Introduction
Some motorcycles have reached the position of a cult, like the RD series of Yamaha. From agile RD125 and RD135 to the cruel RD350, these two-stroke machines were born for adventure. Completed with light, mechanically simple, and a specific Ashwell, RDS became a symbol of speed and rebellion in the 1970s, 80s, and 90s. One component lies at the heart of the RD’s identity: its exhaust. Known in Portuguese-speaking motorcycle culture as the “escapamento RD,” this is not just a pipe for carrying gases out of the engine. It is the lifeblood of the two-stroke performance system — the secret behind the power band, the soundtrack of adrenaline, and a visual statement of style.
This article will dive deep into the world of RD exhausts: how they work, why they matter, the most popular aftermarket options, maintenance tips, and the passion they inspire among riders even decades after the bikes left showrooms.
Why the Exhaust Matters More on an RD
On a four-stroke motorcycle, the exhaust primarily evacuates gases and can alter the sound and a bit of midrange torque. On a two-stroke Yamaha RD, however, the exhaust is a critical performance component.
The RD’s exhaust uses what is called an expansion chamber. This uniquely shaped pipe manipulates pressure waves to “push” fresh air–fuel mixture back into the cylinder at precisely the right moment. Done correctly, it significantly boosts power output. Done poorly, it can kill the motor’s response.
In other words, the RD’s personality lives inside its exhaust. It determines whether the bike surges with explosive top-end or delivers a broad, usable midrange. It dictates how the bike sounds — raspy, hollow, metallic, or thunderous. To change the exhaust is to change the very soul of the RD.
Anatomy of the Expansion Chamber
An RD exhaust is not just a tube. It is a carefully engineered system with several zones:
- Header (or diffuser): The section that starts narrow at the cylinder and begins to expand. It reduces pressure, helping scavenge exhaust gases.
- Stomach (or middle-block): The widest part of the pipe, designed to resonate with pressure waves.
- Baffle Cone: The taping part that shows the pressure waves back towards the cylinder gives them time to push the fuel-hwa mixture in the combustion chamber.
- Silencer: Last section, often with fiberglass packing, which tames the noise and shapes the exhaust note.
This combination creates the famous “powerband” of two-strokes. Below a certain RPM, the bike may feel sluggish. But when the resonance kicks in, the RD surges forward like it has been hit by a wave of torque — a sensation that defines two-stroke riding.
Performance vs. Originality
When it comes to RD exhausts, riders often face a choice: preserve originality or chase performance.
- Original exhausts keep the bike authentic. For collectors restoring RD350s to showroom condition, factory exhausts (often heavy, painted steel with internal baffles) are essential. They deliver decent midrange, a mellow version of the RD’s trademark scream, and legal compliance in terms of noise.
- Aftermarket exhausts are a gateway to unleashed performance. Designed with light materials and tuned chambers, they can add noticeable horsepower and dramatically change the sound. However, they almost always require carburetor re-jetting to match new airflows. Without this adjustment, the bike takes the risk of lean and seizing.
The choice depends on the rider: Purist who loves Nostalgia, or performing seekers who want the most raw experience.
Famous Brands and Their Signatures
Dogster (Brazil)
Dogster specializes in stainless steel exhausts for RD135 and RD350 models. Their pipes are hand-made, often polished to a mirror shine, and engineered for balance. Some versions emphasize mid-to-high rev performance, making them a great choice for riders who use their RDs both on city streets and highways.
RR Tuned (Brazil)
A well-known name in Brazil’s RD community, RR Tuned offers multiple configurations for the RD350. Their GP-style exhaust routes both silencers on the right side, giving a race-replica look and shifting the powerband higher. Another design feature is embedded silencers, which blend style with durability. Their use of 304 stainless steel makes them long-lasting and visually striking.
Torbal (Classic Line)
Torbal focuses on retro authenticity. Their RD350 LC exhaust sets are crafted in carbon steel, available in black or chrome. They preserve the stock look and include internal silencers. For restorers who want to keep their machines period-correct, Torbal remains a trusted option.
Jollymoto and JL (Jim Lomas, Europe)
Internationally acclaimed, these brands build performance exhausts for Yamaha RD and RZ models. They are lighter than stock, often made in thin-gauge steel or stainless, and deliver race-ready power. Riders praise them for strong top-end gains and the intoxicating scream they produce.
Toomey Racing (USA)
A legendary name among Yamaha two-stroke fans, Toomey Racing exhausts are designed to maximize high-RPM power. While they may sacrifice a bit of low-end usability, they transform the RD into a track weapon. For enthusiasts who love the rush of the powerband, Toomey pipes are a badge of honor.
Comparing RD Exhaust Options
| Brand/Model | Focused RPM Range | Material | Visual Style | Rider Type |
| Dogster | Mid to High | Stainless Steel | Shiny, modern finish | Street + Sport |
| RR Tuned GP | Mid to High | Stainless 304 | Dual right silencers | Sporty, aggressive |
| RR Tuned Embedded | Broad/Mid | Stainless 304 | Hidden silencers | Style + durability |
| Torbal | Midrange | Carbon steel/chrome | Classic retro look | Restorers |
| Jollymoto/JL | High | Lightweight steel | Slim racing design | Track day enthusiasts |
| Toomey Racing | High | Lightweight alloys | Minimalist racing | Hardcore racers |
Maintenance of RD Exhausts
Two-strokes reward attentive owners, and the exhaust is no exception.
- Decarbonization: Oil residue builds up inside the expansion chamber, slowly restricting flow. Periodic cleaning (every 10–15,000 km) restores performance and sound.
- Silencer repacking: Many aftermarket silencers use fiberglass or ceramic wool. Over time, packing burns out, making the bike excessively loud and altering the backpressure. Repacking restores tone and function.
- Rust and corrosion control: Carbon steel exhaust must be painted or chrome to oppose rust. Stainless steel models are more durable but still polish is beneficial.
- Leak checks: Ensure tight seals at cylinder flanges and joints. Any leak robs performance and can leave oily residue on the bike.
The Sound That Defines the RD
If there is one thing that tilts RD Riders, then it is sound. A well -tuned escapmento RD exposes a metal, screaming exhaust note that makes in a pilgrimage in the form of tacometer mountains.
Enthusiasts describe it as addictive, almost musical. Videos of RD exhaust symphonies rack up views on YouTube and flood motorcycle forums. The sound isn’t just noise — it’s history echoing down the street, a soundtrack that transports veterans back to their youth and introduces newcomers to the magic of two-strokes.
Legal Considerations
While intoxicating, the RD’s sound can clash with modern noise regulations. Many regions enforce decibel limits, and open racing exhausts often exceed them. Riders should:
- Opt to the system with internal silencer or removable DB killers for road use.
- Check local laws to avoid fine or impoundments.
- Reserve open-pipe setup for track days or private programs.
Being mindful of noise laws ensures that RD riders can keep enjoying their bikes without attracting unwanted attention from authorities.
Is It Worth Upgrading?
The question many riders ask: Is investing in an aftermarket escapamento RD really worth it?
- Yes, if you crave performance. A good expansion chamber unlocks the RD’s full potential and transforms its behavior.
- Yes, if you love sound and style. Few upgrades change a bike’s character as dramatically as the exhaust.
- But it depends on your goals. Collectors and restorers may prefer stock systems to preserve value. Hardcore enthusiasts, on the other hand, often see aftermarket pipes as mandatory.
The RD is not just a motorcycle; it is a statement. And its exhaust is the boldest part of that statement.
Conclusion
The escapamento RD is far more than tubing and metal. It is a performance tool, a sonic weapon, and a cultural symbol. It shapes how the Yamaha RD rides, how it sounds, and how it is remembered.
Whether you choose the authenticity of Torbal, the shine of Dogster, the race focus of RR Tuned, or the raw shriek of Toomey and Jollymoto, you are not just buying horsepower — you are buying identity.
The RD era may have passed, but the legend of its exhaust continues to roar. And as long as two-stroke lovers keep polishing, repacking, and revving, the escapamento RD will never be silenced.
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