Symptoms
- Chain visibly sags more than usual
- Clunking or slapping noise from the chain area, especially at low speed
- Rough or jerky power delivery
Likely causes
- CommonNormal chain stretch from wearChains gradually stretch with mileage and need periodic tightening as part of routine maintenance.
- CommonChain not adjusted since last tire or chain serviceSlack increases over time and needs to be checked every few hundred to a thousand miles depending on the bike.
- PossibleWorn or stretched beyond safe adjustment rangeA very worn chain may run out of adjustment room and need replacement rather than just tightening.
What to do
- Put the bike on its center stand or a rear stand so the rear wheel can move freely.
- Check your manual for the correct slack measurement (usually 1–1.5 inches of up-down movement at the tightest point of the chain, varies by model).
- Rotate the rear wheel to find the tightest point in the chain's travel and measure slack there.
- If slack is beyond spec, loosen the rear axle nut, then adjust the chain adjusters evenly on both sides to maintain wheel alignment.
- Re-tighten the axle nut to the correct torque and recheck slack and wheel alignment using the markers on the swingarm.
- Lubricate the chain after adjusting if it looks dry, and recheck slack again after a short ride.
Tools and parts
- Wrench set
- Torque wrench
- Ruler or chain slack tool
Chain lubricantSearch: “motorcycle chain lube”
When to call a pro
If the chain is at the end of its adjustment range or shows kinks/tight spots, have it and the sprockets inspected for replacement.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.