Throttle Cable | Honda CT90 / Trail 90

Throttle Cable | Honda CT90 / Trail 90 (K0-K6 & 1976-1979)

Replacement Throttle Cables for Honda CT90 - "Trail 90" Motorcycles

Why You Need This

Throttle cables provide a direct connection between you and your motorcycle's engine, which is why it is crucial they remain in top shape. Over time, they can become frayed, sticky or rusted stuck inside the housing - this is especially true on older bikes, like a vintage Honda Trail 90. The throttle on your Honda CT90 should turn easily and actuate the carburetor slide with minimal friction. If not, it is time to replace the cable and lube the throttle mechanism.

Our high quality throttle cables make the replacement simple, restoring smooth operation on your vintage Honda CT90. Be sure to select the one that fits your specific "K" series when adding it to the cart.

Specifications

Note: These cables do not come with the internal throttle cable handlebar grommet - be sure to select the optional add-on, if yours is missing.

Installation

Difficulty: Beginner

Tools needed: JIS screwdrivers

1. Remove the CT90 plastic body cover to get access to the entire cable.
2. Unscrew the top of the carburetor and remove the existing cable along with the attached carburetor slide and needle mechanism. Remove the cable from the slide components by pressing the inner cable wire further into the slide so that the cable ferrule end extends from the bottom and can be removed through the larger end of the key shaped opening in the slide body. Sit throttle slide and spring to the side for install on the new cable.
3. Use a JIS screwdriver to unscrew the right handlebar switch box to gain access to the throttle mechanism and cable.
4. If your CT90 is an early K2 - K5 model that uses the internal handlebar style throttle, tape the end of the new throttle able to the old one and use it to pull the cable through the handlebars. Transfer the throttle cable grommet to the new cable if reusing original grommet. On later trail 90s, the throttle cable can just be unscrewed from the bottom of the switch box.
5. Install the new throttle cable be reversing these steps. Reinstall the bottom of the throttle cable into the throttle spring and then slide. Properly route the throttle cable into the throttle tube mechanism according to the instructions in the Honda service manual.
6. Before bolting the handlebar switch back together, clean and lubricate the throttle tube and mechanism with fresh lube. At CMC, we recommend wheel bearing grease that has been thinned down with a thin oil, like marvel mystery oil.
7. Properly route the cable through the center of the triple tree and around the left side of the motorcycle to the carburetor before reinstalling the throttle slide.
8. Adjust the freeplay in the throttle cable using the adjuster on the top of the carburetor. The throttle tube needs 1/8-1/4" (3-6mm) of free play before the throttle is pulled.
9. Once freeplay is set and the throttle opens and closes smoothly, reinstall the plastic body cover.

All new cables will need to be lubricated before installation. A quality motorcycle cable lube or marvel mystery oil works great.

Early internal handlebar throttle mechanisms - These early mechanisms have a lot of moving pieces and friction surfaces. Before lubricating the mechanism, fine tune the metal slide inside the handlebar with a small amount of sandpaper so that it slides smoothly in both the handlebar channel and the internal spiral groove in the metal throttle tube. Even when perfectly set, the throttle often will not snap back like a later mechanism using the plastic throttle tube.

Watch our Cables 101 video for more information on cable installation and care.

Frequently Asked Questions

Do you sell throttle tubes?

If you have a CT90 K6 and later, we sell replacement throttle tubes right here. We do not have replacements for early models that use the internal handlebar throttle mechanism. If you are missing parts of your internal throttle mechanism, you will need to find used replacements or switch to the later external style throttle mechanism.

Does the cable need to be lubricated?

All new cables will need to be lubricated before installation and every 3,000 miles (5,000 km). A quality motorcycle cable lube or marvel mystery oil works great.

You Might Also Need

• Honda Nylon Throttle Tube | Honda CT90 / Trail 90 (K6-K9) — Replace if worn out or missing.
• Handlebar Grips — Replace if worn out or changing styles
• JIS Screwdrivers — Designed to remove factory Honda screws without destroying them

Last updated: June 2026