TC Bros steel weld-in petcock bungs are essential components for custom motorcycle fuel tank and oil tank fabrication. These precision-manufactured NPT (National Pipe Thread) bungs provide secure, leak-proof mounting points for petcocks and tank fittings. Available in 1/4" and 3/8" NPT sizes to accommodate different petcock and fitting requirements.
1/4" NPT: The 1/4" NPT size is the most common size for motorcycle fuel tank petcocks and oil tank fittings. This size works with standard petcocks and provides adequate flow for most applications. If you're replacing an existing petcock or using a standard aftermarket petcock, 1/4" NPT is likely the correct size.
3/8" NPT: The 3/8" NPT size offers a larger opening for higher flow applications or when using specific fittings that require the larger thread size. This size is ideal for custom applications, larger displacement engines, or when maximum fuel flow is desired. Always verify your petcock or fitting thread size before ordering.
NPT (National Pipe Thread) threads are tapered, meaning the diameter gradually decreases along the length of the threads. This tapered design is critical for creating a leak-proof seal. As you tighten an NPT fitting into an NPT bung, the tapered threads wedge together, creating a tight, sealed connection.
Important: NPT threads are ONLY designed to be used with corresponding NPT threaded fittings or pipe. Do not attempt to use standard bolts, machine screws, or non-NPT hardware with these bungs, as they will not seal properly and may leak.
Proper installation is critical for leak-free performance:
Safety Warning: Welding on fuel tanks is extremely dangerous if not done properly. Fuel vapors can ignite or explode. Only qualified professionals should weld on fuel tanks. Always follow proper safety procedures including complete fuel drainage, tank purging, and ventilation.
Each pair of TC Bros steel weld-in petcock bungs is precision-manufactured from premium American 1018 cold rolled steel to ensure reliable welding, proper thread engagement, and leak-free performance for your custom motorcycle fuel or oil tank.
TC Bros.-Leather Cushion Washers with 3/8 inch Hole 10 pack
Regular price $13.95These leather washers are perfect for protecting your paint and are more durable than rubber. The cushioning & dampening effect that these washers provide is perfect for installing between your frame and mounting tabs found on gas tanks, fenders, oil tanks, or anything else you want to protect from vibration. Also great for use under solo seat springs to prevent squeaking. Dimensions are 1 inch diameter x 3/8 inch hole x 1/8 inch thick. Sold in pack of 10 washers.
TC Bros Weld-On Rear Fender Mounts (Single Hole, Standard & Ribbed)
Regular price $25.95TC Bros weld-on rear fender mounts provide secure, professional mounting solutions for rear fenders on custom motorcycle builds. These precision-manufactured steel mounts are designed to be welded onto your frame, offering three distinct styles to match your build requirements and aesthetic preferences.
Single Hole: The minimalist single hole design is perfect for builders who want a clean, simple look with minimal hardware visible. Ideal for lightweight fenders and builds where simplicity is key. The single mounting point provides adequate support for most rear fender applications while maintaining a sleek profile.
Standard: The classic dual-hole design offers traditional styling with proven reliability. Two mounting holes provide secure attachment points for your fender struts or mounting hardware. This is the most versatile option, working well with virtually any custom build style from choppers to bobbers to cafe racers.
Ribbed: The ribbed design adds structural reinforcement through integrated ribs, providing maximum strength for heavy-duty applications. The ribbed pattern also adds a distinctive visual element that complements builds with other ribbed or finned components. Perfect for larger fenders, touring customs, or builds where extra strength is desired.
These fender mounts are designed to be welded onto your motorcycle frame at the desired mounting location. Proper positioning and alignment are critical for correct fender fitment and appearance. We recommend:
Professional installation is recommended if you're not experienced with welding and frame fabrication. Each TC Bros fender mount is manufactured to exacting standards for reliable performance on your custom motorcycle build.
TC Bros Threaded Steel Bungs - Standard (5/16-18 & 3/8-16)
Regular price $27.95TC Bros standard threaded steel bungs are essential fabrication components for custom motorcycle builds. These precision-manufactured bungs provide secure, threaded mounting points for gas tanks, seat pans, fenders, battery boxes, and countless other components. Available in two thread sizes and three lengths to accommodate various mounting applications.
Thread Sizes: 5/16-18 or 3/8-16
Lengths: 1/2", 1", or 1.5"
Depending on your specific application, you might need a different style of bung or mounting solution:
Alternative Bung Styles:
Non-Threaded Mounting Solutions:
These bungs are designed to be welded onto your motorcycle frame, gas tank, fenders, or other components at the desired mounting location. Proper positioning and alignment are critical for correct fitment and function. We recommend:
Professional installation is recommended if you're not experienced with welding and frame fabrication. Each TC Bros steel bung is precision-manufactured to exacting standards for reliable performance on your custom motorcycle build.
Prism Supply Co Weld-On License Plate Bracket
Regular price $27.00The good folks over at Prism Supply Co have designed a license plate bracket to work with any new or vintage license plate. It's perfect for that sissy bar application. Comes in either stainless or mild steel with a thickness of 8 gauge or 0.1285".
Don't forget a set of Glass License Plate Jewels for that vintage custom look!
TC Bros King & Queen Seat Mounting Kit
Regular price $77.95Everything you need to mount your TC Bros. King & Queen Seat. Weld-on bracket is coped to fit our Sportster hardtail perfectly. Mounts are slotted if you want to use this for a universal/custom use.