Dirt bike suspension mechanical problems guide

The following is a list of basic dirt bike suspension symptoms. Expand an item to see possible mechanical problems related to each of the symptoms.

Forks
  • Forks bent, dented or deformed
  • Forks clamp(s) bolts overtightened
  • Forks bushing(s) scored and/or siezing
  • Forks out of parallel
  • Excessive oil level
  • Oil too viscous
  • Compression valving stuck closed
  • Compression valving clogged
Shock
  • Shock body dented or deformed
  • Shock internal bushing(s) scored and/or siezing
  • Bent rear shock rod
  • Rear linkage and or shock bearing(s) seizure
  • Swingarm bearing(s) seizure
  • Compression valving stuck closed
  • Compression valving clogged
  • Excessive oil level (improper accumulator setup)
  • Oil too viscous
Forks
  • Loss of pressure due to damaged air cartridge (air forks)
  • Broken spring (spring forks)
  • Insufficient oil level (oil leaking?)
  • Low oil viscosity
  • Compression valving stuck open
  • Compression valving damaged
  • Failed compression valving seal(s)
  • Failed damper piston seal(s)
  • Excessive wear in damping cartridge
Shock
  • Failed accumulator
  • Broken spring
  • Insufficient oil level (oil leaking?)
  • Low oil viscosity
  • Compression valving stuck open
  • Compression valving damaged
  • Failed piston seal
Forks
  • Loss of pressure due to damaged air cartridge (air forks)
  • Broken spring (spring forks)
  • Forks bent, dented or deformed
  • Forks clamp(s) bolts overtightened
  • Forks bushing(s) scored and/or siezing
  • Forks out of parallel
  • Oil too viscous
  • Rebound valving stuck closed
  • Rebound valving clogged
Shock
  • Broken spring
  • Shock body dented or deformed
  • Shock internal bushing(s) scored and/or siezing
  • Bent rear shock rod
  • Rear linkage and or shock bearing(s) seizure
  • Swingarm bearing(s) seizure
  • Rebound valving stuck closed
  • Rebound valving clogged
  • Oil too viscous
Forks
  • Too much air pressure (air or spring forks)
  • Insufficient oil level (oil leaking?)
  • Low oil viscosity
  • Rebound valving stuck open
  • Rebound valving damaged
  • Failed damper piston seal(s)
  • Excessive wear in damping cartridge
Shock
  • Insufficient oil level (oil leaking?)
  • Low oil viscosity
  • Rebound valving stuck open
  • Rebound valving damaged
  • Failed piston seal
Forks
  • Broken spring (spring forks)
  • Forks bent, dented or deformed
  • Forks clamp(s) bolts overtightened
  • Forks bushing(s) scored and/or siezing
  • Forks out of parallel
  • Excessive oil level
  • Other mechanical damage
Shock
  • Broken spring
  • Shock body dented or deformed
  • Shock internal bushing(s) scored and/or siezing
  • Bent rear shock rod
  • Rear linkage and or shock bearing(s) seizure
  • Swingarm bearing(s) seizure
  • Excessive oil level (improper accumulator setup)
  • Other mechanical damage
Forks
  • Broken spring (spring forks)
  • Forks clamp(s) loose
  • Forks bushing(s) badly worn
  • Loose steering head
  • Failed steering head bearings
  • Insufficient oil level
  • Loose front wheel mount
  • Failed front wheel bearings
  • Loose brake caliper
  • Other mechanical damage
Shock
  • Broken spring
  • Shock mount(s) damaged or loose
  • Rear linkage and or shock bearing(s) failure
  • Swingarm bearing(s) failure
  • Insufficient oil level
  • Loose or damaged rear wheel mount
  • Failed rear wheel bearings
  • Other mechanical damage
Forks
  • Dirt packed under fork seals
  • Forks bent, dented or deformed
  • Forks clamp(s) bolts overtightened
  • Forks bushing(s) scored and/or siezing
  • Worn bushings
  • Forks out of parallel
  • Insufficient oil level
  • Other mechanical damage
Shock
  • Dirt packed in linkages
  • Shock body dented or deformed
  • Shock internal bushing(s) scored and/or siezing
  • Bent rear shock rod
  • Rear linkage and or shock bearing(s) seizure
  • Swingarm bearing(s) seizure
  • Insufficient oil level
  • Other mechanical damage
Other advice:

Certainly there can be any number of possible failures in a suspension and good troubleshooting requires knowledge but also an open mind. Modern suspensions are typically made very well, at least on quality machines such as those made by the big motocross bike manufacturers. No matter the possibilities, the likelyhood of having certain problems over others is generally typical. There are times when a suspension exhibits problems simply because it is not set up correctly. Other times, a failure to use good practices in repair and maintenance can result in mechanical failures. No matter the posibilities, mechanical problems will likely be one of the following:

  • Oil needs replaced
  • Worn shock shaft seal causing loss of oil
  • Worn fork tube seals causing loss of oil
  • Impingement of dirt into the fork seals
  • Worn or damaged fork slider bushings
  • Worn piston seals in damping units
  • Pitted, dented or scratched fork tubes causing loss of oil
  • Pitted or scratched shock shaft causing loss of oil
  • Failed steering head bearings
  • Bent rear shock rod
  • Failing rear linkage bearings and/or pins
  • Worn linkage pivot mounts on swingarm or frame
  • Broken spring(s)
  • Failed shock accumulator (bladder or piston style)

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.

FRONT SUSPENSION TUNING

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FORK BUSHINGS

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FORK SEALS

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REAR LINKAGE BEARINGS AND SEALS

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REAR SHOCK REPAIR PARTS

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SPRINGS

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