XL21 VLX – Carbon-Nylon Velocity Stack with Integrated Crankcase Breather for Harley Sportster
Introducing the XL21 VLX, a groundbreaking velocity stack engineered for modern Sportsters. Unlike typical machined parts, this is the industry’s first 3D-extruded one-piece breather stack, crafted from a carbon-fiber reinforced nylon polymer. This advanced process delivers seamless internal crankcase breather chambers, structural integrity, heat resistance, and airflow performance that surpasses OEM plastic components.
At just 4 ounces, the XL21 VLX is incredibly lightweight and mounts cleanly with its included spacer, gasket, mesh filter, bolts, and washers. Its streamlined design exposes more of your Evolution V‑Twin while delivering optimized airflow and internal breathing—without visible hoses or bulk.
Specifications:
Component Type: Velocity stack with integrated crankcase breather system
Material: Carbon-fiber reinforced nylon polymer — extrusion-manufactured
Weight: Approx. 4 oz
Finish: Matte black (concrete grey option available)
Stack Dimensions: 4.5″ opening × 2.5″ height × 6.0″ base
Included Accessories: Spacer, gasket, mesh filter, bolts, washers
Breather System: Internal airflow channels—no external hoses
Made in: USA
Introducing the XL21 VLX, a groundbreaking velocity stack engineered for modern Sportsters. Unlike typical machined parts, this is the industry’s first 3D-extruded one-piece breather stack, crafted from a carbon-fiber reinforced nylon polymer. This advanced process delivers seamless internal crankcase breather chambers, structural integrity, heat resistance, and airflow performance that surpasses OEM plastic components.
At just 4 ounces, the XL21 VLX is incredibly lightweight and mounts cleanly with its included spacer, gasket, mesh filter, bolts, and washers. Its streamlined design exposes more of your Evolution V‑Twin while delivering optimized airflow and internal breathing—without visible hoses or bulk.
Specifications:
Component Type: Velocity stack with integrated crankcase breather system
Material: Carbon-fiber reinforced nylon polymer — extrusion-manufactured
Weight: Approx. 4 oz
Finish: Matte black (concrete grey option available)
Stack Dimensions: 4.5″ opening × 2.5″ height × 6.0″ base
Included Accessories: Spacer, gasket, mesh filter, bolts, washers
Breather System: Internal airflow channels—no external hoses
Made in: USA
Introducing the XL21 VLX, a groundbreaking velocity stack engineered for modern Sportsters. Unlike typical machined parts, this is the industry’s first 3D-extruded one-piece breather stack, crafted from a carbon-fiber reinforced nylon polymer. This advanced process delivers seamless internal crankcase breather chambers, structural integrity, heat resistance, and airflow performance that surpasses OEM plastic components.
At just 4 ounces, the XL21 VLX is incredibly lightweight and mounts cleanly with its included spacer, gasket, mesh filter, bolts, and washers. Its streamlined design exposes more of your Evolution V‑Twin while delivering optimized airflow and internal breathing—without visible hoses or bulk.
Specifications:
Component Type: Velocity stack with integrated crankcase breather system
Material: Carbon-fiber reinforced nylon polymer — extrusion-manufactured
Weight: Approx. 4 oz
Finish: Matte black (concrete grey option available)
Stack Dimensions: 4.5″ opening × 2.5″ height × 6.0″ base
Included Accessories: Spacer, gasket, mesh filter, bolts, washers
Breather System: Internal airflow channels—no external hoses
Made in: USA
Fitment:
Designed to bolt directly onto all Harley-Davidson Sportster models from 2004–2020+, including EFI and CV-carbureted versions.
Works seamlessly with factory and aftermarket intake setups—no custom fitting or hoses needed.
Why Choose the XL21 VLX?
Revolutionary one-piece extrusion: No seams—optimized strength and flow
Ultra-lightweight (just 4 oz): Reduces weight and enhances engine visibility
Internal breather design: Clean look with no external hoses
Superior materials: High-temp, heat-dissipating carbon-nylon composite
Includes full hardware kit: Spacer, gasket, mesh filter, bolts, and washers
Performance engineered: Exceeds OEM for airflow and thermal durability
FAQs:
Q: Is the XL21 VLX a full intake or just a velocity stack?
A: It’s a velocity stack with integrated crankcase breather—not a full intake manifold, but a key performance upgrade.
Q: Will it fit my 2010 EFI Sportster?
A: Yes. It fits all 2004–2020+ Sportster models, both EFI and CV-carb variants.
Q: Do I need to run breather hoses?
A: No—this stack uses an internal breather chamber, so no hoses or catch cans are required.
Q: How is this different from machined parts?
A: It's extrusion-built, allowing complex internal shapes and seamless design—not possible with milling.
Q: Will it improve airflow?
A: Yes. Its optimized shape and material deliver airflow equal to or better than stock, with improved thermal performance.