Throttle Cable Kit | Honda CB500K / CB550K / CB550F

Description

Throttle Cable Kit for Honda CB500K / CB550K / CB550F

Replacement push/pull throttle cable kit for the Honda 4-cylinder family. Two cables in the kit — one pulls the carburetors open, one pulls them closed. Pick the variant that matches your bike: the early gray cables fit CB500K (1971–1973), CB550K0–K2 (1974–1976), and CB550F (1975–1977); the longer black cables fit CB550 K3 / K4 (1977–1978).

Why You Need This

Your throttle cables are the direct mechanical link between your right hand and the engine. After 50 years, the inner wires stretch, the housings kink or crack, and the cables start dragging inside their housings. 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, one or both cables are dry, frayed, or both.

On the CB500K and CB550, both cables work as a pair. The pull cable opens the carb butterflies when you twist the throttle. The push cable is Honda’s fail-safe — if the pull cable snaps, the push cable yanks the butterflies closed so the engine doesn’t run away. Honda used this push/pull architecture on the CB360 and on every CB four. If one cable is broken, the other is on its way out. Always replace as a pair.

Specifications

Important Notes

Pick the variant that matches your bike. The kit is sold as one of two configurations — gray cables (early) or black cables (CB550 K3/K4). The longer K3/K4 set will not fit a CB500K0; the shorter early set will run too tight on a 1978 CB550K. Match your year and model when you select.

Replace as a pair. If one cable is bad, the other is close behind. The push cable doesn’t get the daily wear the pull cable does, but they’re the same age and they age the same way.

Carburetor sync is required after install. A new pair of cables changes the slack distribution at the throttle linkage. Plan to bench-sync the carburetors, then vacuum-sync once the engine is running — we have a full 2-part video walkthrough below.

Stock length only. If you’ve installed clip-ons, drag bars, high-rise bars, or relocated the throttle housing, neither variant may be the right length for your build. Custom cables from a fabricator are the path for non-stock bar configurations.

Model-Specific Notes

• CB500K (1971–1973) is the four-cylinder, NOT the CB500T twin. CB500K is the inline-4 ancestor of the CB550. CB500T is a 1975–1976 parallel-twin in the CB450 family — this kit does NOT fit the CB500T. If you have a CB500T, see our CB450 / CL450 / CB500T throttle cable.
• CB500K (1971–1973), CB550K0–K2 (1974–1976), CB550F (1975–1977): Use the gray (early) variant. Standard length cables.
• CB550 K3 / K4 (1977–1978): Use the black (late-K) variant. Longer cables to match the late-K bar position.
• Carb generation note: The 4-cylinder Hondas split into “early style” (1975 and earlier — no reference carb, all four individually adjustable) and “late style” (1976 and later — one carb is the reference, the other three adjusted to it). The longer cable variant typically pairs with the late-style sync procedure.

Installation

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

Tools needed: Phillips or JIS screwdriver, 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 cables from the throttle linkage on top of the carburetors. Note which cable end goes to the pull side and which to the push side. Photograph the linkage before disconnecting if you’ve never seen this design before.
2. Disconnect at the throttle grip housing. Loosen the upper jam nut and slide each cable end out of the throttle pipe.
3. Lubricate both new cables before installing. For each cable: loop it so both ends point up. Drip 15–20 drops of Marvel Mystery Oil into the upper end. Let gravity pull the oil down the housing. Work the cable back and forth, hang for ten minutes, repeat from the lower end. A dry cable feels stiff and won’t snap shut properly.
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 cables. Both cables run from the throttle grip down through the headlight area and into the throttle linkage on top of the carburetors. Keep the routing free of sharp bends and frame interference.
6. Connect at the linkage. Each cable end seats in its position on the throttle linkage drum. The pull cable attaches to the side that pulls the linkage open when you twist the throttle. The push cable attaches to the side that pulls the linkage closed.
7. Set the slack.: leave roughly 3 mm (0.12 in) of adjustment range at the cable adjuster for final micro-adjustment. The throttle lever / eccentric pin (overtravel stopper) clearance should sit at 2–3 mm (0.08–0.12 in).
8. Test before riding. Roll the throttle. Let go. The throttle should snap closed like a mousetrap. If it hangs, re-check the cable lube and the adjuster slack. If it feels notchy, check the throttle sleeve grease.
9. Sync the carburetors. A new pair of cables changes the linkage slack. Bench-sync first (slides at the same height at idle), then vacuum-sync at idle (950–1050 rpm) using a CMC 4-cylinder vacuum sync kit or equivalent. Our 2-part video covers the full process — see below.