[CFMoto ZForce 800 CVT, Drive Belt & Clutch Troubleshooting Guide]

CFMoto ZForce 800 CVT, Drive Belt & Clutch Troubleshooting Guide

This guide is a starting point for diagnosing CVT, drive-belt, clutch and acceleration problems on the CFMoto ZForce 800, 800EX and 53" Trail.

Common symptoms include:

• Jerky acceleration from a stop
• Belt squealing or chirping
• Rattling from the CVT area
• Loss of top speed
• Poor low-speed performance
• Belt damage after mud or water exposure
• Premature belt wear
• Clutch engagement problems

The ZForce 800 drivetrain is different from some other side-by-side CVT systems because many ZForce 800 models use a centrifugal wet clutch in addition to the primary and secondary CVT clutches.

Before buying parts, determine whether the problem is coming from the drive belt, CVT clutches, wet clutch or another drivetrain component.


1. HOW THE ZFORCE 800 CVT & WET CLUTCH WORK

Many ZForce 800 models use a centrifugal wet clutch behind the CVT primary clutch.

The wet clutch begins transferring engine power to the CVT as engine RPM increases. Because of this design, the drive belt normally remains under tension rather than acting exactly like the belt on some conventional snowmobile-style CVT systems.

This design can reduce belt slipping during low-speed engagement, but it also means that jerky takeoff or poor engagement can involve either the CVT system or the wet clutch.

Related discussion:

How the ZForce 800 Wet Clutch Works


2. WHICH DRIVE BELT SHOULD I USE?

ZForce 800 owners have discussed OEM and aftermarket belts extensively.

Commonly discussed options include:

• OEM Bando belts
• OEM Mitsuboshi belts
• Gates belts
• Gates Carbon belts
• Ultimax belts
• EPI Severe Duty belts

For early ZForce 800 models, owners have commonly discussed Gates part numbers in the 40G3691 / 40C3691 family.

The Gates "C" carbon belt has generally been discussed as the heavier-duty option compared with the "G" version.

However, belt fitment can vary by model year and machine configuration.

Always verify the correct belt part number for your exact model year before ordering.

Related discussions:

Which CVT Belt for the ZForce 800?

Need a Belt for ZForce 800

ZForce 800 OEM Belt Discussion


3. OEM VS. AFTERMARKET BELTS

Forum members have reported mixed results with aftermarket belts.

Factors that affect belt life include:

• Machine weight and load
• Mud and sand use
• Steep climbing
• High ambient temperatures
• CVT airflow and cooling
• Clutch condition
• Driving style

OEM belts are often more expensive, but several owners have reported long service life from the factory Bando or Mitsuboshi belts.

Aftermarket belts can be a reasonable option, but the least expensive belt is not always the best value.

If your machine sees heavy loads, mud, sand or frequent hill climbing, choose a belt intended for heavier-duty use.


4. JERKY ACCELERATION FROM A STOP

If the machine accelerates smoothly once moving but jumps, jerks or shudders when starting from a stop, inspect both the belt/CVT system and the wet clutch.

Possible causes include:

• Burned or damaged drive belt
• Glazed belt surfaces
• Contaminated clutch surfaces
• Wet-clutch wear or damage
• Primary or secondary clutch problems
• Incorrect clutch setup

A jerky takeoff is not considered normal.

Related discussion:

ZForce 800 Jerky Acceleration From a Stop


5. BELT SQUEALING AFTER WATER OR MUD

Water, mud and debris entering the CVT housing can cause belt squeal, slipping and accelerated wear.

If the belt begins squealing after deep water or mud exposure:

• Allow the CVT housing to drain and dry
• Inspect the belt for glazing or damage
• Inspect the clutch sheaves for contamination
• Check the CVT intake and exhaust ducting
• Verify the CVT housing drain system is clear

If the belt has been overheated or severely glazed, replacement may be necessary even if it is not visibly broken.


6. LOSS OF TOP SPEED

A noticeable reduction in top speed can sometimes indicate belt wear.

As a belt wears narrower, the CVT may no longer reach the same effective drive ratio.

Also inspect:

• Belt width and condition
• Primary clutch movement
• Secondary clutch movement
• Clutch sheave wear
• Engine performance

Do not assume every top-speed problem is caused by the belt. Engine power loss, fuel problems or other drivetrain issues can produce similar symptoms.

Related discussion:

ZForce 800 Belt Wear & Top-Speed Discussion


7. CVT BELT RATTLE OR NOISE

Some owners have reported rattling or unusual noises from the CVT area, particularly during deceleration or at lower RPM.

Inspect:

• Drive belt condition
• Belt clearance inside the CVT housing
• Primary clutch hardware
• Secondary clutch hardware
• Clutch sheaves
• CVT cover and internal contact marks

Any new or severe noise should be investigated before continued riding.

Related discussion:

ZForce 800 CVT Belt Rattling Discussion


8. SECONDARY CLUTCH SETTINGS

Owners have experimented with secondary-clutch spring settings to change low-speed response and acceleration characteristics.

One commonly discussed setup for earlier ZForce 800 machines is the B2 position, which members have described as a good overall setting for stronger low-end response without sacrificing normal top speed.

Do not change clutch settings unless you understand how the adjustment affects belt pressure, engagement and drivetrain load.

Incorrect clutch setup can increase belt heat and wear.

Related discussion:

ZForce 800 CVT Clutch Settings Discussion


9. WET CLUTCH PROBLEMS

The wet clutch is located behind the primary CVT assembly and requires significantly more disassembly to access than a normal belt inspection.

Possible wet-clutch symptoms can include:

• Jerky engagement
• Poor takeoff
• Slipping under load
• Abnormal engagement behavior

Because wet-clutch inspection requires deeper engine-side disassembly, first eliminate simpler causes such as the belt and external CVT components.

Related discussion:

ZForce 800 Wet Clutch Inspection Discussion


10. SHOULD I CARRY A SPARE BELT?

Carrying a spare belt can be useful, especially for long-distance or remote riding.

However, changing a ZForce 800 belt trailside can require more tools and time than on some other machines.

Consider carrying:

• Correct spare belt
• Required hand tools
• Clutch-removal or spreading tools as applicable
• Torque wrench if practical

Before relying on a trailside repair, practice the belt-change procedure at home.

Related discussion:

Should You Carry a Spare ZForce 800 Belt?


11. BEFORE POSTING A CVT OR CLUTCH QUESTION

Include as much of the following information as possible:

• Model year
• Exact model: 800, 800EX, 53" Trail, EPS, etc.
• Mileage and operating hours
• Current belt brand and part number
• Approximate mileage on the belt
• Whether the machine has been used in mud or deep water
• Whether the problem occurs only from a stop or at all speeds
• Any squealing, rattling or other noises
• Current clutch settings or modifications
• Any recent clutch or belt repairs

Photos of the belt, clutch sheaves and CVT housing can be very helpful.


RELATED ZFORCE 800 RESOURCES

CFMoto ZForce 800 Resources: Manuals, Maintenance & Troubleshooting

CFMoto ZForce 800 Won't Start or Hard to Start – Troubleshooting Guide

CFMoto ZForce 800 Overheating & Radiator Fan Troubleshooting Guide

CFMoto ZForce 800 Owner's Manual PDF


Have a CVT, belt or clutch problem not covered above?

Start a new topic in the ZForce 800 section and include the information from the checklist above. Describe exactly what the machine does from a stop, at cruising speed and under load.