Throttle Cable | Honda CB450 / CL450 / CB500T

Description

Throttle Cable for Honda CB450 / CL450 / CB500T

Replacement throttle cable for the Honda CB450 / CL450 / CB500T family. 1-into-2 split design — a single cable runs from the throttle grip and splits into two ends, one for each carburetor. Same family of design as the CB175 / CB200 / CB350 throttle cables, with CB450-specific lengths. Replaces OEM Honda 17910-292-751.

Why You Need This

Your throttle cable is the direct mechanical link between your right hand and the engine. After 50 years, the inner wire stretches unevenly at the split ends, the housing kinks or cracks, and the cable starts dragging inside the housing. The diagnostic test is simple: roll the throttle, let go — the throttle should snap closed like a mousetrap. If it hangs, returns slow, or feels gritty when you work it, the cable is dry, frayed, or both.

On the CB450, both carburetors share one cable through the splitter. A dragging cable on one side prevents the carbs from synchronizing properly and shows up as uneven idle, surging, and the kind of carb-sync chase that never quite ends. New cable in good shape is the prerequisite for a clean carb sync.

Specifications

Important Notes

Carburetor sync is required after install. A new throttle cable changes the slack distribution at the splitter. Plan to bench-sync the carburetors after installing the cable.

Stock length only. If you’ve installed clip-ons, drag bars, high-rise bars, or a relocated throttle housing, the stock cable may be too short or too long. Custom cables from a fabricator are the path for non-stock bar setups.

CB and CL bars route the cable differently. The CB450 uses a semi-raised road bar; the CL450 uses a scrambler bar. Both are covered by the same OEM 17910-292-751 cable — only the routing path differs.

Model-Specific Notes

• CB450 K0 “Black Bomber” (1965–1967): Uses the same throttle cable as later CB450s per Honda OEM 17910-292-751. The K0 has unique pistons, starter, and clutch cable length, but the throttle cable is shared across the K-series.
• CB500T (1975–1976): Mechanically similar to CB450 K7 with the addition of an emissions air-cut valve. Same throttle cable applies.
• CL450 K0–K6: Scrambler bars. Same OEM cable as CB450.

Installation

Difficulty: Beginner to Intermediate. The cable swap is straightforward; the carb sync afterward is the time-consuming part.

Tools needed: Phillips or JIS screwdriver (for the starter switch setting screw on the throttle grip), 8 mm and 10 mm wrenches (jam nuts at the carb adjusters), Marvel Mystery Oil or light machine oil, light grease for the throttle sleeve.

1. Remove the old cable from the carburetors. Note which lower end goes to the left carb and which goes to the right.
2. Disconnect at the throttle grip.: unscrew the setting screw on the starter switch assembly, separate the two halves of the starter switch, expose the cable end, then remove the cable from the throttle grip pipe.
3. Lubricate the new cable before installing. Loop the cable so both ends point up. Drip 15–20 drops of Marvel Mystery Oil into one end. Let gravity pull the oil down the housing. Work the cable back and forth and let it hang for ten minutes. Repeat from the other end.
4. Lubricate the nylon throttle sleeve. Apply a thin layer of light grease to the sleeve and the inside of the throttle housing. A grease-and-oil slurry (light grease thinned with a few drops of Marvel Mystery Oil) coats more evenly than pure grease.
5. Route the new cable. Run from the right-hand switch box, through the bar routing path appropriate for your bike (CB road or CL scrambler), down to the splitter resting near the frame backbone, then to each carburetor.
6. Install the lower ends at the carburetors. Each end seats in its respective carburetor cable adjuster on the top of the slide cap.
7. Set the carb-end slack. Thread each brass adjuster all the way in by hand. Back it out until the slack just disappears — the slide is right at the point of lifting. Add a small amount of slack at each adjuster. Repeat on the other side.
8. Test before riding. Roll the throttle. Let go. The cable should snap shut like a mousetrap. Throttle grip free play should land at 1.3–2 mm (0.04–0.08 in.) at the grip flange, or 10–15° of grip rotation. If it hangs or feels notchy, re-check the lube and the adjuster positions.
9. Sync the carburetors. A new cable changes the slack distribution. Bench-sync both progressive synchronization (slides moving together at all throttle positions) and idle synchronization (slides at the same height at idle). See our CB350 / CB450 carb sync video and KB article below.