Non-Vented Filler Cap & Bung Kit – 1.25"-12 Thread, Compact Design

The non-vented filler cap and bung kit is a compact and clean solution for gas tanks, oil tanks, and fluid reservoirs where external venting is preferred or required. Using our proven 1.25"-12 thread system, this setup delivers a secure, leak-free seal without internal venting.

The cap is CNC machined from lightweight 6061 aluminum with a low-profile 1.5" outer diameter for a sleek and minimal look that fits seamlessly into custom or OEM-style builds. The weld-in bung is available in mild steel, 6061-T6 aluminum, or 304 stainless steel, allowing you to match the material to your project.

While compact, the filler hole is large enough to accommodate most gas pump nozzles and oil fill systems. The included fuel-resistant O-ring provides a tight, durable seal to help prevent leaks.

Product Features:

Thread Size: 1.25"-12 – industry-standard fit

Cap Material: 6061 aluminum, 1.5" outer diameter

Bung Flange O.D.: 1.75", stepped down to 1.5" for easier welding

Seal: Replaceable fuel-resistant O-ring

Bung Material Options: Mild Steel, 6061-T6 Aluminum, or 304 Stainless Steel

Applications: Gas tanks, oil tanks, or any fluid reservoir requiring non-vented sealing

Made in the USA

Sold as a complete kit (1 filler bung + 1 non-vented cap)

Why Choose a Non-Vented Cap?

A non-vented filler cap is ideal for systems that use a separate vent line or where controlled venting is needed. This setup provides a cleaner seal and prevents unwanted seepage through the cap.

Built for custom motorcycle tanks, hot rods, and industrial applications, this non-vented kit combines durability, performance, and a clean, professional look.