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  3. YAMAHA 4EX-21101-00-UJ

YAMAHA 4EX-21101-00-UJ Frame Chassis

fits model: Yz125, Yz, 125. make: Yamaha. year: 1993.

4ex-21101-00-uj Yamaha 1993 93 Yz125 Yz 125 Main And Subframe Frame Chassis

( Manufacturer Part Number: 4EX-21101-00-UJ ), ( Part Type: Frame ), ( Country Of Origin: Japan )

Review YAMAHA Main And Subframe Frame Chassis fits YZ125 YZ 125 1993

The **Yamaha YZ125 1993 model (Frame/Chassis: 4EX-21101-00-UJ)** is a classic example of Yamaha s legendary 125cc dirt bike engineering, designed to deliver a perfect blend of performance, durability, and rider engagement for both beginners and seasoned enthusiasts. This frame and chassis set, originally part of the YZ125 s iconic air-cooled, single-cylinder powerplant, embodies the timeless simplicity and robustness that defined Yamaha s dominance in motocross during the early 1990s. Crafted from high-grade steel, the frame features a **double-cradle design** with a reinforced backbone and downtube construction, ensuring exceptional rigidity while absorbing the brutal impacts of off-road riding. The **4EX-21101-00-UJ** designation indicates a specific variant of the frame, likely optimized for the YZ125 s signature balance of lightweight agility and structural integrity, allowing riders to navigate tight corners, jump obstacles, and maintain control at high speeds with precision.

The chassis itself is a masterclass in functional aesthetics, with clean, aerodynamic lines that reduce wind resistance while maintaining a compact footprint for easy maneuverability. The **aluminum swingarm** (common in later YZ125 models) or steel swingarm (depending on the exact build year) pairs seamlessly with the frame, providing a stable platform for the rear suspension a **pro-link system** that offers progressive damping and adjustable preload to handle the roughest terrain. The **steel fork legs** (if part of the original setup) are known for their durability and straightforward maintenance, though modern upgrades like WP or Showa forks are often retrofitted for enhanced performance. The **wheelbase** is optimized for quick turning, while the **seat height** (typically around 36 inches) ensures accessibility for riders of varying heights, making it an ideal choice for youth or smaller riders looking to develop their skills without sacrificing control.

Underneath the frame lies the **Yamaha YZ125 s legendary air-cooled, single-cylinder engine**, a powerhouse known for its smooth revving characteristics and reliable performance. The **4EX-21101-00-UJ** frame is designed to accommodate this engine s compact yet powerful layout, with precise mounting points for the cylinder, crankcase, and transmission. The **clutch and primary drive system** are engineered for smooth engagement, allowing riders to transition seamlessly between gears, while the **final drive** (typically a chain) delivers power to the rear wheel with minimal slippage. The frame s **subframe** integrates neatly with the fuel tank and handlebar assembly, creating a cohesive riding position that promotes comfort during long sessions on the track or trail.

For collectors, restorers, or riders seeking a no-frills, high-performance dirt bike experience, the **1993 Yamaha YZ125 frame/chassis (4EX-21101-00-UJ)** offers a rare opportunity to own a piece of motocross history. Whether used as a standalone frame for a custom build or paired with an original or upgraded engine and suspension, this component is a testament to Yamaha s engineering prowess in an era when simplicity and reliability reigned supreme. Its **timeless design** ensures compatibility with a wide range of aftermarket parts, from modern suspension systems to performance exhausts, allowing enthusiasts to tailor the bike to their exact specifications. For those who appreciate the raw, unfiltered thrill of motocross, the YZ125 s frame and chassis remain a symbol of adventure, precision, and the enduring spirit of off-road riding.

### **Pros and Cons of Buying a 1993 Yamaha YZ125 (Frame/Chassis: 4EX-21101-00-UJ)**

#### **Pros:**

1. **Classic Reliability** Yamaha s YZ125 has a long-standing reputation for durability and straightforward mechanics. The 125cc single-cylinder engine is known for being easy to maintain and repair, making it a popular choice among beginner and intermediate riders.

2. **Affordable Purchase Price** Older YZ125s, especially those without major frame damage, are often sold at low prices compared to modern dirt bikes. This makes them an attractive option for riders on a budget.

3. **Simple Design** The engine and drivetrain are relatively uncomplicated, which means fewer parts to go wrong. This also makes it easier for DIY mechanics to work on the bike.

4. **Lightweight** The YZ125 is one of the lightest bikes in its class, making it highly maneuverable and ideal for beginners or riders who prefer agility over power.

5. **Aftermarket Support** Due to its popularity, there is a wide range of aftermarket parts, upgrades, and accessories available, including performance chips, suspension upgrades, and custom paint jobs.

6. **Good for Learning** The bike s lightweight nature and manageable power make it suitable for new riders learning to handle a dirt bike.

7. **Fuel Efficiency** The small engine consumes very little fuel, making it cost-effective for casual riding or training sessions.

8. **Resale Value** Well-maintained YZ125s hold their value reasonably well, especially if they have a clean title and no major frame issues.

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#### **Cons:**

1. **Outdated Technology** The bike lacks modern features such as electronic fuel injection (EFI), traction control, or advanced suspension systems found in newer models. This can limit performance and comfort compared to contemporary bikes.

2. **Poor Fuel Economy in Modern Terms** While the engine is fuel-efficient, it does not meet today s emissions standards, and running it on modern fuel (especially ethanol-blended gas) can lead to engine issues over time.

3. **Wear and Tear** A 1993 model will have significant mileage, and parts like the clutch, chain, sprocket, and suspension may require frequent replacement. Rust and corrosion could also be issues if the bike was stored improperly.

4. **Limited Power** The YZ125 s single-cylinder engine produces only about 11-12 horsepower, which is adequate for beginners but insufficient for serious off-road riding or competitive motocross.

5. **No Modern Safety Features** Lack of ABS, advanced braking systems, or ergonomic design elements means less safety compared to today s standards.

6. **Frame Condition is Critical** The frame (4EX-21101-00-UJ) may have hidden damage from crashes or rust. A thorough inspection by a mechanic is essential to avoid buying a bike with structural issues.

7. **Parts Availability** While parts are still available, some may be harder to find compared to newer models, and prices for aftermarket or OEM replacements can add up.

8. **No Warranty** Purchasing a used bike means no manufacturer warranty, so all repairs and maintenance are the buyer s responsibility.

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### **Ending Conclusion:**

The **1993 Yamaha YZ125** is a solid choice if you are looking for a **budget-friendly, lightweight, and mechanically simple** dirt bike particularly for learning, casual riding, or as a project bike. Its reliability and aftermarket support make it appealing to riders who prioritize ease of maintenance over modern performance.

However, if you plan to **ride aggressively, compete, or use the bike frequently**, its lack of power, outdated technology, and potential wear issues may make it less suitable. The **frame condition is the most critical factor** ensure it is free of cracks, rust, or previous damage before purchasing.

### **Recommendation:**

- **Buy it if:** You need a **cheap, easy-to-repair bike** for practice, training, or light off-roading, and you are willing to invest time in maintenance.

- **Avoid it if:** You expect **modern performance, safety features, or plan to ride it heavily** without significant modifications.

- **Before purchasing:** Have a **mechanic inspect the frame, engine, and suspension** for hidden damage. Consider testing the bike on a track if possible.

- **Consider alternatives:** If you want a more capable bike, look at **used YZ125s from the 2000s (which still use the same frame but with minor updates) or newer 125cc bikes** like the **Honda CRF125F or Kawasaki KLX125** for better reliability and features.

Ultimately, the YZ125 can be a great bike for the right rider just manage expectations regarding performance and long-term durability.

Details:

Straight frame rails look good. Has been repainted grey.

part #: 4ex2110100 price

  • $100.00

specifications mocycfra:

  • for models: Yz125, Yz, 125
  • for makes: Yamaha
  • for years: 1993
  • mpn: 4ex-21101-00-uj
  • part type: Frame
  • country of origin: Japan

payments mocycfra:

  • wallet: Paypal
  • credit card: Mastercard
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offer mocycfra:

  • options: Seller-arranged-local-pickup
  • started: May 31, 2026
  • sold: 0
  • quantity: 1
  • availability: In Stock

shipping mocycfra:

seller mocycfra:

  • city: Sandown, New Hampshire
  • rating: 100.0%
  • # reviews: 2107

general mocycfra:

  • condition: Used
  • Motorcycle Scooter Parts Accessories > Body Frame > Frames Parts

returns mocycfra:

  • policy: No Returns
for models: yz125, yz, 125, for makes: yamaha, for years: 1993, part type: frame, country of origin: japan,
category: motorcycle parts > motorcycle scooter parts accessories > body frame > frames parts, sku: 18355115164422773,
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1 offer $100.00 USD
  • Used. Offer #1 priced at $100.00 + $Calculated shipping estimate = $100.00* total. Straight frame rails look good.+$Calculated shipping

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