How to Change Brake Pads on a 1999 Yamaha RT100 Dirt Bike

Shop parts for a 1999 Yamaha RT100 Dirt Bike.

Brake System Overview

The 1999 Yamaha RT100 uses a hydraulic disc brake system common to many small-displacement trail and youth dirt bikes. Key components you'll encounter are the brake lever or pedal, master cylinder, braided or rubber hydraulic line, brake caliper, brake pads, and a steel rotor. When you pull the lever or press the pedal, hydraulic pressure pushes the caliper pistons so the brake pads clamp the rotor and slow the bike.

When to Replace Brake Pads on Your RT100

  • Reduced braking power or longer stopping distances.
  • Squealing, chirping, or grinding noises when braking.
  • Excessive lever or pedal travel before engagement.
  • Visible pad material worn down close to the backing plate.
  • Heat discoloration or scoring on the rotor indicating pad breakdown.

Inspect pads frequently after muddy rides or heavy trail use. On a small-displacement machine like the RT100, pads wear faster with aggressive downhill or repeated heavy braking.

Tools & Supplies

  • Basic metric socket and wrench set
  • Needle-nose pliers and small flat screwdriver
  • C-clamp or piston compressor tool
  • Clean rags and brake cleaner (or isopropyl alcohol)
  • Replacement brake pads specific to 1999 Yamaha RT100
  • Small container for retaining pins or clips

Step-by-Step: Change Brake Pads on the RT100

  1. Prepare the bike and workspace. Park the RT100 on a level surface, remove the key, and ensure the engine is cool. Work in a clean, well-lit area with a tray for small parts.
  2. Support the bike securely. Use a center or rear stand to lift the bike so the wheel can turn freely. If you don't have a stand, block the bike so it won't tip while you remove components.
  3. Decide whether to remove the wheel. Many RT100 caliper designs allow pad change with the wheel in place; if access is tight, remove the wheel first by loosening axle nuts and sliding out the axle. Removing the wheel gives better access to the caliper and rotor for inspection.
  4. Locate and remove the retaining pin or clip. Find the pad retaining pin(s) or spring clip on the caliper. Use pliers or a screwdriver to remove the clip, then slide the retaining pin out. Keep small parts in a container.
  5. Extract the old pads. Pull the pads out of the caliper carrier. They may be held by a spring plate; note the orientation so you install new pads the same way.
  6. Inspect rotor & caliper. Check the rotor for deep grooves, heat discoloration, or warping. Look inside the caliper for debris, stuck pistons, or fluid leaks. Clean the area with a rag and brake cleaner.
  7. Compress the piston(s). Before installing new thicker pads, compress the caliper piston(s) back into the bore so the pads will fit. Use a C-clamp or piston tool with a clean block of wood or pad backing plate between the piston and clamp to protect surfaces. Compress slowly until fully seated.
  8. Install the new pads. Slide the new RT100 pads into the caliper in the same orientation as the old pads. Ensure the friction material faces the rotor and any shim plates or springs are positioned correctly.
  9. Reinstall retaining hardware. Replace the pin and clip, making sure they are fully seated and secure. If your caliper uses a bolt instead of a pin, torque to the specified snugness without over-tightening.
  10. Reinstall the wheel (if removed). Slide the axle back through, align spacers, and torque axle nuts to proper fit. Spin the wheel to check for rotor rubbing and that the rotor clears caliper components.
  11. Restore hydraulic pressure. Pump the brake lever or pedal several times until you feel firm resistance. This moves the new pads into contact with the rotor. Check for any abnormal movement or fluid seepage.
  12. Final check. Verify that pad retaining hardware is secure, lever feel is normal, and the wheel spins freely without excessive drag.

Helpful Inspection Tips While You Work

  • Measure rotor thickness visually – excessive thinning or heavy scoring suggests rotor service or replacement.
  • Look for fresh brake fluid around the caliper or hose ends that could indicate a leak.
  • Ensure caliper slides (if applicable) move freely on their pins – seize here causes uneven pad wear.
  • Clean mud and grit out of the caliper bracket and around the piston to prevent contamination of the new pads.
  • Confirm the retaining pin and spring are not bent and sit fully engaged in the caliper slots.

Bedding In New Brake Pads

Bedding pads helps them mate with the rotor for consistent bite. After installation, perform 8–12 moderate stops from low speed to gradually heat the pad surface, then several firmer stops to set the pad material. Avoid repeated hard stops from high speed on the first rides. Check lever feel again and re-torque axle hardware after the first short ride.

Notes on 1999 RT100 Braking Characteristics

The RT100 is a lightweight, youth-oriented 100cc trail bike where braking demands are lower than full-size motocross machines, but good pad condition still matters for control on steep or technical trails. Most modern dirt bikes including the RT100 use hydraulic disc brakes with a caliper squeezing pads against a steel rotor. If your RT100 shows unusual rotor size or caliper differences from other years, adjust access and tools as needed when removing hardware.

Regular pad inspections and timely replacement keep braking predictable and maintain confident control on trail and practice sessions. With basic tools and these steps, you can refresh the RT100's stopping performance in your own garage.

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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.