Air Filter Cleaning & Replacement Guide for 1998 Yamaha RT100 Dirt Bike

Air Filter Cleaning – Replacement Guide for 1998 Yamaha RT100

The air filter on your 1998 Yamaha RT100 is a critical defender against dust, mud & debris that can harm the engine. Routine cleaning – and eventually replacement – ensures reliable power and longer engine life, especially if you ride off-road.

Why Focus on Your Air Filter?

This model uses a foam air filter designed for easy maintenance. A clean filter prevents dust and dirt from entering the carburetor and engine, reducing wear and ensuring crisp throttle response. Neglect can result in sluggish performance and even costly engine damage.

How to Clean the Air Filter

• Remove the seat: Use the side bolts under the seat to access the airbox.
• Take out the filter: Release the air filter from the airbox mount. Inspect the rubber joint for cracks (– a known wear point on this model–).
• Clean the foam filter: Soak it in a bucket of warm, soapy water. Massage out dirt until the water runs clear. Rinse thoroughly with clean water.
• Dry completely: Air dry the filter away from direct sun and heat.
• Re-oil the filter: Use foam air filter oil – work it into the foam evenly, but avoid excess oil which can restrict airflow.
• Reinstall: Fit the filter into the airbox, making sure it's sealed securely to prevent leaks.

When to Replace the Air Filter

• If you notice tears, thinning foam or crumbling edges, replace with a new filter for full protection.
• If the air filter rubber joint (part number 3A3-14453-02-00) is cracked or hard, replace it to ensure a proper seal.

Unique Notes for 1998 Yamaha RT100 Owners

• The RT100's 1.69 inch (43mm) intake diameter air filter is unique to this bike. Replace with a filter matching these specs for best fit and performance.
• This model's air filter mounts onto a rubber joint between airbox and carburetor. This joint can dry out or crack over time, causing leaks. Inspect this joint every time the filter is serviced.
• Always double-check sealing surfaces—the RT100 is especially sensitive to unfiltered dust due to its two-stroke engine design.

Pro Tips

• Clean your filter after every ride in dusty conditions.
• Keep a spare air filter ready for quick swaps to minimize downtime.

Stay ahead of maintenance to keep your 1998 Yamaha RT100 performing at its best. Shop for air filter replacements, cleaning supplies & more using the MotoSport.com parts page above.

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Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.