Petcock | Honda CJ360 / CB550 (K3 & K4) / CB550F (1977) / CB750 (1976-1978)

Petcock | Honda CJ360 / CB550 (K3 & K4) / CB550F (1977) / CB750 (1976-1978)

OEM-style riveted replacement petcock for Late Honda models like the CJ360, CB550K, and CB750K that use a non rebuildable petcock.

Why You Need This

The original factory petcocks on Honda CJ360, CB550 K2/K3, late CB550F, and CB750 models were riveted shut and cannot be rebuilt. Over time, the internal rubber components dry out, which means even original used petcocks are likely to leak. Our replacement petcock is configured like the original but with fresh rubber components and a fresh in tank primary filter element for long service life. It also features properly sized internal fuel passages to support the maximum fuel flow required by Honda CB550 and CB750 motorcycles.

Specifications

Note: This petcock has a right-side fuel outlet. While some original Honda petcocks used downward or rear outlets, this right-exit version is the best option we’ve found for tight clearance fitment while maintaining proper fuel flow for motorcycles like the Honda CB750.

Installation

Difficulty: Beginner

Tools needed: 22mm wrench or adjustable wrench

1. Drain the gas tank and screw the original petcock from the tank.
2. A clean, debris, and rust free fuel tank is essential to a well running fuel system on a vintage Honda. I there is rust or corrosion in the gas tank, take this opportunity to clean it out using our how to video right here.
3. Add a small amount of oil to the new petcock to tank gasket to prevent it from tearing during installation.
4. The mounting nut has reverse threads on the top and bottom, which pull the petcock and tank together to compress the sealing gasket evenly in the center. Start by threading the nut onto both the petcock and tank threads about half a turn. Then tighten the nut onto the tank while holding the petcock still, allowing both parts to meet in the middle.
5. Once finger tight, tighten the nut with a wrench with the petcock facing the correct direction. Do not overtighten and tear the petcock to tank gasket.

In-line filters: We do not recommend using in-line fuel filters on vintage Honda motorcycles. With a clean fuel tank and the built-in petcock filter, debris should not reach the carburetors. Additional in-line filters can restrict fuel flow and may cause running issues, especially above 7,000 RPM.

Frequently Asked Questions

The fuel outlet on the petcock is facing the wrong way. Do you have another version?

This replacement petcock uses a right-side fuel outlet. Although some original Honda petcocks were designed with downward or rear facing outlets, this right exit layout is currently the best and only option for the tight-space fitment required while still delivering the fuel flow needed for models such as the Honda CB750.

Can I rebuild the petcock?

Unfortunately, this petcock is not rebuildable. It uses a riveted front plate design similar to the original Honda Keihin petcock. While other petcocks may thread onto these tanks, we have found they often lack the tight clearance fitment or properly sized internal fuel passages required for these Honda models.

Should I run in-line fuel filters?

No. When the fuel tank is clean and the petcock screen is in place, the system should already protect the carburetors from debris. Extra filters can reduce fuel delivery and may lead to high-RPM performance problems, particularly above 7,000 RPM.

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Last updated: May 2026