XL21 VLX Velocity Stack

XL21 VLX Velocity Stack

$135.00
The XL21 VLX is a cutting-edge carbon-nylon velocity stack engineered to improve both airflow and crankcase ventilation in your Harley-Davidson Sportster intake system. Built with 3D-extruded technology and a seamless integrated crankcase breather, this lightweight (4 oz) performance component provides superior heat resistance and airflow performance. The XL21 VLX mounts easily with a full hardware kit, offering a clean, hose-free installation that exposes more of your Evolution V-Twin motor.
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Product Information

XL21 VLX is the first one-piece 3D-extruded velocity stack with a fully integrated internal crankcase breather.

Manufactured from carbon-fiber reinforced nylon polymer, this stack delivers optimized airflow, superior thermal resistance, and structural strength beyond traditional OEM plastic stacks.

Weighing just 4 oz, the XL21 VLX reduces intake mass while exposing more of the Evolution V-Twin engine. Internal breathing channels eliminate external hoses, creating a clean, performance-focused installation.

Compatible with both EFI and CV-carbureted Sportsters, it installs easily using the included hardware kit and works with factory or aftermarket intake systems.

Specifications
Component Type
Velocity stack with integrated breather
Material
Carbon-fiber reinforced nylon polymer
Manufacturing
3D-extruded one-piece design
Weight
Approx. 4 oz
Finish
Matte black (grey optional)
Dimensions
4.5″ opening × 2.5″ height × 6.0″ base
Breather System
Internal airflow channels
Included
Spacer, gasket, mesh filter, bolts, washers
Origin
Made in the USA
Features
  • One-piece 3D-extruded seamless construction
  • Ultra-light 4 oz design improves engine visibility
  • Integrated crankcase breather — no external hoses
  • High-temp carbon-nylon composite resists heat soak
  • Optimized airflow compared to OEM stacks
  • Includes complete installation hardware kit
  • Clean, exposed V-Twin aesthetic
Fitment
Harley-Davidson Sportster (2004–2020+)
EFI & CV-carbureted engines
Factory and aftermarket intake systems
No external breather hoses required
Direct bolt-on installation
Why Choose
Seamless extrusion enables complex internal airflow channels
Improved thermal performance over OEM plastic stacks
Ultra-lightweight performance component
Integrated breather keeps engine bay clean
Engineered for both performance and visual impact
FAQs
Is this a full intake system?

No. It is a velocity stack with integrated breather, not a full intake manifold.

Will it fit a 2010 EFI Sportster?

Yes. Compatible with all 2004–2020+ Sportsters.

Do I need breather hoses?

No. Internal airflow channels handle crankcase ventilation.

How is extrusion different from machining?

Extrusion allows seamless complex internal airflow paths impossible with machining.

Will airflow improve?

Yes. Designed for optimized airflow and improved thermal performance.

Designed & Built in the USA

Every Kinetic product is designed and manufactured in the United States. Keeping our work in-house allows us to control quality, refine fitment, and stand behind every part we make.

A Decade of Hands-On Experience

Founded in 2013. A decade of machining, installing, riding and refining components on real bikes — not just in a lab. That experience shows in the quality of every part we ship.

Designed by Riders & Builders

Every product is shaped by hands-on building and riding experience, with practical decisions made where it matters most.

Innovation Meets Passion

Made in the USA

Founded in 2013 by Mike Le, Kinetic Motorcycles was built on a simple belief: motorcycle parts aren't generic hardware — they're personal. Every product begins as an original idea, designed by Mike and developed entirely in-house.

We don't rely on templates or outsourced shortcuts. Each part is shipped by hands-on fabrication experience and time spent riding, testing, and refining. Whether you're dialing in a daily rider or building something truly your own, our focus is the same — create parts that feel intentional, functional, and worthy of your motorcycle.

Innovation Meets Passion

What Our Customers Say

Really happy with the product. Took a while to get my order but they were out of the spark plug cables I ordered. I had to email and inquire what the deal was. They were super helpful once I initiated communication. Would have been cool to get some swag or something since they took so long. But the relocator is great. I really love it. And they responded promptly once I reached out to them. Their customer service is truly fantastic.

Brian Hopkins
Ignition Coils Relocator (L.E.) Relocator for Harley-Davidson Sportster

I had some questions on some bars, so I DMd them on Instagram. The dude I talked to was super helpful. I purchased the shirt because of his response. I’ll rep the brand due to the customer service.

Chet Michaelsen
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Precision-machined and bolt-on perfect. Took 30 minutes to install and the difference is night and day.

Samuel P.
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Customer support answered my DMs within an hour. Shipping was on point, packaging was premium.

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