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Troubleshooting forks

Troubleshooting forks - Step 1

Symptom Cause Solution
Forks have correct sag, but stop working over a series of bumps Stacking up – forks haven’t had time to re-extend between two obstacles Reduce rebound damping
Knocking from the front end of bike Bushes worn (check also headset adjustments and calliper bolts) Replace bushings – send to service centre
Forks spring back with a jolt after an impact Insufficient damping Increase rebound damping
Forks suddenly start recoil too quickly, even though the adjustment is unchanged Damping mechanism damaged Replace damping mechanism – send to service centre
Forks rebound slowly, even with minimum rebound damping Insufficient lubrication Replace or replenish lubricating oil
  Oil weight too high Use lower weight oil – try 5wt less than current
Forks leak oil from top of fork legs Seals worn or damaged Replace seals – send to service centre
Forks leak oil from lower-leg fixing bolts Fixing bolts working loose Check tightness of fixing bolts
  O-rings on fixing bolts torn or missing Replace O-rings
Air shock bottoms out repeatedly Not enough preload Increase air pressure or spring weight

Troubleshooting forks - Step 2

 

Source : BIKE MAINTENANCE TIPS, TRICKS & TECHNIQUES
See also bike maintenance tips, tricks and techniques “Fitting new reducers and bushings”