1997-2001 Honda CR250 – Sprocket & Drive Chain Maintenance

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1997 - 2001 Honda CR250 -Sprocket & Chain Service

How To Service The Sprockets & Drive Chain On Your 97-01 Honda CR250

1997 - 2001 Honda CR250 -Sprocket & Chain ServiceTry always to change your sprockets and chain as a set. Using new parts with old parts will shorten their service life!

The Tools You Will Need

The only specialty tool you will need is a chain breaker. Your master link pins may not be a press fit, but they probably are, and you will need the right tool.

New Chain And Sprocket Parts

You will need a new O-ring, part number 91201-ML3-873, for the countershaft and possibly a new set of sprockets and a chain, but you’ll find that out later.

Pre-Service Notes

  • Start with your bike on a stand and your transmission in 1st gear.
  • I recommend opening the Service & Torque Specs in a new tab for easy reference.
  • If you need parts and tools, make sure to buy them here!
  • Pictures with captions are after the steps below.
  • If you need any help, don’t hesitate to ask!

Sprocket & Drive Chain Removal

Front/Drive Sprocket Removal

    1. Remove the front sprocket guard and backing plate.
    2. If you try to turn the bolt, you will turn the engine, so use a ratchet strap to hold down the rear brake.
    3. With the rear brake engaged, loosen and remove the front sprocket bolt, washer, and sprocket from the countershaft.
    4. With the rear brake engaged, loosen and remove the front sprocket bolt, washer, and sprocket from the countershaft.
    5. Carefully remove the collar from the countershaft.
    6. Be careful around the countershaft seal; if you use a screwdriver to pry the collar out, be patient!
Remove the front sprocket guard and backing plate.
Remove the front sprocket guard and backing plate.
If you try to turn the bolt, you will turn the engine, so use a ratchet strap to hold down the rear brake.
If you try to turn the bolt, you will turn the engine, so use a ratchet strap to hold down the rear brake.
With the rear brake engaged, loosen and remove the front sprocket bolt, washer, and sprocket from the countershaft.
With the rear brake engaged, loosen and remove the front sprocket bolt, washer, and sprocket from the countershaft.
Carefully remove the collar from the countershaft.
Carefully remove the collar from the countershaft.

Rear/Driven Sprocket Removal

  1. Lay your rear wheel on a towel with the brake side down.
  2. Coat the sprocket bolts with PB blaster, then flip your wheel and spray the sprocket nuts.
  3. After the PB does its job, loosen and remove the rear sprocket hardware.
Lay your rear wheel on a towel with the brake side down.
Lay your rear wheel on a towel with the brake side down.
Coat the sprocket bolts with PB blaster, then flip your wheel and spray the sprocket nuts.
Coat the sprocket bolts with PB blaster, then flip your wheel and spray the sprocket nuts.
Spray Rear Sprocket Nuts With PB Blaster
Spray Rear Sprocket Nuts With PB Blaster
After the PB does its job, loosen and remove the rear sprocket hardware.
After the PB does its job, loosen and remove the rear sprocket hardware.

Related: How to service the rear master cylinder on your 97-01 CR250.

Chain Removal

  1. Locate the master link, then rotate the chain to sit on the swing arm.
  2. Lay your left forearm on the chain, with your screwdriver facing the front of the bike.
  3. Align the blade of your screwdriver with the open end of the spring clip.
    • If installed correctly, the open end should face your bike’s back.
  4. Give the butt of the screwdriver a tap with your rubber mallet, and the spring should pop off the pins.
  5. Align your chain breaker so it pushes the pins toward the bike, and remove the pins.
Locate the master link, then rotate the chain, so it sits on top of the swingarm.
Locate the master link, then rotate the chain to sit on top of the swing arm.
Lay your left forearm on the chain, with your screwdriver facing the front of the bike.
Lay your left forearm on the chain, with your screwdriver facing the front of the bike.
Align the blade of your screwdriver with the open end of the spring clip.
Align the blade of your screwdriver with the open end of the spring clip.
Give the butt of the screwdriver a tap with your rubber mallet and the spring should pop off the pins.
Give the butt of the screwdriver a tap with your rubber mallet, and the spring should pop off the pins.
Align your chain breaker, so it pushes the pins toward the bike, and remove the pins
Align your chain breaker so it pushes the pins toward the bike, and remove the pins.

Sprocket & Drive Chain Inspection

  1. Before you bother cleaning the sprockets and chain, check to see if they are worth keeping.
  2. Check both sprockets for excessive tooth wear.
  3. Check the back sprocket for signs of uneven wear and straightness.
  4. There is a wear spot on the rear sprocket, but it’s most likely something I hit because it is still straight and worn evenly.
Before you bother cleaning the sprockets and chain, check to see if they are worth keeping.
Before you bother cleaning the sprockets and chain, check to see if they are worth keeping.
Check both sprockets for excessive tooth wear.
Check both sprockets for excessive tooth wear.
Check the back sprocket for signs of uneven wear and straightness.
Check the back sprocket for signs of uneven wear and straightness.
There is a wear spot on the rear sprocket, but it’s most likely something I hit because the sprocket is still straight and worn evenly.
There is a wear spot on the rear sprocket, but it’s most likely something I hit because it is still straight and worn evenly.

Chain Inspection

  1. Lay your chain flat, pull it straight, and measure the span of 17 pins.
  2. The span between the 1st and 17th pin should not exceed 10 and 1/8th inch.
  3. Check the pins and side plates for damage or signs of uneven wear.
    • This chain and sprocket set are still good, so I saved myself about $100 today!
Lay your chain flat and pull it straight and measure the span of 17 pins.
Lay your chain flat, pull it straight, and measure the span of 17 pins.
Check the pins and side plates for damage or signs of uneven wear.
Check the pins and side plates for damage or signs of uneven wear.

Clean & Inspect

  1. Clean everything with carburetor cleaner, then rinse with warm water.
  2. Hang your chain, and wrap everything else in a towel to dry.
  3. Clean your countershaft using a carb cleaner, a towel, and a tiny screwdriver.
  4. Clean the splines as best as you can.
  5. Once the countershaft is thoroughly wiped down, remove the O-ring and throw it away.
Clean everything with carburetor cleaner, then rinse with warm water.
Clean everything with carburetor cleaner, then rinse with warm water.
Hang your chain, and wrap everything else in a towel to dry.
Hang your chain, and wrap everything else in a towel to dry.
Clean your countershaft using carb cleaner, a towel, and a tiny screwdriver.
Clean your countershaft using a carb cleaner, a towel, and a tiny screwdriver.
Once the countershaft is thoroughly wiped down, remove the O-ring, and throw it away.
Once the countershaft is thoroughly wiped down, remove the O-ring and throw it away.

Sprocket & Drive Chain Installation

Rear/Driven Sprocket Installation

  1. Start your installation with the rear sprocket.
  2. Install the sprocket hardware hand-tight, then torque the rear sprocket bolts in a criss-cross pattern.
    • Torque to 24 ft lbs
Start your installation with the rear sprocket.
Start your installation with the rear sprocket.
Install the sprocket hardware hand tight, then torque the rear sprocket bolts in a criss-cross pattern. Torque to 24 ft-lbs
Install the sprocket hardware hand-tight, then torque the rear sprocket bolts in a criss-cross pattern. Torque to 24 ft lbs

Front/Drive Sprocket Installation

  1. Install the new o-ring onto the countershaft.
  2. Grease and install the collar with the groove facing in.
  3. Mount the front sprocket with the flat side facing out.
  4. Install the bolt and washer with the outside markings facing out.
New O-Ring For Countershaft Part Number 91201-ML3-873
New O-Ring For Countershaft Part Number 91201-ML3-873
Install the new o-ring onto the countershaft.
Install the new o-ring onto the countershaft.
Grease and install the collar with the groove facing in.
Grease and install the collar with the groove facing in.
Mount the front sprocket with the flat side facing out.
Mount the front sprocket with the flat side facing out.
Install the bolt and washer with the outside markings facing out.
Install the bolt and washer with the outside markings facing out.

Related: How to bleed your 1997-01 Honda CR250 brakes.

Chain Installation

  1. Run your chain through the guides so the ends meet on the swingarm.
    • The easiest way I have found to install an O-ring master link is to drive the pins through the inside plate first.
  2. Place the o-rings on the pins, then slide the pins through the holes.
  3. Then, take the inside of the chain breaker and press the outside plate onto the pins.
    • Once the pins are pressed in, install the spring clip.
  4. Align the spring clip with the closed end facing forward.
  5. With your screwdriver, pry the open end halfway onto the link.
  6. Then, push the clip the rest of the way.
  7. Install your chain on both sprockets.
  8. Apply the rear brake and torque the sprocket bolt.
    • Torque to 20 ft lbs
  9. Reinstall the sprocket guard and bracket.
Run your chain through the guides, so the ends meet on top of the swingarm.
Run your chain through the guides so the ends meet on the swingarm.
Place the o-rings on the pins, then slide the pins through the holes.
Place the o-rings on the pins, then slide the pins through the holes.
Then take the inside of the chain breaker to press the outside plate onto the pins.
Then, take the inside of the chain breaker and press the outside plate onto the pins.
Align the spring clip, with the closed end facing forward.
Align the spring clip with the closed end facing forward.
With your screwdriver, pry the open end halfway onto the link.
With your screwdriver, pry the open end halfway onto the link.
Then push the clip the rest of the way.
Then, push the clip the rest of the way.
Install your chain on both sprockets.
Install your chain on both sprockets.
Apply the rear brake, and torque the sprocket bolt. Torque to 20 ft-lbs
Apply the rear brake and torque the sprocket bolt. Torque to 20 ft lbs

If you have any questions or anything to add, please leave them in the comments or on our Facebook page!

Keep Your ’97-’01 CR250 Running Right!

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