How to replace the chain drive.

When you find you have a worn sprocket or chain, you need to replace both sprockets and the chain as a set. Here is the basic concept of how to replace a chain drive set.

1

Many counter sprockets are held with a retaining nut or bolt, some by a snap ring. Remove the retaining nut first. Doing so allows you to use the chain drive, brake and transmission to help hold it from turning. Use first gear. You can also get a helper to hold the brake.

2

Rotate the rear wheel to position the master link on the sprocket as shown and put the transmission in low gear.

3

I remove the clip by using a square end screw driver to twist open the clip while pushing away from the open end. The screw driver should have a width just big enough to open the clip. A tip with rounded corners will be problematic.

4

Now you can push out the link and turn the wheel to feed the chain off of the motorcycle.

5

Sprocket bolts on most modern dirt bikes will be like these, so here are the tools I recommend. You can break torque on the screws while the wheel is mounted, but I prefer to remove the wheel first and do the work on a bench.

6

Use a box end wrench on the nut side to break torque. Only use the hex key to aid in holding the screws. Hex sockets in screws like these can strip out easily.

7

After the torque is broken on all of the screws, you can turn the screw head side to remove them. This is where a ball end hex key comes in handy.

8

Take time to clean the hub ring. I like to use WD-40 and a green Scotch Brite pad. Inspect for damage on the hub. Do not mount a sprocket onto the hub if there are any gouges that cause high spots. The mating surface must be flat and clean.

9

Clean and inspect the sprocket screws. Brush the threads clean if reusing them. Self locking nuts don't need Loctite when new, but some lose their locking performance when reused, so I use medium strength Loctite. If the hardware is getting shabby, replace it.

10

Mount the rear sprocket and lightly tighten the screws. After all screws are lighlty tightened, torque them in a criss-cross pattern.

11

Do a final cleaning on the bike where you will be working. Inspect parts for damage. Make sure axle holes, mating surfaces, counter shaft and chain adjusters are clean and in good condition. Turn the adjusters inward a couple of turns to allow enough slack for mounting the new chain.

12

The counter sprocket still has to come off. It should just slide off. Residual chain lube and dirt may still be present if it is hard to remove. WD-40 can be helpful. Pay attention to the direction of the counter sprocket and watch for the possibility of a spacer sleeve.

13

Chances are this area goes uncleaned most of the time. Clean carefully around the shaft seal area. You don't want to damage the sealing lip of the seal. You also want to avoid pushing material under the seal.

14

Clean all of the wheel hardware and make sure everything is in good condition. Verify your new chain is the right length by counting links.

15

Mount the wheel. I prefer to put a very thin coat of a good multi-purpose grease on the axle before install. This makes disassembly easier next time. Tighten the axle nut to the point the wheel will move move freely back and forth, yet is not too sloppy in the swing arm.

16

Lay the chain out behind the bike and pull it across the sprocket, feeding it onto the counter sprocket.

17

Feed the chain around the counter sprocket and back to the rear.

18

Link the chain together with the ends on the rear sprocket. You can use the sprocket teeth to help hold the chain ends together. Insert the master link from the back side.

19

Position the clip on the link as shown. Make certain the open end of the clip is at the trailing end of normal chain travel.

20

Put the transmission in first gear. This holds the wheel while you pop the clip on. I use the side of a screw driver on the clip edge and give it a tap. Wearing safety glasses is actually a good idea in case you slip up and make the clip fly off.

21

After the clip pops on, look at it closely to make sure it is seated in the grooves on the master link. Also make sure the clip has sprung closed tightly. If the clip has a sloppy fit, it is no good.

22

Install the counter sprocket retainer (a nut in this application). If a nut or bolt is used, I advise applying blue Loctite. Torque to specs for your machine. If a snap ring is used, make sure it is not worn out. Replace it if needed.

23

Check the position of the adjusters on both sides. Make certain they are the same as a starting reference. Now adjust the chain slack appropriately and torque the rear axle nut to spec. Finally, lock the adjusters. SEE CHAIN MAINTENANCE 9.

24

All done. Remember to pump the brake pads tight against the disk before riding.

PARTS AND SUPPLIES

Need parts and supplies for your dirt bike? We have you covered with all the parts and accessories you need from aftermarket to OEM.

CHAIN LUBES

SHOP NOW

DRIVE CHAINS

SHOP NOW

CHAIN GUIDES

SHOP NOW

CHAIN SLIDERS

SHOP NOW

SPROCKETS and KITS

SHOP NOW

CHAIN ROLLERS

SHOP NOW

CHAIN TOOLS

SHOP NOW

OEM PARTS

SHOP NOW