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
| Spec | Detail |
|---|
| Replaces OEM Part Numbers (Gray, early) | 17910-341-000, 17910-300-040, 17920-323-000 |
| Replaces OEM Part Numbers (Black, K3/K4) | 17910-426-610, 17910-404-670, 17920-393-000, 17920-404-670, 17920-410-000 |
| Fits Models | CB500K0/K1/K2 (1971–1973), CB550K0/K1/K2 (1974–1976), CB550F (1975–1977), CB550 K3/K4 (1977–1978) |
| Cable Type | Push/Pull (two separate cables: one opens, one closes) |
| Quantity | Sold as a kit (two cables included) |
| Length — Gray (CB500K, CB550 K0–K2, CB550F) | Pull/Push housing 35″ (890 mm) from bend; end-to-end 39.5″ (1003 mm) |
| Length — Black (CB550 K3/K4) | Push housing 39.5″ (1003 mm) / end-to-end 44.25″ (1124 mm); Pull housing 38″ (965 mm) / end-to-end 44.5″ (1130 mm) |
| Idle Speed Spec | 950–1050 rpm |
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.
- 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.
- Disconnect at the throttle grip housing. Loosen the upper jam nut and slide each cable end out of the throttle pipe.
- 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.
- 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.
- 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.
- 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.
- 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).
- 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.
- 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.
Our 2-part vacuum sync video for the Honda 4-cylinder family covers the full process on a CB550. Part 1 (above) covers what carb synchronization is, when and why to do it, and how to set up the gauges. Part 2 walks through the actual sync end-to-end. Same procedure applies to the CB350F, CB400F, CB500K, CB550, and CB750.
Frequently Asked Questions
I have a 1978 CB550K — which variant do I need?
The black "CB550 K3 / K4" variant. The 1977–1978 CB550K bikes use the longer cable set — pull housing 38″ / 965 mm and push housing 39.5″ / 1003 mm. The shorter gray (early) cables will be 3–4 inches too short. We have customers who learned this the hard way — pick the right variant before checkout.
What's the difference between this kit and a CB360 throttle cable kit?
Same push/pull design, different bike family. The CB360 cable kit fits the 360 family (CB360G, CB360T, CL360, CJ360T). This kit fits the inline-4 family (CB500K, CB550K, CB550F). The push/pull architecture is identical — one cable opens the carbs, one closes them as a fail-safe — but the lengths and cable ends are not interchangeable.
Will this fit my CB500T?
No. CB500T is a 1975–1976 parallel twin in the CB450 family, not the inline-4 CB500K (1971–1973) covered by this kit. CB500T uses a 1-into-2 split throttle cable like the CB450 / CL450 — see our Throttle Cable for Honda CB450 / CL450 / CB500T product.
Why two cables instead of one?
The push cable is a fail-safe. If the pull cable snaps mid-ride, the push cable closes the carb butterflies so the engine doesn't run away on you. Honda added the second cable as a safety feature on the 360 and on every CB four-cylinder. Either cable can fail independently, which is why we sell them as a kit and recommend replacing them together.
Will these work with non-stock handlebars?
Stock-shape replacement bars are usually fine. Clip-ons, drag bars, high-rise bars, or relocated throttle housings can put the cable run out of spec — either too tight or too slack — and you may need custom cables from a fabricator like Motion Pro. Measure your old cables before ordering if you've changed the bar position.
Do I need to sync the carburetors after replacing the cables?
Yes. New cables change the slack distribution between the throttle grip, the linkage, and the carb butterflies. Plan to bench-sync the carbs (slides at the same height at idle) and then vacuum-sync once the engine is at operating temperature. Idle speed should land at 950–1050 rpm. Our CB500K / CB550 / CB750 4-cyl vacuum sync tool kit pairs with this kit.
How do I know if my throttle cables are actually the problem?
Roll the throttle and let go. A good cable pair returns the throttle instantly — snaps shut like a mousetrap. A worn pair hangs, drags, or returns slowly. Visual signs: bent or squashed barrel ends, rusty wire poking out of the housing, frayed strands at the barrel, cracked or chewed housing. If you see any of those on either cable, replace the pair.
How often should I lubricate these cables?
Lubricate before installing — cables ship dry from the factory. After that, an annual lube during your spring tune-up keeps things smooth. If the throttle starts feeling gritty or returning slowly, it's time to lube again. The U-loop method with Marvel Mystery Oil takes about ten minutes per cable.
You Might Also Need
Last updated: May 2026
