Adjusting your motorcycle's chain tension is a critical maintenance task that ensures safe riding, extends the life of your chain and sprockets, and optimizes power transfer. The process primarily involves manipulating adjusters on both sides of the rear axle to achieve the correct amount of chain slack.
Why Proper Chain Tension is Crucial
Maintaining the correct chain tension is paramount for several reasons:
- Safety: An overly loose chain can derail, potentially locking the rear wheel, while an overly tight chain can put excessive stress on engine and transmission components, leading to premature wear or even damage.
- Component Lifespan: Correct tension prevents abnormal wear on the chain, sprockets, and wheel bearings.
- Performance: Proper tension ensures efficient power delivery from the engine to the rear wheel.
Tools You'll Need
Before you begin, gather these common tools:
- Metric Wrenches or Sockets: For the axle nut and chain adjuster lock nuts.
- Measuring Device: A ruler or tape measure to check chain slack.
- Torque Wrench: Essential for re-tightening the axle nut to the manufacturer's specifications.
- Shop Stand or Paddock Stand: To lift the rear wheel off the ground, making it easier to rotate and adjust.
Step-by-Step Chain Adjustment Process
Adjusting your motorcycle chain is a straightforward procedure. Here's how to do it:
1. Prepare Your Motorcycle
- Place your motorcycle on a paddock stand or center stand so that the rear wheel is off the ground and can spin freely.
- Ensure the motorcycle is in neutral.
2. Locate the Adjusters
- Identify the chain adjusters located on both sides of the swingarm, near the rear axle. These typically consist of a threaded bolt or cam mechanism and a locking nut.
- Remember, as the reference states, "There are of course adjusters on both sides of the axle."
3. Measure Current Chain Slack
- Push the chain up and down at its loosest point, usually about midway between the front and rear sprockets.
- Measure the total vertical free play (slack). This measurement should fall within the range specified in your motorcycle's owner's manual (e.g., 20-30mm, but always consult your specific model's manual).
4. Loosen the Axle Nut
- Using the appropriate wrench or socket, loosen the large axle nut on one side of the rear wheel. You don't need to remove it, just loosen it enough to allow the axle to slide. This is implied by the reference's instruction to "Free then turn the adjuster."
5. Adjust Chain Tension
- Loosen the lock nuts on both chain adjusters.
- Now, turn the adjuster bolts/cams. To increase tension (reduce slack), turn the adjusters clockwise, pushing the axle backward. To decrease tension (increase slack), turn them counter-clockwise, allowing the axle to move forward.
- Crucially, turn the adjusters "a quarter turn at a time" on both sides of the axle, as highlighted in the reference. This allows for precise adjustments to "shift the axle position and change the chain slack."
- Make small, symmetrical adjustments on both sides to keep the wheel aligned. After each small adjustment, gently push the wheel forward or backward to ensure the axle settles.
- Periodically re-measure the chain slack to ensure you're approaching the correct specification.
6. Re-tighten the Axle Nut
- Once the chain slack is within the manufacturer's recommended range, re-tighten the axle nut to the torque specification found in your owner's manual. This is a critical step to prevent the axle from shifting and ensure wheel security.
- Tighten the adjuster lock nuts as well.
7. Re-check Slack and Alignment
- After tightening everything, re-check the chain slack at multiple points along the chain (by rotating the wheel) to account for any tight spots. The slack should be consistent.
- Verify wheel alignment. Most swingarms have alignment marks near the adjusters. Ensure the marks on both sides indicate the same position. Misalignment can lead to uneven tire wear and poor handling.
Understanding Chain Slack Specifications
The ideal chain slack varies by motorcycle model. Refer to your owner's manual for the exact specification for your bike. A general guideline for sportbikes might be 20-30mm, while adventure bikes with longer suspension travel might require more slack, sometimes up to 40-50mm.
| Type of Motorcycle | Typical Chain Slack Range (Approximate) |
|---|---|
| Sportbike | 20-30 mm (0.8-1.2 inches) |
| Standard/Cruiser | 25-35 mm (1.0-1.4 inches) |
| Adventure/Off-Road | 35-50 mm (1.4-2.0 inches) |
Note: Always consult your motorcycle's specific owner's manual for the precise measurement.
Common Mistakes to Avoid
- Overtightening the Chain: This is a common mistake and can lead to severe damage to the engine's output shaft bearing, countershaft sprocket, and even the chain itself.
- Uneven Adjustment: Not adjusting both sides equally will cause wheel misalignment, leading to poor handling and premature tire wear.
- Ignoring Torque Specs: Failing to torque the axle nut correctly can result in the wheel coming loose or damage to the axle threads.
Final Maintenance Tips
After adjusting the chain, it's also a good time to:
- Clean and Lubricate: Use a dedicated chain cleaner to remove old grease and grime, then apply a high-quality chain lubricant. This significantly extends chain life.
- Inspect for Wear: Check for kinked links, rust, or excessive wear on the chain and sprockets. Replace components if necessary.
By following these steps and paying attention to detail, you can effectively adjust your motorcycle's chain tension, ensuring a safer and more enjoyable ride.
