Kymco MO KXR 250 Service Manual - chap 13 (freni)

13. BRAKE SYSTEM

13-0

Mongoose/KXR 250

13

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BRAKE SYSTEM

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SERVICE INFORMATION -------------------------------------------- 13- 2

TROUBLESHOOTING ------------------------------------------------- 13- 3

FRONT BRAKE FLUID CHANGE/AIR BLEED -------------------- 13- 4

BRAKE MASTER CYLINDER ----------------------------------------- 13- 5

FRONT BRAKE CALIPER--------------------------------------------- 13- 8

REAR HYDRAULIC BRAKE------------------------------------------ 13-11

REAR BRAKE MASTER CYLINDER (REAR BRAKE PEDAL) ---- 13-13
REAR BRAKE CALIPER ---------------------------------------------- 13-16

13

13. BRAKE SYSTEM

13-1

Mongoose/KXR 250

13. BRAKE SYSTEM

13-2

Mongoose/KXR 250

SERVICE INFORMATION

GENERAL INSTRUCTIONS

• During servicing, keep oil or grease off the brake pads and brake disk.

• Drain the brake fluid from the hydraulic brake system before disassembly.

• Contaminated brake disk or brake pads reduce stopping power. Clean the contaminated brake

disk with high-performance brake degreaser and replace the brake pads.

• Do not use brake fluid for cleaning.

• Bleed air from the brake system if the brake system is removed or the brake is soft.

• Do not allow any foreign matters entering the brake reservoir when filling the brake reservoir with

brake fluid.

• Brake fluid will damage painted, coated surfaces and plastic parts. When working with brake

fluid, use shop towels to cover and protect painted, rubber and plastic parts. Wipe off any splash
of brake fluid with a clean towel. Do not wipe the machine with a towel contaminated by brake
fluid.

• Make sure to use recommended brake fluid. Use of other unspecified brake fluids may cause

brake failure.

• Inspect the brake operation before riding.

SPECIFICATIONS

Item

Standard (mm)

Service Limit (mm)

Brake disk thickness

3.8_ 4.2

3.0

Brake disk runout

æ

0.30

TROUBLESHOOTING

Loose brake lever Tight brake lever

• Air in hydraulic brake system •Seized piston

• Brake fluid level too low •Clogged hydraulic brake system

• Hydraulic brake system leakage •Smooth or worn brake pad

Poor brake performance Brake noise

• Air in brake system • Contaminated brake pad surface

• Deteriorated brake fluid • Excessive brake disk run out

• Contaminated brake pads and brake disk • Incorrectly installed caliper

• Worn brake pads • Brake disk or wheel not aligned

• Worn brake master cylinder piston oil seal

• Clogged brake fluid line Hard braking

• Deformed brake disk •Seized hydraulic brake system

• Unevenly worn brake caliper •Seized piston

13. BRAKE SYSTEM

13-3

Mongoose/KXR 250

FRONT HYDRAULIC BRAKE

BRAKE PADS REMOVAL

Remove the front wheel. (!14-3)

Remove the two brake pad pins from the
brake caliper.

Remove the two bolts attaching the brake
caliper and then remove brake caliper.

Compress the brake caliper holder and
remove brake pads.

A wear indicator is provided on each brake.
The indicators allows checking of brake
pads wear. Check the position of the
indicator.

BRAKE DISK

Measure the brake disk thickness.
Service Limit: 3.0mm
Measure the brake disk run out.

Service Limit: 0.3mm

INSTALLATION

Reverse the “BRAKE PADS REMOVAL”
procedures.

13. BRAKE SYSTEM

13-4

Mongoose/KXR 250

FRONT BRAKE FLUID
CHANGE/AIR BLEED

BRAKE FLUID DRAINING

Place the machine on the level ground and
set the handlebar upright.
Remove the two screws attaching the brake
fluid reservoir cap.

Connect a transparent hose to the brake
caliper bleed valve and then loosen the bleed
valve nut.
Use a syringe to draw the brake fluid out
through the hose.

BRAKE FLUID REFILLING

Connect a transparent hose and syringe to
the brake caliper bleed valve and then loosen
the bleed valve nut.
Fill the brake reservoir with brake fluid and
use the syringe to draw brake fluid into it
until there is no air bubbles in the hose.
Then, tighten the bleed valve nut.

Torque: 0.4_ 0.7kg-m

Recommended Brake Fluid: DOT-4

Use shop towels to cover plastic parts
and coated surfaces to avoid damage
caused by splash of brake fluid.

°Ø

• When drawing brake fluid with the

syringe, the brake fluid level should be
kept over 1/2 of the brake reservoir
height.

• Use only the recommended brake fluid.

°Ø

13. BRAKE SYSTEM

13-5

Mongoose/KXR 250

BRAKE SYSTEM BLEEDING

Connect a transparent hose to the bleed
valve and fully apply the brake lever after
continuously pull it several times. Then,
loosen the bleed valve nut to bleed air from
the brake system. Repeat these steps until
the brake system is free of air.

BRAKE MASTER CYLINDER

DISASSEMBLY

Remove the brake reservoir cover
Drain the brake fluid from the hydraulic

brake system. (!13-4)

Remove fluid tube bolt and then disconnect
the fluid tube.

Disconnect the stop light switch wires.

Remove the two master cylinder holder
bolts and remove the master cylinder.

Do not splash brake fluid onto any
rubber, plastic and coated parts. When
working with brake fluid, use shop
towels to cover these parts.

°Ø

When removing the brake fluid tube bolt,
be sure to place towels under the tube
and plug the tube end to avoid brake fluid
leakage and contamination.

°Ø

When bleeding air from the brake system,
the brake fluid level should be kept over
1/2 of the brake reservoir height.

°Ø