Bolt Motor Co. builds a 500cc weapon…
The Yamaha RD350 is one of the most iconic sporting motorcycles ever produced. The original air-cooled 350cc two-stroke parallel-twin was produced from 1973-1975, and the RD quickly became a darling of club racers around the world. It earned a reputation as a giant-killer capable of embarrassing much larger four-strokes and could pull away from all but the fastest muscle cars of the era…at a retail price of just $839.
The RD350 returned in the 1980s as a liquid-cooled model, first as the RD350LC and then as the bike known alternatively as the RD350LC II, RD350 YPVS, or RZ350 (here in North America), which boasted Yamaha’s new power-valve technology. The bike out-turned, out-braked, and even out-accelerated many of the big-bore superbikes — at half the price.
“A lightweight, repli-racer sport machine… Within that narrow scope, the RZ350 is so good, so right. You know what the bike was built to do the instant you lay eyes on it.” –Cycle World, 1984
While the 350cc RD/RZ was burning up the local streets and circuits, Yamaha’s YZR500 V4 was making a name for itself in the 500cc premier class of the Grand Prix World Championship, earning victories and championships with riders like Kenny Roberts, Eddie Lawson, and Wayne Rainey.
The bike you see here is a tribute to those heady 500cc days, built by our friends at Bolt Motor Co. of Spain:
“The client literally brought the bike disassembled in two boxes… He wanted an old-school race-customer version, paying tribute to the Yamaha 500s from the glorious 2-stroke years, and more specifically to Wayne Rainey.”
We featured Bolt’s Yamaha RD350 YPVS “Gulf Special” a couple of years ago, but this RD build takes things to a whole new level. Highlights include a Yamaha R6 front end / swingarm / wheels, Brembo brakes, modern electronics and lighting, custom bodywork and paint, and what they call the main course: a fully rebuilt engine with a 500cc big-bore kit!
Yes, this Bolt-built RD is now packing 500cc’s worth of punch from the liquid-cooled power-valve twin — talk about a giant-slayer! And, as you can see, they aren’t shy of putting it through its paces on the track.
Below, the Bolt team gives us the full rundown of the build, and photography credits go to Mario Rodrigo Martín.
500cc Yamaha Restomod: In the Builder’s Words…
It’s a project that excites us a lot because of how iconic the model is, the famous Yamaha RD350, an exclusive work on which to carry out the transformation. It’s a bike that was produced in various versions, and the customization done is very special.
The client literally brought the bike disassembled in two boxes, and it was an arduous task of assembling it first, followed by sourcing parts. The first step was to assemble the entire bike to begin the design process. The client wanted an old-school race-customer version, paying tribute to the Yamaha 500s from the glorious 2-stroke years, and more specifically to Wayne Rainey.
The client gave us a very detailed and extensive briefing, but at the same time allowed us to advise him and gave us freedom to carry out our proposal. The MAIN COURSE: fitting a 500cc power kit!!!
We started by dissecting the bike. The client wanted very powerful braking and safe handling. To achieve this, we fitted the entire front end from a Yamaha R6.
We added a powerful braking system with oversized discs, Brembo master cylinder, and Brembo calipers, giving this classic an exceptional performance.
We assembled the rest of the components in our workshop (forks, triple clamps, calipers, discs, wheel axle, steering stem, etc.), performing a meticulous job with very satisfactory results.
We installed Rizoma clip-ons, Biltwell grips, and Motogadget turn signals in the grips, along with some sublime mirrors from the German brand Highsider, all combined with new controls and a very old-school look, plus a digital-analog instrument cluster and a minimalist Koso temperature gauge.
We added a modern LED headlight with a neo-retro design on our custom 3D-printed headlight mask, featuring a sober and elegant design that profiles the silhouette of the bike.
The upper part of the bike was handled with great care. The paint was a brilliant choice, proposed by the client. It’s a tribute to the brand and the 500cc bikes from the legendary races of the 90s.
The seat, completely handcrafted, was made from weatherproof suede with embroidery that matches the colors of the tank and covers, the latter featuring a tail from the first-generation Yamaha RD, giving it a very cool and wild look.
In terms of electrics, we modified the electronics mapping to adjust the engine’s performance. The entire installation was done by our engineers, who have extensive experience in the racing world. The wiring was fully renewed with high-performance cabling, finishing the job by fully programming all the functions in the instrument cluster.
Mechanically, the entire engine was restored. Our mechanics carried out a complete engine overhaul, including major work: cylinders, pistons, crankshaft, reeds were replaced, and we installed a high-performance 500cc kit.
It was an exhaustive job to extract the maximum performance from the powerful engine, tuning the carburetion and installing custom-made Turbokit exhausts.
For the wheels, we opted for Yamaha R6 rims, achieving a very racing look, which the client greatly appreciated. The ventilated and wave discs are the aforementioned Brembos. In the rear, we fitted a Yamaha R6 swingarm, allowing us to install a 170 tire, and we designed the sprocket and chainring in our 3D design department to ensure perfect alignment.
The clutch and brake levers are the latest generation Nissin, top-quality components in line with everything done on this unique customization.
A very special BOLT with a high level of craftsmanship, quality, and refinement, with which we’ve aimed to take this project to another level.
Follow the Builder
- Website: www.boltracer.com
- Instagram @boltmotorcompany
- Facebook: boltmotorcompany
- Photography: Mario Rodrigo Martín
Perfect bike, perfect job. It must be – for ride – brutal combination of weight, power and two stroke bad manners. It will be interesting information about HP, but I think that “enough”.
What a wonderfully specced, evocative bike. I knew the 350s could be stretched to 400-ish ccs, had no clue that 500 was possible. Bravo!
2 stroke! Cool. Maybe Bolts best looking effort yet.
Çhe dire rivisitazioni in chiave odierna di mostri sacri di quei tempi..da me conosciuti.👍💪🖐 Beppone
Great looking bike, but I’m interested in what parts were used to obtain 500 cc capacity, what changed to the reed valve and carbs . Also how much power was obtained please
How do they get 500cc out of the Athena banshee barrels. Athena’s are 390cc with a stock crank and 410cc with a 4mm stroker crank.
I had a 1976 RD400 and I got to ride the rare OSSA 500 street twin (loved that bike). Back then and since I’ve thought many times “If only they had made a 500cc RD!” Now someone has. To me combining the best of all that seems to be a no brainer and must be a great bike. I’m jealous.