Harddrive OEM #3577 Breather Bolt - Harley Big Twin & Sportster
About Harddrive
Harddrive is the house performance and replacement line built for American V-twins, covering everything from engine hardware and electrical to controls, lighting and chassis parts. The range is aimed squarely at Harley-Davidson and Indian riders who want a direct-fit part without dealer pricing, and it spans decades of model years — from Evolution-era Softails to current Milwaukee-Eight baggers.
This Harddrive breather bolt is a direct OEM replacement for part #3577, crucial for maintaining proper engine breathing on your Harley-Davidson. It mounts to the breather backing plate on the crankcase, ensuring a sealed system that prevents oil leaks and directs vapors for efficient operation. Essential for both Big Twin and select Sportster models.
Why riders pick this
- OEM #3577 direct replacement
- Seals crankcase breather system
- Prevents oil leaks and promotes clean engine operation
- Fits Big Twin models 1993-1999
- Fits select Sportster models 1995-2000
Proper crankcase ventilation is vital for the longevity and performance of your Harley-Davidson engine. This Harddrive breather bolt serves as a direct, high-quality replacement for the OEM part #3577. It plays a key role in sealing the breather system, preventing oil from escaping and ensuring that engine vapors are correctly routed into the intake. This helps maintain a clean engine and efficient combustion.
Reliable Engine Breathing
- Direct replacement for Harley-Davidson OEM part #3577
- Seals the breather backing plate for optimal engine function
- Helps prevent oil leakage from the crankcase
- Routes engine vapors into the intake system
Maintain Your V-Twin
Over time, breather bolts can wear or become damaged, leading to potential issues with your engine's breathing system. Replacing a worn breather bolt with this Harddrive unit ensures your Big Twin or Sportster continues to operate as it should. It's a small but critical component for keeping your V-twin running strong and clean, fitting various models from the mid-90s. Always confirm fitment against your specific year and model's parts manual.
Specifications
- Brand: Harddrive
- Manufacturer Part #: 19-131
- UPC: 191361165627
- Length: 6.1 in
- Width: 3.74 in
- Height: 0.78 in
- Weight: 0.1168 lbs
- Country of Origin: China (Taiwan)
Common questions
What models does this breather bolt fit?
This breather bolt fits Harley-Davidson Big Twin models from 1993-1999 and select Sportster models from 1995-2000. It's crucial to verify your specific year and model against the OEM parts manual to confirm exact fitment.
What is the function of a breather bolt?
A breather bolt is part of the engine's crankcase ventilation system. It seals the breather backing plate, helping to prevent oil leakage and directing engine vapors into the intake system for re-combustion, which is important for engine health and emissions control.
Do I need any special tools for installation?
Installation of a breather bolt typically requires standard hand tools. Consult your Harley-Davidson service manual for specific instructions and torque specifications for your model.
Ordering from Vtwinbikers
- Brand new, sourced through authorized US distribution — never used, never grey-market.
- Not sure it fits? Use Shop by Bike to filter by your year and model, or email us and we will confirm before you order.
- Harley-Davidson and Indian Motorcycle is all we do, so you are talking to people who ride what you ride.
| BRAND | Harddrive |
| TYPE | Intake/Carb/Fuel System |
| SKU | 820-50540 |
| WEIGHT | 0.12 lb |
