CFMoto ATV HX500-S, HX500-L 4x4. Service Manual - part 6

Check the protective boots for holes or tears.
If any damage is found, have them replaced by your dealer.

Removal
1. Remove panel.
2. Remove the spark plug cap.
3. Use the spark plug wrench in the tool kit to remove the 

spark plug as shown.

The spark plug is an important engine component and is easy 
to inspect. The condition of the spark plug can indicate the 
condition of the engine. The ideal color on the white 
insulator around the center electrode is a medium-to-light tan 
color for a ATV/Quadricycle that is being ridden normally. 
Do not attempt to diagnose such problems yourself. Instead, 
take the ATV/Quadricycle to your dealer. You should 
periodically remove and inspect the spark plug because heat 
and deposits will cause the spark plug to slowly break down and erode. If electrode erosion becomes excessive, 
or if carbon and other deposits are excessive, you should replace the spark plug with the specified plug.

Specified spark plug: DPR7EA-9 (NGK)

1. Measure the electrode gap with a wire thickness gauge and, if 

necessary, adjust the gap to specification.

Spark plug gap:0.8

0.9 mm (0.031

0.035 in)

2. Clean the gasket surface. Wipe off any grime from the threads.

3. Install the spark plug and tighten it to the specified torque.

Spark plug tightening torque: 17.5 N

m (1.75 m

kgf, 12.5 ft

lbf)

If a torque wrench is not available when you are installing a spark plug, a good estimate of the 
correct torque is 1/4 to 1/2 turn past finger tight. Have the spark plug tightened to the specified 
torque as soon as possible.

4. Install the spark plug cap.
5. Install the panel.

There is a check hose at the bottom of the air filter case. If dust or water collects in this hose, 

empty the hose and clean the air filter element and air filter case.

1. Remove the seat.
2. Remove the air filter case cover by unhooking the holders.
3. Remove the air filter element.
4. Remove the air filter element from its frame.
5. Wash the air filter element gently but thoroughly in solvent.
6. Squeeze the excess solvent out of the air filter element and 

let it dry.

Do not twist the air filter element when squeezing it.

7. Inspect the air filter element and replace it if damaged.
8. Apply foam air filter oil or other quality foam air filter oil to the air 

filter element. If foam air filter oil is not available, engine oil may 
be used.

The air filter element should be wet but not dripping.

9. Pull the air filter element over its frame.
10. Install the air filter element.
11. Install the air filter case cover and be sure to connect the hose.

12. Install the seat.

 The air filter element should be cleaned every 20

40 hours. It should be cleaned and lubricated 

more often if the machine is operated in extremely dusty areas. Each time air filter element 
maintenance is performed, check the air inlet to the air filter case for obstructions. Check the air 
filter element rubber joint to the carburetor and manifold fittings for an airtight seal. Tighten all 
fittings securely to avoid the possibility of unfiltered air entering the engine.

Never operate the engine with the air filter element removed. This will allow unfiltered air to enter, causing 
rapid engine wear and possible engine damage. Additionally, operation without the air filter element will 
affect carburetor jetting with subsequent poor performance and possible engine overheating.

Be sure the exhaust pipe and muffler are cool before cleaning the spark arrester.
1. Remove the bolts.
2. Remove the tailpipe by pulling it out of the muffler.
3. Tap the tailpipe lightly, and then use a wire brush to remove any carbon deposits from the spark arrester 

portion of the tailpipe.

4. Insert the tailpipe into the muffler and align the bolt holes.
5. Install and tighten the bolts.

When cleaning the spark arrester: Always let the exhaust 
system cool prior to touching exhaust components. Do 
not start the engine when cleaning the exhaust system.

If dust or water collects in the V-belt cooling duct check 
hose, remove the hose and clean it.

After riding in water deep enough to allow it to enter the 
V-belt case, remove this bolt to drain the water from the 
case.

 If water drains from the V-belt case after 

removing the bolt, have your dealer inspect 
the ATV/Quadricycle as the water may affect 
other engine parts, and would be the owner s 

responsibility.

The carburetor is a vital part of the engine and requires very sophisticated adjustment. Most adjusting should be 
left to your dealer who has the professional knowledge and experience to do so. However, the idling speed may 
be performed by the owner as a part of the usual maintenance routine.

The carburetor was set at the factory after many tests. If the settings are disturbed by someone without 
sufficient technical knowledge, poor engine performance and damage may result.

 A diagnostic tachometer must be used for this procedure.

1. Start the engine and warm it up for a few minutes at approximately 1,000 to 2,000r/min. Occasionally rev the 

engine to 4,000 to 5,000 r/min. The engine is warm when it 
quickly responds to the throttle.

2. Remove panel.
3. Connect the tachometer to the spark plug lead, and then set 

the idle to the specified idling speed by adjusting the throttle 
stop screw. Turn the screw in direction     to increase the 
engine speed, and in direction     to decrease the engine 
speed.

 Specified idle speed:1,200

1,400 r/min

4. Install the panel.

The correct valve clearance changes with use, resulting in improper fuel/air supply or engine noise. To prevent 
this, the valve clearance must be adjusted regularly. This adjustment however, should be left to a professional 
service technician.

a

b

Adjust the engine idling speed before adjusting 

the throttle lever free play.

1. Loosen the locknut.
2. Turn the adjusting bolt until the throttle lever free play is 

3

5 mm (0.12

0.20 in).

3. Tighten the locknut.

Check the brake pads for damage and wear.
If a brake pad thickness is less than 2 mm (0.08 in), have 
your dealer replace the pads as a set.

The wheels need to be removed to check the 

brake pads.

Inspect the brake pads for damage and wear.
If the thickness is less than 4 mm(0.16 in), have your dealer 
replace the pads.

Insufficient brake fluid may let air enter the brake system, 
possibly causing the brakes to become ineffective. Before riding, 
check that the brake fluid is above the lower level and replenish when necessary. The front brake fluid master 
cylinder reservoir is located the right of the handlebar. The rear brake fluid master cylinder reservoir is near the 
rear brake pedal.

Observe these precautions:
1. When checking the fluid level,  make sure the top of the master cylinder reservoir is level by turning the 

handlebars.

2. Use only the designated quality brake fluid. Otherwise, the rubber seals may deteriorate, causing leakage and 

poor brake performance.

Recommended brake fluid: DOT3 or DOT 4.

3. Refill with the same type of brake fluid.  Mixing fluids may result in a harmful chemical reaction and lead to 

poor brake performance.

4. Be careful that water does not enter the master cylinder reservoir when refilling.  Water will significantly 

lower the boiling point of the fluid and may result in vapor lock.

5. Brake fluid may deteriorate painted surfaces or plastic parts. Always clean up spilled fluid immediately.
6. Have your dealer check the cause if the brake fluid level goes down.

Complete fluid replacement should be done only by trained service personnel. Have your dealer replace the 
following components during periodic maintenance or when they are damaged or leaking.

 Replace the oil seals every two years.

 Replace the brake hoses every four years.

The front brake lever should have a free play of zero mm (zero in) at the lever end. If not, have your dealer 
check the brake system.

 After servicing:

 Make sure the brakes operate smoothly and that the 

free play is correct.

 Make sure the brakes do not drag.

Make sure the brakes are not spongy.

 All air must be bled from the brake system.

Replacement of brake components requires professional knowledge. These procedures should be performed 
by your dealer.

The rear brake lever free play       should be 0.5

2 mm 

(0.02

0.08 in).

1. Loosen the locknut

.

2. Turn the adjusting bolt

 in direction       to increase 

free play, and in direction         to decrease free play.

3. Tighten the locknut

.

If correct free play cannot be obtained, ask your dealer to 
make that adjustment.

  When adjusting the rear brake lever free play:

 Be sure not to step on the brake pedal.

 Make sure the brake pedal does not move.

 Adjust the rear brake before inspecting the rear brake pads.

a

b

c

The top of the brake pedal should be positioned 72mm (2.8 in) 
above the top of the footrest. If not, ask your dealer to adjust it.

After servicing:

 Make sure the brakes operate smoothly and that the free 

play is correct.

 Make sure the brakes do not drag.

 All air must be bled from the brake system.

Replacement of brake components requires professional knowledge. These procedures should be performed 
by your dealer.

The rear brake light switch, which is activated by the brake 
pedal and brake levers, is properly adjusted when the brake 
light comes on just before braking takes effect. If necessary, 
adjust the brake light switch as follows.

Turn the adjusting nut while holding the rear brake light switch in place. To make the brake light come on 
earlier, turn the adjusting nut in direction     . To make the brake light come on later, turn the adjusting nut in 
direction      .

Inspect cables frequently. Replace damaged cables.

Lubricate the inner cables and the cable ends. If the cables do not operate smoothly, ask your dealer to replace 
them.

 Recommended lubricant: SAE 10W30 motor oil

Lubricate the knuckle upper and lower pivots with a grease 
gun.

Recommended lubricant:

Lithium-soap-based grease

a

b

1. Loosen the wheel nuts.
2. Elevate the ATV/Quadricycle and place a suitable stand under the frame.
3. Remove the nuts from the wheel.
4. Remove the wheel.

1. Install the wheel and the nuts.

 Tapered nuts are used for both the front and rear wheels. Install the 

nut with its tapered side towards the wheel. 

 The arrow        mark on the tire must point toward the rotating direction of the wheel.