1. Motorcycle Frames Offers
  2. sku: 17529608054482722
  3. TWIN 51-0509

V-TWIN MANUFACTURING 51-0509 Nos Top Motor Mount Set El

fits model: Fl, Knucklehead. year: 1936–1947.

51-0509 V-twin Manufacturing Nos Knucklehead Top Motor Mount Set 1936 - 1947 El Fl U Ul

( Brand: V-twin Manufacturing ), ( Manufacturer Part Number: 51-0509 ), ( Frame Type: Rigid ), ( Type: Mount ), ( Machine Type: Dual Sport Motorcycle, Off-road Motorcycle, Street Motorcycle ), ( Material: Steel ), ( Vintage Part: Yes ), ( Country Of Origin: United States ), ( Placement On Vehicle: Upper )

Review V TWIN MANUFACTURING Nos Top Motor Mount Set El Ul fits KNUCKLEHEAD FL 1936–1947

The **V-Twin 51-0509 NOS Knucklehead Top Motor Mount Set** is a meticulously preserved, no-sale (NOS) aftermarket component designed exclusively for Harley-Davidson s legendary **1936 1947 EL and FL Knucklehead** models, offering both authenticity and enhanced functionality for vintage enthusiasts and restorers. Crafted from high-quality, heat-treated steel, this top motor mount set is a direct replacement for the original castings, ensuring a perfect fit while maintaining the iconic aesthetic of the era. The set includes all necessary components such as the upper engine mounts, gudgeon pins, and mounting hardware to securely fasten the cylinder assembly to the crankcase, a critical junction that balances power delivery and structural integrity. Unlike modern aftermarket alternatives, this NOS part retains the original machining and finish, complete with the distinctive **Knucklehead s signature knuckle-shaped valve covers**, which not only contribute to the engine s vintage charm but also provide a secure housing for the pushrods and rocker arms. Ideal for restorers seeking to preserve the mechanical and visual integrity of their classic Harley, this mount set is a testament to the craftsmanship of an earlier era, where durability and simplicity reigned supreme. Whether integrated into a fully restored EL or FL or used as part of a meticulous rebuild, this NOS component ensures that the engine s performance remains true to its original intent delivering the deep, throaty growl and responsive power that defined Harley-Davidson s golden age.

### **Pros and Cons of Buying a V-Twin 51-0509 NOS Knucklehead Top Motor Mount Set (1936 1947 EL/FL Harley-Davidson)**

#### **Pros:**

1. **Original, Never-Used Condition (NOS)** The "New Old Stock" designation means this part has never been installed or used, ensuring it is in pristine, factory-fresh condition. This eliminates concerns about wear, corrosion, or prior damage.

2. **Authentic Restoration or Classic Build** If you're restoring a vintage Harley-Davidson (1936 1947 EL/FL model) or building a period-correct bike, NOS parts like this top motor mount set guarantee historical accuracy. Aftermarket replacements may not match the original fit, finish, or styling.

3. **High-Quality Castings** Harley-Davidson s early motor mounts were made from durable cast iron, which, when properly maintained, can last decades. The knucklehead-era parts are known for their robust construction, though they may require some machining or alignment work during installation.

4. **Increased Value for Enthusiasts** For collectors or riders who prioritize authenticity, NOS parts significantly enhance the bike s value. Future buyers or appraisers will recognize the part s originality as a major plus.

5. **Potential for Long-Term Reliability** If installed correctly and maintained, these parts can provide decades of service, especially in a well-preserved or lightly used bike. The knucklehead engine is legendary for its durability when kept in good condition.

6. **Aesthetic Appeal** The knucklehead s distinctive design is a hallmark of early Harley-Davidson engines. Using NOS parts preserves the bike s vintage look, which is desirable for show bikes or classic rides.

7. **Support for Vintage Harley Culture** Purchasing NOS parts from reputable sellers helps sustain the market for authentic vintage components, keeping restoration projects viable for future enthusiasts.

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#### **Cons:**

1. **High Cost** NOS parts are significantly more expensive than aftermarket or used alternatives. The price reflects their rarity, originality, and the labor costs associated with sourcing them. For a budget-conscious builder, this can be a major drawback.

2. **Limited Availability** Finding NOS parts for specific Harley models, especially older ones like the 1936 1947 EL/FL, can be challenging. Sellers may have limited stock, and prices can fluctuate based on demand.

3. **Installation Challenges** Knucklehead-era parts often require precise machining, alignment, or modification to fit modern standards (e.g., updated engine mounts, gaskets, or fasteners). This may necessitate professional labor or specialized tools, adding to the overall cost.

4. **Weight and Ergonomics** The knucklehead engine and its associated components are heavier than later Harley designs. This can affect handling, fuel efficiency, and rider comfort, particularly in modern applications where weight distribution is optimized.

5. **Maintenance Considerations** Older castings may develop hairline cracks over time, especially if the bike is ridden hard or exposed to extreme temperatures. Regular inspections and potential welding or replacement of cracked parts may be required.

6. **Compatibility Issues** While this part set is designed for 1936 1947 EL/FL models, subtle variations in later or earlier models (e.g., 1935 or 1948 ) may require adjustments. Double-checking compatibility with your specific bike is essential.

7. **Ethical and Market Concerns** The NOS market can sometimes involve ethical dilemmas, such as parts being "reconditioned" (e.g., cleaned, polished, or lightly used) and mislabeled as NOS. Buying from a trusted seller with verifiable provenance is critical to avoid scams.

8. **Time-Consuming Restoration** Using NOS parts often means the rest of the bike must also be restored to match, as mixing old and new components can detract from the vintage aesthetic. This can extend the project timeline and budget.

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### **Conclusion:**

Buying a **V-Twin 51-0509 NOS Knucklehead Top Motor Mount Set** is a **highly rewarding but costly** decision best suited for **serious vintage Harley-Davidson enthusiasts, collectors, or restorers** who prioritize authenticity and historical accuracy over cost efficiency. The part s value lies in its **originality, durability, and aesthetic appeal**, making it ideal for show bikes, concours entries, or projects where every detail matters.

However, if your primary goal is **performance, cost savings, or a modernized build**, aftermarket or used alternatives may be more practical. The trade-off between **purity and practicality** ultimately depends on your priorities as a rider or builder.

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### **Recommendation:** - **Buy the NOS set if:**

- You are restoring a **1936 1947 EL/FL Harley-Davidson** and want **100% authenticity**.

- You are a **collector or competitor** who values original parts for resale or show value.

- You have the **budget and patience** to invest in a high-quality, long-term project.

- You are working with a **trusted seller** who can verify the part s NOS status.

- **Consider alternatives if:**

- You are on a **tight budget** and can compromise on authenticity.

- You plan to **modify the bike significantly** (e.g., modernizing the engine or frame), making NOS parts less critical.

- You prefer **aftermarket parts** that may offer better compatibility or warranties.

- You are unsure about the **long-term maintenance** required for older castings.

For most **casual riders or budget-conscious builders**, aftermarket top motor mount sets (e.g., from **Harley-Davidson Performance Parts, Evo, or other reputable brands**) provide a **cost-effective, reliable alternative** without sacrificing too much in terms of performance or fit. However, if you re building a **showstopping vintage Harley**, the NOS option is unmatched in its ability to preserve the bike s heritage.

Details:

1941 1947 Harley-Davidson FL 74. Excellent condition for a builder. PART DETAILS: Manufacturer: V-Twin Manufacturing, Part Number: 51-0509, Type: Top engine mount / seat tee tank mount, Thread Size: 5/16, Construction: Stamped steel 2-piece set. More parts available.

Shipping costs are estimates. I do my best to describe everything accurately, but don't know every single detail for year and model. This set remains factory sealed, making it ideal for collectors or high-end restorations. Rigid frame applications weld-on installation.

Please examine photos for condition and quality. Parts appear cleaner than typical sealed examples with only light surface rust and minimal patina. Whats pictured is whats included. FITS: 1936 1940 Harley-Davidson EL 61.

Please see my other listings. Condition: NOS, opened for inspection due to torn packaging. Please view photos and inspect as well. More coming soon.

I ll gladly combine shipping on multiple orders. New Old Stock V-Twin 51-0509 Knucklehead top motor mount set, correct weld-on restoration component for early Harley rigid frames.

part #: 510509 price

  • $127.50

specifications mocycfra:

  • for models: Fl, Knucklehead
  • for years: 1936-1947
  • brand: V-twin Manufacturing
  • mpn: 51-0509
  • frame type: Rigid
  • type: Mount
  • machine type: Dual Sport Motorcycle, Off-road Motorcycle, Street Motorcycle
  • material: Steel
  • vintage part: Yes
  • country of origin: United States
  • placement on vehicle: Upper

seller mocycfra:

  • rating: 99.7%
  • # reviews: 4117
  • city: Powhatan, Virginia

offer mocycfra:

  • started: April 2, 2026
  • options: Ship-to-home
  • availability: In Stock
  • quantity: 1
  • sold: 0

returns mocycfra:

  • policy: No Returns

payments mocycfra:

  • credit card: Mastercard
  • other
  • wallet: Paypal

general mocycfra:

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

shipping mocycfra:

  • carrier: UPS
  • type: Fixed
  • class: Economy
  • transit: 11-18 Days
  • service: UPS Ground Saver
  • cost: $0.00
for models: fl, knucklehead, for years: 1936-1947, frame type: rigid, type: mount, machine type: dual sport motorcycle, off-road motorcycle, street motorcycle, vintage part: yes, country of origin: united states, placement on vehicle: upper,
category: motorcycle parts > motorcycle scooter parts accessories > body frame > frames parts, material: steel, sku: 17529608054482722,
V-twin Manufacturing 51-0509 Is Similar To:
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1 offer $127.50 USD
  • New. Offer #1 priced at $127.50 + $0.00 shipping estimate = $127.50* total. Type: Top engine mount / seat tee / tank mount. This set remains factory sealed, making it ideal for collectors or high-end restorations.FREE SHIPPING

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