Carburetor Insulator Spacer Kit | Honda CT90 / Trail 90 (K0-K6 & 1976-1977)

Carburetor Insulator Spacer Kit | Honda CT90 / Trail 90 (K0-K6 & 1976-1977)

Protect your carburetor and restore proper performance with this CT90 carburetor insulator kit designed to shield the carburetor from excessive heat generated by the cylinder head on your vintage Honda CT90 (K0*, K1-K2 and 1976-1977).

Why You Need This

Many Trail 90s are missing this critical component or are running damaged insulators, which can lead to vacuum leaks, poor idling, and reduced performance. Replacing it ensures a proper seal and smoother operation.

Specifications

Model-Specific Notes

• CT90 "Trail 90" K0*: This carburetor insulator fits Honda CT90 K0 models after SN 188272.

What's in the Kit

• Carburetor insulator spacer
• Carburetor to intake manifold gasket
• Carburetor intake o-ring

Installation

Difficulty: Beginner

Tools needed: Socket Set

1. Remove the carburetor from your CT90 by loosening the nuts that hold it to the intake manifold. Unscrew the top cap holding the carburetor slide and pull out the slide and throttle cable assembly to remove the carburetor from the motorcycle.
2. Remove the original insulator and gasket if they are still in place. Remove any old gasket material from the manifold surface to ensure a proper seal with the new gasket.
3. The carburetor insulator is installed with the gasket in between the insulator and the intake manifold. Install the intake o-ring in the groove of the carburetor, then install the carburetor against the insulator.
4. Reinstall the nuts on the carburetor studs, then reinstall the throttle cable and slide assembly.

Tip: Check for vacuum leaks and throttle cable adjustments after installing to ensure nothing has changed during installation.

Frequently Asked Questions

Do I need this for my CT90?

The carburetor insulator is a commonly missing piece on Trail 90s that should always be installed. The insulator prevents excess engine heat from reaching the carburetor body, which helps prevent fuel vaporization in the float bowl.

Will this fit my CT90 K0?

Most CT90 K0 models use a unique intake manifold with a different carburetor insulator. If your CT90 K0 frame serial number is after SN 188272 then your motorcycle will use this insulator. Keep in mind that these motorcycles have been through 50+ years of ownership, so it's possible that what should be on your motorcycle does not match what is currently installed. Email us if you are unsure.

What is the insulator spacer made of?

The insulator spacer is made of a high temperature thermoplastic to insulate against engine heat.

You Might Also Need

• Complete Replacement Carburetor — If your original carburetor is too rough to rebuild or missing.

Last updated: May 2026