How to Bleed and Replace Brake Fluid on a 2017 Kymco MXU 450i

Shop parts for a 2017 Kymco MXU 450i ATV.

This MotoSport-exclusive service guide walks you through safely replacing and bleeding the brake fluid on a 2017 Kymco MXU 450i (MMY). Follow each step exactly, use the correct fluid, and respect safety warnings to keep braking performance reliable off-road.

What you need

  • DOT 4 brake fluid (do not mix with DOT 5 silicone)
  • Clean funnel or fluid transfer bottle
  • Clear plastic tubing that fits over bleed nipples
  • Catch bottle for old fluid
  • Hand or vacuum brake bleeder (optional but recommended)
  • Box or open-end wrenches to fit bleed nipples (check your bike for exact size)
  • Brake cleaner, rags, gloves, eye protection
  • Service manual or torque specs for banjo bolts/bleeder bolts
  • Jack or stands to lift wheels off the ground (if you plan to actuate calipers)

Notes specific to the 2017 Kymco MXU 450i

  • The MXU 450i uses hydraulic disc brakes; ensure you locate both master cylinder reservoirs (front/master on the handlebar and a separate rear reservoir if equipped) before beginning.
  • Some MXU 450i units have a combined master with a separate rear proportioning setup; visually confirm reservoir positions and fluid level sensors before removing caps.
  • Banjo bolt and bleeder torque specs vary by model year; if you don't have the exact torque, snug hardware to manufacturer feel and check the service manual or a MotoSport tech for exact values.
  • Use DOT 4 for best temperature performance and compatibility with OEM seals used on the MXU 450i.

Preparation

  1. Park on level ground, engage park/gear, and disconnect battery negative terminal if you'll be working extensively around the master cylinder.
  2. Clean the area around reservoir caps to prevent contamination. Remove seat/panels as needed to access reservoirs.
  3. Wear gloves and eye protection. Brake fluid damages paint and plastics; protect surfaces and immediately wipe spills with brake cleaner.
  4. Open the reservoir cap(s) slowly; cover openings with clean lint-free cloth to minimize contamination and allow old fluid to settle.

Drain old fluid from reservoir

  1. Use a turkey baster or fluid transfer bottle to remove as much old fluid from the reservoir as possible. Dispose of old fluid properly.
  2. Top the reservoir with fresh DOT 4 fluid to the recommended level; do not overfill.

Bleeding sequence

Always bleed starting with the caliper furthest from the master cylinder and proceed to the nearest. Typical sequence on ATVs is:

  • Right rear (if applicable) – furthest
  • Left rear
  • Right front
  • Left front – nearest

Confirm which caliper is furthest on your specific MXU layout before starting.

Manual vacuum or pressure bleed method

  1. Fit clear tubing onto the caliper bleeder nipple and place the other end in a catch bottle partially filled with old fluid (to prevent air intake).
  2. Crack the bleeder nut about a quarter turn. Have an assistant slowly squeeze the brake lever/pedal until fluid flows into the tubing with no air bubbles, then close the bleeder while pressure is applied. Repeat until only clear fluid appears.
  3. Keep reservoir topped with fresh DOT 4 to avoid sucking air into the master.
  4. Repeat at each caliper following the bleed sequence.

One-person vacuum or pressure method (recommended)

  1. Attach a vacuum pump to the bleeder tubing or use a pressurized master reservoir kit. Pump until fresh fluid flows without bubbles, close bleeder, and move to next caliper.
  2. Vacuum methods reduce the chance of introducing air when performed alone and are cleaner.

Bench and system checks

  1. After bleeding each caliper, verify firm lever/pedal feel. If spongy, repeat bleeding until firm.
  2. Ensure bleeder nuts are tightened to the correct spec (or snug if spec unknown) and banjo bolts are torqued per manual.
  3. Top reservoir to correct level, reseal caps, and clean any fluid residue from surfaces.
  4. Pump lever/pedal several times with bike on stands and confirm no leaks.
  5. Lower ATV, perform low-speed brake tests in a safe area to confirm braking performance before riding hard.

Maintenance tips & replacement intervals

  • Change brake fluid every 12 to 24 months or sooner if contaminated or if braking feels inconsistent.
  • Always use fresh DOT 4 from a sealed container. Avoid partial open bottles stored for long periods.
  • Inspect lines, hoses, banjo fittings, pads, and rotor condition while working. Replace cracked hoses or worn pads immediately.
  • Record service dates in your maintenance log to maintain resale value and safety.

Disposal and safety

  • Dispose of used brake fluid per local hazardous-waste regulations; do not pour down drains.
  • If brake fluid contacts paint or plastics, rinse immediately with water and clean with brake cleaner to prevent damage.

If you need parts or bleeder kits specifically chosen for the 2017 Kymco MXU 450i, use the MotoSport parts link above to find master cylinder caps, bleeder kits, DOT 4 fluid, banjo hardware, and hoses that fit your ride.

Related Shopping Categories

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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.