Harddrive 40MM CV Carb Slide Diaphragm - V-Twin
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.
The Harddrive 40mm CV Carb Slide Diaphragm is an OEM-equivalent replacement component critical for proper fuel delivery in constant-velocity carburetors. This diaphragm regulates the vacuum-operated needle position, ensuring your V-twin maintains consistent fuel mixture across all throttle ranges.
Why riders pick this
- OEM-equivalent replacement for 40mm CV carbs
- Direct-fit diaphragm assembly
- Regulates vacuum-operated needle position
- Ensures proper fuel delivery
- Restores smooth throttle response
A healthy slide diaphragm is essential for the smooth operation of your V-twin's 40mm CV carburetor. If your bike is experiencing rough idle, hesitation, or inconsistent power delivery, a worn or ruptured diaphragm could be the culprit. This Harddrive replacement ensures that your carburetor's slide operates correctly, maintaining optimal fuel flow and throttle response for your Harley or Indian.
Restore Peak Carburetor Function
- OEM-equivalent replacement for 40mm CV carburetors
- Direct-fit diaphragm assembly for easy installation
- Regulates vacuum-operated needle position
- Ensures proper fuel delivery across all throttle ranges
- Critical component for consistent engine performance
Maintain Your V-Twin's Performance
Don't underestimate the impact of a small component like the carb slide diaphragm. A properly functioning diaphragm is key to your V-twin accelerating smoothly and running efficiently. This Harddrive part offers a reliable solution to common carburetor issues, helping you restore that crisp throttle response and dependable performance you expect from your motorcycle.
Specifications
- Brand: Harddrive
- Manufacturer Part #: 40039
- UPC: 191361512254
- Dimensions: 3 in x 3 in x 3 in
- Weight: 0.5 lbs
- Country of Origin: China (Mainland)
Common questions
What is the function of a CV carb slide diaphragm?
The diaphragm responds to engine vacuum, which in turn adjusts the needle position. This action is crucial for maintaining the correct fuel mixture across all throttle positions and RPM ranges.
How can I tell if my carb slide diaphragm needs to be replaced?
Common signs of a failing diaphragm include a rough idle, hesitation or bogging on acceleration, or fuel leaking from the carburetor overflow tubes. A ruptured or stiff diaphragm can cause these issues.
Will this diaphragm fit my Harley-Davidson or Indian Motorcycle?
If your V-twin motorcycle is equipped with a 40mm constant-velocity (CV) carburetor, this diaphragm should fit. It's always best to confirm your specific carb size and model before ordering.
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 | 820-27502 |
| WEIGHT | 0.5 lb |
