Introduction

Few parts are more important than the escapamento RD (RD exhaust) when it comes to optimizing the Yamaha RD motorcycle’s performance, sound, and authenticity. For fans of this legendary 2-stroke series, particularly vintage models like the RD 125, RD 135, or RD 350, the exhaust is more than simply a component; it’s a performance indicator and among the first changes riders think about when adjusting the engine’s behavior.

However, not all exhaust is made equally. A thorough understanding of backpressure, expansion chambers, materials, and general tuning objectives is necessary when selecting or constructing the ideal escapamento RD. This thorough book covers everything you need to know, whether you’re restoring a classic RD or upgrading for daily performance, racing, or street use.

You will discover the effects of escapamentos on noise levels, torque curves, engine output, and even longevity. In order to assist RD riders in making the best decision, we will also examine the changing aftermarket landscape in Brazil and throughout the world, contrasting the best manufacturers, configurations, prices, and user experiences.

What Is an Escapamento RD, and Why Does It Matter?

The exhaust system made for Yamaha’s RD-series motorbikes, a renowned line of two-stroke bikes that are well-liked in Brazil, Europe, and other countries, is especially referred to as the “escapamento RD.”

The harsh tone, rapid throttle response, and explosive power delivery of the RD 125, RD 135, and RD 350 in particular are characteristics that are primarily influenced by their exhaust systems.

Why It Is Important

• regulates the scavenging of burned gases.
• affects the behavior of the powerband
• controls the backpressure in engines.
• forms the sound profile, which is a fundamental component of RD’s identity.

Essentially, the proper RD exhaust adds that distinctive 2-stroke snarl while improving engine longevity, responsiveness, and efficiency.

Types of RD Exhausts: Original vs. Performance vs. Custom

Selecting an RD exhaust requires striking a balance between originality, cost, and performance.

Comparison Table: RD Exhaust Types

 

Type	Description	Pros	Cons
Original (OEM)	Factory exhausts from Yamaha or approved vendors	Authentic, street-legal	Heavy, limited power
Performance	Aftermarket tuned pipes for more power	Lightweight, optimized HP	Louder, may be illegal
Custom	Hand-fabricated systems for specific needs	Fully configurable	Expensive, hard to tune

OEMs maintain low-end torque for street use, whereas performance exhausts frequently increase the powerband higher (excellent for racing).

How Exhaust Systems Affect 2-Stroke Engine Performance

In contrast to 4-stroke engines, 2-stroke engines mainly rely on exhaust design to increase cylinder pressure through wave reflection and evacuate exhaust gases. Key functions include improving horsepower at specific rev ranges, enhancing scavenging using pressure waves, influencing throttle feel based on resonance, and causing boggy low-end performance, excessive smoke, and shorter piston/ring life due to poor exhaust matching.

Performance Gains: Before vs. After Upgrade

 

RD Model	OEM HP	Performance Exhaust HP	Approx. Gain (%)
RD 135	18 HP	21–23 HP	+18% to +28%
RD 350 YPVS	55 HP	60–65 HP	+10–18%

(Source: Brazilian performance shops’ dyno tests, 2023)

Expansion Chambers Explained: Magic Behind the Curve

The expansion chamber is the secret to most high-end 2-stroke performance, especially for RD bikes.

How It Operates:

Power is increased when the chamber pushes the unburned air-fuel mixture back into the combustion chamber by reflecting pressure waves into the cylinder at precisely the proper moment.

Important Sections of an Expansion Chamber:

• Header (which attaches to the cylinder)
• Cone that diverges (lowers pressure)
• Converging cone (pushes wave back) and belly (holds volume and wave)

It’s crucial that this form matches your engine RPM goal. The majority of aftermarket RD pipes are high-rev (8,000–10,000 RPM) tuned.

Key Components in a Quality Escapamento RD

What makes an excellent RD exhaust different from a good one? It’s the materials and craftsmanship.

Key characteristics:

• Clean airflow is ensured by mandrel-bent tubing.
• Weld accuracy: avoids limitations on interior airflow
• Detachable silencers: For controlling noise and tuning
• Ceramic or nickel-chrome coating: To stop rust

 

Material	Benefits	Drawbacks
Mild Steel	Affordable, easy to weld	Rusts easily
Stainless Steel	Durable, high-temperature resistant	Heavier, pricier
Titanium	Ultra-lightweight, corrosion-proof	Very expensive

Stainless steel strikes a balance between cost and functionality for usage on roads.

Top Aftermarket Escapamento Brands for the RD Series

Performance exhaust systems for RD bikes are produced by a number of reputable brands. Here are a few of the more reputable names:

Top Brands Comparison

 

Brand	Known For	Availability in Brazil
FortG	Handmade RD 135 exhausts	Very Popular 🇧🇷
Pro Tork	Affordable performance pipes	Widely available
JJ Escapamentos	Custom-shaped tuned pipes	Specialized, premium
JollyMoto	High-end European 2-stroke pipes	Imported, pricey

Always buy from approved retailers or authorized dealers to steer clear of poor-quality knockoffs.

 Escapamento RD: Sound, Legal Limits & Street Regulation

Many riders fail to check local emissions and noise restrictions, which can result in penalties or failed inspections.

For instance, in Brazil:

• Motorcycles typically have a decibel limit of 99 dB.
• Without DB-killers, aftermarket pipes may surpass regulatory restrictions.
• Newer emission regulations may not apply to older RD models.

Sound Comparison (Approximate dB Levels)

 

Exhaust Type	Idle dB	Revving dB
OEM RD 135	70	88
FortG Tuned Pipe	78	102
JollyMoto Racing Pipe	82	106

When riding in crowded or metropolitan locations, add a suppressor or DB-killer insert.

Custom-Built vs. Factory-Tuned: Which One is Right for You?

Although it is alluring, going custom necessitates extensive knowledge or speaking with a tuning specialist.

Benefits of Custom-Built Exhaust:

• fits your RPM and riding style.
• tailored to particular fuel configurations
• Unmatched craftsmanship

Think about if:

• You’re creating a show bike or racing it.
• You operate a customized piston/carbohydrate system.
• You detest compromises made by factories.

A pre-tuned FortG or Pro Tork pipe, however, can provide 80% of the advantages with 0% of the danger for recreational riders.

Installation Tips & Maintenance Best Practices

For long-term performance and engine safety, your Escapamento RD must be fitted properly.

Steps for Installation:

1. Take out your old exhaust by using the proper sockets.
2. Apply a temperature-resistant sealant after cleaning the exhaust port.
3. Gently align with the brackets before tightening.
4. Before starting the bike, test-fit it.
5. Look for vibrations or exhaust leaks.

Checklist for Maintenance: 

Clean up after rainy rides.

Every 2,500 kilometers, remove carbon deposits from the silencer. Every month, check the brackets and springs for stress cracks.

More than 4-stroke systems, 2-stroke exhausts are impacted by heat cycles, vibration, and road grime.

Common Mistakes to Avoid in RD Exhaust Upgrades

When working on the exhaust of your RD, stay away from these pitfalls:

• Disregarding jetting modifications: Carb tuning is required with a new pipe.
• Selecting large, noisy pipes: It’s not always preferable to ride on the street.

Incorrect mounting causes exhaust leaks or fractures.

Ignoring tuning completely results in performance that is inferior to OEM.

Always use plug chops and sound tests to test tuning changes, and if at all possible, take air-fuel meters into consideration.

FAQs

 Does the Escapamento RD require tweaking, or is it plug-and-play?

For best results, carb re-jetting is necessary for the majority of performance pipes.

Is it possible to utilize an RD 135 escapamento on an RD 125?

Ports, lengths, and tuning vary; thus, it is not advised.

Do modified RD exhausts have legal ramifications in Brazil?

Yes, there may be fines for breaching noise and emission limitations.

How frequently should the expansion chamber or silencer be cleaned?

Every 2,000–3,000 kilometers when used normally.

Will my engine eventually be ruined by a racing pipe?

Not if it’s maintained, re-jetted, and calibrated correctly.

Conclusion

The Escapamento RD is a fundamental performance component that influences the way your RD sounds, pulls, and rides. It is much more than just a metal pipe. Knowing how exhaust systems work with your 2-stroke engine provides you power, control, and the enjoyment of riding, regardless of whether you go with a performance-tuned pipe like FortG, stay true to the OEM for authenticity, or go completely custom.

In order for your Yamaha RD to sound and run like the beast it was designed to be, this article provides a tried-and-true blueprint for selecting and maintaining the proper exhaust for enthusiasts, builders, and new RD owners.