on the tuning bench at Dynomite Moto they opened this torquey Triumph motor nicely.”

Tom gave the Triumph to his friend Jake for a shakedown run, minus the chair, on the Distinguished Gentleman’s Ride. “While he was out testing the bike, I was in the shop tinkering away on the sidecar.”

Tom pushed the sidecar opening back 400mm to achieve a bullet shape, and braced and hinged the body. This allowed room for a custom-built cooler to serve the bottles of cold brew.

He also trimmed down the fender and installed new mounts, so the fender now moves with the wheel and hugs it tightly for a cleaner look. Extra lighting went in: a PBM 4.5“ LED headlight and a twin stack of prototype PBM Orbit Mini LED brake lights at the back.

New brass rods shaped onto the sidecar body match the highlights on the bike, and there’s new upholstery inside—coffee brown leather and stitching.

The final piece of the puzzle was the intricate sidecar alignment. “Having read through a few manuals on geometry and functionality, I figured I needed some advice from those who had done it before me,” Tom admits.

“The answer was to set up some straight edges and calculate three key running factors—the toe-in, lean-out and axle lead. It took me a few rounds of fine-tuning.”

Tom reckons that riding the Triumph without the sidecar is an equally pleasurable experience, thanks to the suspension mods, dyno tuning and bellowing 2-1 exhaust.

“Due to the quite weighty sidecar mounts, the bike alone isn’t the nimblest performer—but you can have the time of your life leaning into some nice mountain corners, with power on tap at a slight twist of the wrist.”

Sounds like the best of both worlds to us. We’ll drink to that.

Purpose Built Moto | Facebook | Instagram | Images by Nathan Duff | Video by Electric Bubble