Discover everything about the escapamento rd. Learn about original and expansion chambers for Yamaha RD 135 and RD 350, performance tuning, and maintenance tips.
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Introduction
Talking about the escapamento rd is more than just discussing a mechanical part; it is an immersion into one of the most iconic chapters of two-stroke motorcycle culture. Whether for the legendary “Black Widow” (Yamaha RD 350LC) or the agile and beloved RD 135, the exhaust system is far more than a simple exit for burnt gases. In the world of two-stroke engines, the exhaust is the “lung” that defines the soul, the sound, and the power delivery of the machine.
In this comprehensive guide, we will explore the evolution of these exhaust systems, the technical nuances between original and performance models, and how you can extract the best performance from your Yamaha RD series through intelligent choices and proper maintenance.
The Physics of Power: Why the Exhaust Matters in 2-Stroke Engines
To understand the importance of the escapamento rd, one must first understand how a two-stroke engine breathes. Unlike four-stroke engines, where valves handle the intake and exhaust cycles, a two-stroke engine relies on pressure waves.
The bulbous shape of a performance escapamento rd is known as an expansion chamber. This chamber uses sound waves to pull spent gases out of the cylinder and, crucially, to push fresh air-fuel mixture back into the cylinder just before the exhaust port closes. This “supercharging” effect is what gives the RD series its famous “power band”—that sudden surge of acceleration that fans of the brand adore.
The Signature Sound
The metallic “ping-ping-ping” and the trail of blue smoke are trademarks of the era. A perfectly tuned escapamento rd produces a crisp, high-pitched sound that has resonated across generations of riders. It is a fundamental piece for anyone looking to restore a vintage bike to its former glory or prepare it for the track.
Comparison: Original vs. Performance (Dimensioned) Exhausts
For an RD owner, the first major decision is whether to maintain original aesthetics or seek modern performance gains. Below is a detailed comparison to help you navigate this choice.
| Feature | Original Exhaust (Silencer) | Performance (Expansion Chamber) |
|---|---|---|
| Primary Focus | Acoustic comfort and durability | Horsepower and torque gains |
| Common Materials | Black painted or chrome carbon steel | Stainless steel, Carbon steel, or “Cones” |
| Weight | Heavier due to internal baffles | Significantly lighter |
| Power Curve | Linear and predictable | Aggressive in mid-to-high RPMs |
| Maintenance | Requires periodic decarbonization | Requires repacking silencer wool |
| Aesthetics | Classic, factory-correct look | “Racing” style with visible welds |
Escapamento RD 135: Achieving Urban Balance
The Yamaha RD 135 is famous for being a “street warrior.” The ideal escapamento rd 135 needs to provide enough low-end torque so the bike doesn’t “bog down” at stoplights, while still allowing the engine to “clean out” and scream at high revs.
Popular Market Models for RD 135
In the Brazilian and international markets, several configurations have stood the test of time:
- Original/Silent Model: Perfect for those who value a stealthy ride and the classic factory silhouette for daily commuting.
- “S-Cut” Expansion Chambers: A very popular middle ground. These offer a performance boost without completely altering the bike’s side profile.
- Competition “Gomos” (Cones): These are artisanal exhausts made of multiple welded sections. They are designed for maximum flow at high RPMs, often sacrificing low-end comfort and quietness for raw speed.
Escapamento RD 350: Unleashing the Black Widow
The Yamaha RD 350LC is a masterpiece of engineering. With its YPVS (Yamaha Power Valve System), the exhaust works in tandem with a variable valve that regulates the exhaust port height. A poorly designed escapamento rd 350 can actually interfere with the YPVS, leading to “dead spots” in acceleration or a loss of top speed.
The Twin Pipe Design
Unlike modern sportbikes that often use a 2-into-1 system, the RD 350 traditionally retains a dual exhaust setup. Enthusiasts often look toward specialized brands like Dogster or Sarachú to replace the heavy stock units. These aftermarket systems significantly reduce the bike’s overall weight—one of the RD 350’s few Achilles’ heels—and allow the twin-cylinder engine to breathe with much less restriction.
Leading Brands and Manufacturers
The aftermarket industry for the RD line is incredibly rich. If you are searching for a high-quality escapamento rd, these brands are frequently cited by master mechanics and tuners:
- Dogster: Highly regarded for artisanal stainless steel fabrication and high-end performance, particularly for the RD 350.
- Sarachú: A legendary Brazilian brand from the 1990s that provides a deep, resonant sound and rugged durability.
- Wacs: Offers excellent value for money, often featuring aluminum silencers that look great on street builds.
- Rocket: Focused on extreme performance for modified engines, aiming for the highest possible horsepower figures.
Maintenance and Care for Your RD Exhaust
A common issue with two-stroke engines is “carbonization”—the buildup of carbon deposits inside the exhaust caused by the combustion of 2T oil. This obstructs gas flow and causes the engine to lose power over time.
Step-by-Step Cleaning and Preservation:
- Decarbonization: For original steel exhausts, specialized chemical cleaners can melt internal carbon. In extreme cases, professionals use a “blowtorch method” to burn out the deposits, followed by mechanical cleaning.
- Silencer Wool Replacement: If you use a performance escapamento rd with a removable silencer, remember to replace the fiberglass wool every 3,000 to 5,000 miles. This maintains the correct backpressure and prevents the sound from becoming too “tinny.”
- Corrosion Protection: Carbon steel exhausts should be cleaned with neutral soap and protected with a thin layer of high-temperature lubricant (like WD-40) after washing to prevent rust, especially around the header curves.
- Carburetor Jetting: This is the most critical step. Whenever you swap an original escapamento rd for a performance one, you must adjust the carburetor jetting (increase the main jet size). Failure to do so can cause the engine to run “lean,” leading to catastrophic piston seizure.
Frequently Asked Questions About RD Exhausts
1. Does installing a performance “escapamento rd” damage the engine? No, as long as the carburetor is properly jetted. The exhaust simply lets the engine breathe more efficiently; it’s the lack of fuel (running lean) that causes damage.
2. What is the sound difference between carbon steel and stainless steel? Stainless steel tends to produce a sharper, more “crisp” metallic ring, whereas carbon steel has a slightly deeper and more muffled tone.
3. Does the RD 125 exhaust fit the RD 135? Yes, the mounting points are identical. However, the internal volume of a dedicated escapamento rd 135 is slightly different to optimize the larger displacement.
4. How can I tell if my exhaust is clogged? The bike will struggle to reach high RPMs, the top speed will drop significantly, and the engine may run hotter than usual.
5. Can I paint my exhaust with regular spray paint? Absolutely not. You must use specialized high-temperature paint (rated for at least 600°C/1200°F), otherwise, the paint will bubble and peel within minutes.
6. Why does the RD 350 have two separate exhaust pipes? Since it is a parallel-twin engine with 180-degree firing, each cylinder requires its own expansion chamber to benefit from the pressure wave timing.
7. What is the difference between “High-Mount” and “Low-Mount” exhausts? This refers to the routing. High-mount pipes pass along the side of the bike (common on scrambler/trail styles), while low-mount pipes follow the traditional street bike line under the engine.
8. Does using synthetic 2T oil keep the exhaust cleaner? Yes. High-quality synthetic oils burn cleaner and leave significantly fewer carbon deposits compared to cheap mineral oils.
9. Is it legal to use a performance “escapamento rd” on the street? This depends entirely on your local regulations. Most performance exhausts exceed decibel limits for city use and may not have the required emissions certifications.
10. Where can I find original factory exhausts today? Authentic original parts are increasingly rare. They are usually found in “New Old Stock” (NOS) inventories or through specialized restorers, as Yamaha has long since discontinued production.
Conclusion: The Heartbeat of a Legend
Choosing the right escapamento rd is a journey that blends nostalgia with engineering. Whether you are restoring a “Black Widow” RD 350 to factory perfection or transforming an RD 135 into a street-legal rocket, the exhaust is the modification that yields the most immediate and satisfying results.
Always remember to prioritize reputable brands and never skip the carburetor tuning after installation. With the right care, the unmistakable roar of your RD will continue to echo through the streets for years to come, keeping the flame of the golden era of two-stroke engines alive.