How to Replace the Belt on Bikes

by Contributing WriterUpdated June 12, 2017

Scooters have the benefit of requiring very little maintenance, allowing their owners to travel freely without worry. However, some items will need eventual replacement over time. While most wear-and-tear components, such as spark plugs and air filters, are easily replaced, changing your scooter's worn out drive belt can appear to be quite a challenge. But don't be intimidated: the actual process is much easier than it appears and often takes less than a half hour to complete. Best of all, you will only need a few hand tools.

Under The Hood:

 How to Replace the Belt on a Scooter

Park your scooter on its center stand and remove the belt cover from the motor using a socket wrench.

Locate the rear wheel's "driven" pulley and pull the outer half towards you. This will separate the pulley and release the tension on the drive belt. Follow the belt to the "drive" pulley on the motor. Push the inner half of the pulley against the motor to release the drive belt. Pull the belt completely off both of the pulleys.

Separate the driven pulley by pulling the halves apart then slip the replacement drive belt between the halves. Work the belt into place using a rocking motion until the belt is seated against the bottom of the pulley halves. Pull the free end of the drive belt over the drive pulley and center it between the pulley halves. The belt will be loosely fitted over the pulley at this time. Pull the belt by hand to ensure that the belt and pulleys move freely.

Turn your scooter's ignition switch on and start the motor. As the motor begins to spin, the pulleys will automatically tighten the drive belt. Stop the motor and reinstall the belt cover.

Items you will need

  • Socket set

  • Socket wrench

  • Replacement CVT belt

 How to Replace the Belt on a 600 Grizzly

Park your Yamaha 600 Grizzly on a bike lift and use the brakes to stabilize the motorcycle. Raise the bike lift so that the body of the motorcycle is at your shoulder level.

Remove the engine cover with a ratchet set located on the left side of your 600 Grizzly. Keep the bolts you have removed in a safe area where you can retrieve it later on.

Locate the grey-colored wheel securing the drive belt in place, called the sheeve wheel. Turn the sheeve wheel clockwise until the wheel becomes loose within the sheeve wheel bay.

Remove the old drive belt and discard. Take the replacement belt and place it back into the sheeve wheel. Ensure the tread is facing inward.

Turn the sheeve wheel counterclockwise until you hear a "click." This sound indicates the belt and wheel have been locked back into position. Replace your engine cover and lower the bike onto the ground.

Items you will need

  • Ratchet set

  • Bike lift

  • Replacement Grizzly 600 belt

 How to Change a Belt on a Yamaha Grizzly

Drive the Yamaha Grizzly onto the bike lift, then apply the brake. Raise the lift so that the side of the Grizzly is shoulder level. Use the ratchet set to remove the engine cover on the left side of the Grizzly.

Set up the shop light so that the engine is well lit. Turn the right-hand-side sheeve wheel (the grey wheel holding the drive belt in place) clockwise as firmly as possible. Continue turning until the wheel is loose in the sheeve wheel bay.

Slip the old drive belt off the sheeve wheel and discard it. Place the new replacement belt, tread facing inward, on the track of the left stable sheeve wheel. Pull the slack of the belt around the loose, right-side sheeve wheel.

Turn the right sheeve wheel counterclockwise very firmly until you hear a "click" sound, indicating it has locked into position. Replace the engine cover and tighten it back into place with the ratchet set. Lower the bike lift to the ground.

Items you will need

  • Ratchet set

  • Replacement belt

  • Bike lift

  • Shop light

 How to Replace the Belt on a Kawasaki Mule

Find your owner's manual or contact your local Kawasaki dealer to determine which type of special pulley tool your Mule needs for you to remove the drive pulley from the engine.

Loosen the bolts on the converter cover with a wrench, socket or screwdriver, depending on the model of Mule you own. Lift the cover off carefully and see if there are any wires connected to the cover itself. Disconnect them if there are. Place the cover to the side.

Remove the drive pulley by loosening the three upper bolts that protrude up from it, using a socket or wrench. Slot the pulley tool over the drive pulley nut and turn it counterclockwise to remove it. Slide the belt off with a flat-head screwdriver.

Install the new belt and replace the drive pulley nut. Check the deflection of the belt by placing a straight edge from the drive pulley to the driven pulley and push down on the belt in between. There should be no more than 1 inch of deflection. If there is more, you will need to add or subtract shims from the pulley, which must be done by a licensed Kawasaki mechanic using specialized tools. Reverse the process to put the Mule back together.

Items you will need

  • Wrench set

  • Socket set

  • Screwdriver set

  • Kawasaki pulley tool

  • Straight edge or ruler/yardstick

 How to change a belt on a 50cc 139qmb Chinese Scooter Easily

First you will need to take off the CVT cover from the engine. This cover is held in by several bolts as seen in the picture

When you have pulled the case cover off, There will more than likely be a shredded belt as well as black debris and dust that must be cleaned out thoroughly before a new belt can be installed. Double check both the variator pulley and rear clutch pulley are free from the worn belt.

The next step is to remove the outside half of the variator pulley (fan pulley on the crankshaft) by way of a 17 mm nut. This is the most difficult part of the process because you must keep the engine from rotating to get the nut off. One of the ways of doing this is to wedge a big enough screw driver or block of wood between the engine case and the pulley to keep it from slipping. If you do not feel comfortable doing this method, there are specialty tools available to do this without fear of damaging your scooter. Check out the link at then bottom of this article.

After the nut has been removed, pull off the variator assembly, being careful to note the reinstall arraignment. Inspect the rollers inside, If they have large flat spots and or are broken, replace these as well. After you have inspected these parts, reinstall the variator less the fan pulley half.

Now you need to check the rear clutch pulley for smooth operation. Take both of your hands and grasp the pulley as seen in the picture. Make sure that pulley can move freely when compressing with your fingers.

Compress the rear pulley apart again ,installing the belt on this pulley first. Allow your self enough slack to loop the scooter belt back on to the crankshaft where the other half of the variator fan pulley half will be reinstalled after.

When you have reinstalled the pulley half on the crankshaft, double check that the 17mm retaining nut is on tight to ensure the variator will not come loose while driving your scooter.

When buying a new belt for your 50cc 139QMB based Chinese Scooter, Keep in mind that your riding habits affect the life of the belt. Typically belts can last from 2000 to 8000 miles with normal usage. Kevlar belts are available as a heavy duty option for those that have modified scooters and or for people who tend to be rougher with their driving style.

Items you will need

  • Metric socket set

  • large flat head screwdriver

  • Replacement belt

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