Smooth KustomTech solder cap: the purity of minimalist design
Less is more. If you subscribe to this philosophy, this Smooth-style weld-on cap from KustomTech is for you. With its perfectly smooth and rounded profile, free of fins or embellishments, it embodies the very essence of minimalist design applied to custom motorcycles. A clean, uncluttered piece that lets the quality of the materials and machining speak for itself.
Billet aluminium with a clean profile
Machined from a solid block of billet aluminum, this Smooth gas cap boasts a perfectly smooth and consistent profile. The mirror-polished finish highlights the gentle curves and flawless surface of this piece. It's the ideal gas cap for clean, contemporary custom projects, whether it's a minimalist bobber, a tracker, or a sleek café racer.
Universal welding system
Like its Acorn-style cousin, this Smooth cap comes with a raw steel tube ready to be welded onto any steel tank. Whether you're building a custom tank or customizing an existing one, this system offers complete flexibility. The tube welds cleanly, and the cap screws onto it with millimeter precision.
Versatility: Petrol and oil
This cap is suitable for both gasoline and oil tanks. Its universal design makes it a versatile choice for builders who want to coordinate all the caps in their project with the same Smooth style. Imagine a tank with two identical Smooth caps: it's perfect symmetry, the detail that elevates a project to the realm of polished builds.
Technical characteristics
Material: CNC machined billet aluminum. Finish: Mirror polished. Profile: Smooth. Weld-on tube: Raw steel included. Compatible with: All steel tanks. Part number: 10-012. Made in Italy by KustomTech.
See as well
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Technical specifications — Smooth KustomTech style weld-on cap in polished billet aluminum for gasoline and oil tanks
- Brand: KustomTech (Italy)
- Material: Aluminium
- finish: Poli
- Manufacturing: CNC machining from solid stock (Italian workshop)
- Official distributor in France: Holdfast Marseille
- Shipping time: 48 hours from Marseille
Compatibility of Harley Davidson fuel and oil caps
Compatible with all Harley Davidson models: Sportster 883/1200 (1991+), Dyna, Softail, Touring (Road King, Street Glide). For Touring models with a lock or Tour Pak, please check the exact model on the product page.
Installation
Direct plug: unscrew the old cap, screw in the KustomTech. For weld-on caps, a mini welder on the tank is required (typically 30-45 minutes at a specialist).
FAQ — Fuel and oil caps
Is it waterproof?
Yes. High-density nitrile rubber O-ring + precision machined threads = not a leak. E10 fuel and 4-stroke engine oil resistance tested.
Is the thread compatible?
Standard Harley Davidson thread (left-hand thread for the fuel cap on most models). Check the exact model on the product page before ordering.
Difference between screw-on and weld-on?
The screw-on cap = 30-second installation, plug-and-play. The weld-on cap = total customization, requires welding on a custom tank (chopper bobber).
Why buy from Holdfast Marseille?
- Official distributor of KustomTech France since 2019
- Permanent stock in Marseille, 48-hour shipping within mainland France
- Free delivery on orders over €150
- Responsive customer service from Marseille (no returns from Italy)
- KustomTech 2-year warranty
- Expert biker advice: call +33 6 45 57 84 26
Julien A. –
Ultra-sleek design, exactly what I was looking for for my tracker project. The smooth profile gives it a clean and modern look. The aluminum is well polished and the tube welds easily onto standard steel.
Maxime H. –
Minimalist but effective cap. KustomTech quality is always top-notch. I used it on a tank I made myself, and the result is clean. However, it's a bit pricey for a weld-on cap.