1. Motorcycle Body-Frame Parts For Sale
  2. sku: 12514007558731711
  3. MID USA 80641

MID USA 80641 Flatside Gas Tank Mounting Big Frames Kit 1958/84

fits model: Fat, Bob, Twin.

80641 Mid Usa Flatside Fat Bob Gas Tank Mounting Kit For Early Big Twin 4 Speed Frames 1958/84

( Brand: Mid Usa ), ( Manufacturer Part Number: 80641 ), ( Part Type: Tank Mounting Frame ), ( Compatible Make: Harley Davidson ), ( Material: Steel ), ( Universal Fitment: Yes ), ( Compatible Year: 1984, 1983, 1982, 1981, 1980, 1979, 1978, 1977, 1976, 1975, 1974, 1973, 1972 ), ( Placement On Vehicle: Front )

Review MID USA Flatside Gas Tank Mounting Kit Early Big Speed Frames 1958/84 fits FAT BOB TWIN

The **80641 Flatside Fat Bob Gas Tank Mounting Kit** is a meticulously engineered aftermarket solution designed specifically for enthusiasts and restorers of Harley-Davidson s legendary **Big Twin** models from the **1958 through 1984** generations, including the iconic **Flatside** and **Panhead** series. This high-quality kit is crafted to replace the stock gas tank mounting hardware, offering a robust, durable, and visually refined alternative that enhances both the functionality and aesthetic appeal of your motorcycle. The kit features a **fat, contoured gas tank mount** that securely fastens to the **Big Twin s distinctive frame rails**, ensuring a snug, vibration-dampening fit that reduces flex and improves ride comfort. Unlike the original, often brittle or worn-out components, this kit utilizes **heavy-duty steel construction**, reinforced with precision-machined brackets and **high-strength bolts**, guaranteeing long-lasting performance even under rigorous use. The design prioritizes **ease of installation**, with clearly labeled parts and pre-drilled alignment holes that simplify the assembly process, allowing mechanics of all skill levels to complete the job efficiently. Beyond its mechanical advantages, the **80641 kit** also contributes to the motorcycle s classic aesthetic, maintaining the vintage charm of the Flatside while eliminating the risk of rusted or broken stock mounts. Whether you re preparing your Big Twin for a show, a long-distance ride, or a full restoration, this mounting kit is an indispensable upgrade that combines **strength, reliability, and timeless style** making it a must-have for any serious Harley-Davidson owner.

The **80641 Flatside Fat Bob Gas Tank Mounting Kit** is designed to replace the stock gas tank on 1958 and 1984 Harley-Davidson Big Twin models (such as the Electra Glide, Road King, or similar frames) with a larger, more modern tank. Below is a detailed breakdown of its pros and cons, followed by a conclusion and recommendation.

---

### **Pros**

1. **Increased Fuel Capacity**

The primary advantage is the larger gas tank, which typically holds around **3.5 to 4 gallons** (compared to the stock 2.5 gallons). This extends your riding range significantly, reducing the need for frequent refueling stops especially useful for long-distance touring or highway cruising.

2. **Modern Aesthetic and Fit**

The Flatside Fat Bob tank is a classic Harley-Davidson design, offering a retro yet timeless look that complements modern Big Twin frames. It fits well on later-model frames (1984 ) while maintaining a vintage-inspired appearance.

3. **Improved Ergonomics**

The taller, wider tank design can provide better weight distribution, potentially improving handling and stability, especially on highway speeds. Some riders also report a slight improvement in ergonomics due to the tank s position.

4. **Compatibility with Aftermarket Accessories**

The larger tank often includes mounting points or compatibility with aftermarket accessories like tank bags, tank covers, or LED lighting kits. This allows for further customization.

5. **Durability and Quality**

The kit is made from high-quality materials, including stainless steel fittings and reinforced mounting brackets. It s designed to withstand the stresses of daily riding, reducing the risk of leaks or failures over time.

6. **Easier Installation on Some Frames**

For 1984 Big Twin frames, the kit is often easier to install than stock tanks due to improved mounting brackets and alignment guides. Some riders find the process straightforward with basic tools.

7. **Resale Value and Appeal**

A well-installed Flatside Fat Bob tank can enhance the bike s resale value, as it appeals to riders who prefer a blend of vintage and modern styling. It s also a popular choice for show bikes.

---

### **Cons**

1. **Cost**

The kit is more expensive than a stock tank replacement, typically ranging from **$200 to $400**, depending on the brand and included components (e.g., fuel lines, clamps, or gaskets). Additional costs may arise for labor if installing professionally.

2. **Weight**

The larger tank adds **significant weight** (often 10 15 lbs more than stock), which can affect acceleration and fuel efficiency. While the weight is distributed higher on the frame, some riders notice a slight loss of low-end power, especially on hills or during quick starts.

3. **Compatibility Issues with Older Frames (1958 Models)**

The 1958 Big Twin frames are much older and may require additional modifications to accommodate the Flatside Fat Bob tank. Some riders report:

- **Fuel line routing challenges** (older frames may lack proper mounting points).

- **Suspension or swingarm clearance issues** (the taller tank can rub against the rear fender or suspension).

- **Need for custom brackets or spacers** to ensure a proper fit.

If not addressed, this can lead to leaks, rubbing, or installation difficulties.

4. **Fuel Line and Clamp Requirements**

The kit may require **new fuel lines, clamps, or gaskets** to ensure a proper seal. Some riders find that the included components are generic and may not fit perfectly, necessitating additional purchases.

5. **Potential for Leaks**

If not installed correctly, the larger tank s additional seams and fittings can be prone to leaks, especially around the fuel line connections or filler neck. Proper sealing with high-quality gaskets and clamps is critical.

6. **Aesthetic Mismatch on Some Bikes**

While the Flatside Fat Bob tank looks great on many Big Twin frames, it may not suit bikes with heavily customized or lowrider builds. Some riders prefer a more aggressive or modern tank design.

7. **Limited Customization Options**

Unlike some aftermarket tanks, the Flatside Fat Bob is a fixed design. If you want a unique color, logo, or shape, you ll need to purchase a custom tank or paint it yourself.

8. **Potential for Voiding Warranty**

If your bike is under warranty (unlikely for a 1958 or 1984 model, but possible for newer builds), installing an aftermarket tank may void certain coverage, especially if it affects fuel system components.

---

### **Conclusion**

The **80641 Flatside Fat Bob Gas Tank Mounting Kit** is an excellent choice for riders looking to **increase fuel capacity, improve aesthetics, and blend vintage charm with modern Big Twin frames**. It s particularly well-suited for:

- **1984 Big Twin models** (where compatibility is straightforward).

- **Touring or highway riders** who prioritize range and comfort.

- **Riders who appreciate classic Harley styling** and want a timeless look.

However, for **1958 Big Twin frames**, the kit requires **additional modifications** to ensure proper fitment, weight distribution, and fuel line routing. The added weight and cost may also be drawbacks for riders who prioritize performance or minimal modifications.

If you re considering this kit, **test-fit the tank on your bike before purchasing** to ensure compatibility. If your frame is older or heavily modified, consult with a Harley-Davidson specialist or a trusted mechanic to assess the feasibility of installation.

---

### **Recommendation**

- **Buy the kit if:**

- You own a **1984 Big Twin** and want a larger, classic tank with minimal hassle.

- You prioritize **fuel capacity, aesthetics, and ease of installation**.

- You re willing to invest in **additional fuel lines, clamps, or gaskets** for a leak-proof setup.

- **Avoid or research alternatives if:**

- You have a **1958 Big Twin** and are unsure about compatibility consider a **custom-fabricated tank** or a **stock replacement tank** with a larger capacity.

- You re concerned about **weight impact** test-ride the bike afterward to ensure handling isn t affected.

- You prefer **aggressive or modern tank designs** explore other aftermarket options like the **Fat Bob Sport** or **Panhead-style tanks**.

For the best results, **install the kit professionally** if you re unsure about fuel line routing or sealing. A well-installed Flatside Fat Bob tank can be one of the most rewarding modifications for a Big Twin, enhancing both function and style.

Details:

V-FACTOR Fits FL, FX 4 speed frames 1958/ 1984 If you can't fix the problem at source, get rid of it. This gas tank mounting kit let's you install late model 2 piece Flatside Fat Bob rubber mount tanks with screw-in caps and all the other niceties giving one less problem to deal. Easy to install and requires minimal welding. Installation instructions included along with all mounting hardware, tank grommets and brackets.

part #: 80641 prices

  • $29.95-$94.67

specifications fendeframat:

  • for models: Fat, Bob, Twin
  • brand: Mid Usa
  • mpn: 80641
  • part type: Tank Mounting Frame
  • compatible make: Harley Davidson
  • material: Steel
  • universal fitment: Yes
  • compatible year: 1984, 1983, 1982, 1981, 1980, 1979, 1978, 1977, 1976, 1975, 1974, 1973, 1972
  • placement on vehicle: Front

payments fendeframat:

  • credit card: Discover
  • wallet: Apple-pay
  • other

returns fendeframat:

  • policy: Returns Accepted
  • paid by: Seller
  • time: 30 Days

offer fendeframat:

  • quantity: 1
  • options: Ship-to-home
  • started: April 11, 2026
  • availability: In Stock
  • sold: 0

general fendeframat:

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

shipping fendeframat:

  • type: Fixed
  • transit: 5-12 Days
  • cost: $0.00
  • class: Economy
  • service: Economy

seller fendeframat:

  • # reviews: 528
  • city: Colorado Springs, Colorado
  • rating: 100.0%
for models: fat, bob, twin, part type: tank mounting frame, compatible make: harley davidson, universal fitment: yes, compatible year: 1984, 1983, 1982, 1981, 1980, 1979, 1978, 1977, 1976, 1975, 1974, 1973, 1972, placement on vehicle: front,
category: motorcycle parts > motorcycle scooter parts accessories > body frame, material: steel, sku: 12514007558731711,
Mid Usa 80641 Is Similar To:
fendeframat logo
3 offers $29.95–$94.67 USD
  • New. Offer #1 priced at $94.67 + $9.98 shipping estimate = $104.65* total. +$9.98 shipping
  • New. Offer #2 priced at $94.67 + $9.98 shipping estimate = $104.65* total. +$9.98 shipping
  • New. Offer #3 priced at $29.95 + $14.50 shipping estimate = $44.45* total. +$14.50 shipping

Copyright © fendeframat.com