Since dawn In Grand Prix motorcycle racing, the 125cc class has served as a testing ground for factories and riders alike, creating crazy racing and memorable machines. The 250cc Moto3 class replaced the classic 125cc class 12 years ago, but the ‘starter’ series of Grand Prix racing continues to provide the thrill—and a glimpse of the MotoGP superstars in future.
This Sym The Wolf 125 pays homage to the golden age of 125cc GP racing. It’s the work of Eric Ku—a Taiwanese custom car builder who works under the moniker FirstRider Custom and loves classic race cars.
“I have a strong passion for 1960s racing, especially as a Honda enthusiast,” he told us. “I aspired to create my own classic racing motorcycle, envisioning myself speeding around the track. I also imagined the designs I would make as a designer at that time to help riders win championships.”
In stock form, the SYM Wolf 125 is a modest commuter — albeit an incredibly popular one in its home country. But Eric’s Wolf is unrecognizable. Taking on all the work himself, except for the paint job, he put a lot of effort into transforming the car into a modern take on iconic classics like the Honda RC143.
Eric confirmed: “The overall design is inspired by Honda’s RC series. “I adjusted the body proportions to suit my body shape, including leg room and chin space. The tail section incorporates a number of modern elements similar to the fixed-wing structure commonly found on today’s MotoGP bikes, blending classic and modern aesthetics.”
Working from the inside out, Eric bored the Wolf’s 56.5mm cylinder to 67mm, stuffed a larger piston in, and built a custom crankshaft with a longer stroke. That bumped the engine up to about 247 cc, with a 5-speed transmission replacing the OEM 4-speed. A reinforced clutch and upgraded oil cooler have been added to maintain performance and reliability.
Eric also replaced the cylinder head with a modified unit that has two exhaust ports. It now uses larger intake and exhaust valves, with a Keihin PWK36 carburetor mounted on a custom alloy intake that orients it sideways, as that’s the only way it will fit. “I crafted a direct intake port, which not only enhances performance but also creates a striking visual impact on the overall appearance,” adds Eric.
The carburetor draws air through a large velocity tube through the fairing. Gas exits through an asymmetrical twin exhaust system. One of the mufflers protrudes from the body on the top left, while the other runs along the bottom of the bike on the right.
SYM’s windshield and fuel tank are discrete recreations of the Honda RC143 bodywork. Not only did Eric shape the fiberglass fairing by hand, but he also went so far as to create his own acrylic windshield—a challenging process with many failures. The simple rectangular headlights sit behind the front protective grille.
The low steering clamp sits behind the fairing, equipped with retracted controls and classic white grips. A particularly interesting touch is how the custom wind deflectors are integrated with the speedometer housing.
The steel tail follows a less traditional design. Featuring a clamshell design with deep grooves, it hugs the contoured 3D printed taillights. At the bottom, an open battery tray gives the raw feel of a race bike while keeping things tidy.
Underneath the bodywork, Eric freed the frame of all unnecessary mounting tabs, before welding in extensions to place the footpegs in the optimal position. The bike now rolls on 18-inch DID rims, with a modified Yamaha SR150 drum brake hub up front. (Eric’s handcrafted front brake air hose is another attractive detail.)
Eric chose blue and white for his SYM Wolf racing livery, not because of any particular historic motorcycle but because those are his favorite colors. This combination suits this bike perfectly, with a white finish on the frame and fork for emphasis.
But perhaps this project’s greatest success is how it encapsulates the era that inspired it. If we didn’t know better, we would think that the photos of Eric riding his Wolf on the track were taken in the 60s.
