Heres a little information about suspensions.... by CRF916 » Tue Apr 21, 2009 12:25 pm
Heres a little information I found about suspensions. It might help to better understand what your bike is saying to you without saying it.
Suspension Setup Tips
TROUBLE SHOOTING
Various tracks or trail systems may require slightly different settings. Changes made in settings
should be done 1-2 clicks (LS Comp. / Rebound) or 1/4 - 1/2 turn at a time (HS Comp.).
COMPRESSION:
Compression damping controls how soft / hard the fork or shock is when compressed. Some
machines have only a Low Speed Compression adjuster on the shock. The Low Speed
Compression damping is adjusted by clicks. Other shocks today also have a High Speed
Compression adjuster in which the damping is adjusted by turns. Low Speed&High Speed
Compression are terms that relate to how fast the fork or shock is being compressed. High Shaft
Speed creates more damping and is not necessarily relative to motorcycle speed. High Shaft
Speeds can be created at low motorcycle speed. Examples of High Shaft Speed obstacles:
square edged bumps, slap down landings, lipped out jump faces, logs. Examples of Low Shaft
Speed obstacles: rolling bumps / whoops, steep jump faces.
REBOUND
Rebound damping controls how quickly the fork or shock comes back up after being compressed.
The Rebound damping is usually adjusted by clicks.
BOTTOMING:
Is caused by lack of compression damping or too soft of a spring rate. Correct by adjusting the
compression damping stiffer until bottoming is under control. If you run out of adjustment and
bottoming still exists consistently, a stiffer spring rate may be necessary. If spring rate is correct,
too much compression damping is added and harshness is felt in forks then oil level can be
raised to increase bottoming resistance. (Generally 10cc / 10mm (consult your shop manual for
oil level ranges).
SHOCK - Is caused by lack of compression damping or too soft of a spring rate. Correct by
adjusting the compression damping stiffer until bottoming is under control. Note: If the
components have a lot of time on them, bottoming or a soft, springy feeling can be an indication
that a service or rebuild is necessary.
HEADSHAKE / HARSHNESS:
FORK - Is generally caused by too much compression damping in the forks. Soften compression
1-2 clicks. Lighter riders for the size bike you are riding may find it necessary to change to softer
fork springs. Too much rebound damping can also cause a "packing" situation in which the
damping holds the forks down in a stiffer area of the travel than is needed. Soften rebound
damping 1-2 clicks. Other causes can be:
a) Improper fork installation or binding of the fork.
b) Improper shock set up which causes the fork to ride too far into the stroke.
Too much air pressure in your front tire will cause some deflection and harshness feel to
your forks. We recommend only 11-13 psi of pressure.
BACK END KICKS SIDE TO SIDE:
SHOCK - Generally caused by too much compression damping on most types of terrain. Too
much compression damping on square edge terrain can cause the back end to kick side to side
and/or lose traction. Also, too much rebound damping will cause this because the back end is
held down in a stiffer area of the travel which in turn makes it too stiff for the bumps it's hitting
(packing).
BACK END KICKS STRAIGHT UP:
SHOCK - Generally caused by too little or not enough rebound damping. Slow rebound damping
1-2 clicks. Note: In some applications rebound affects compression damping. Adding too much
rebound stiffens the shock damping, decreasing rebound too much softens the shock damping.
VARIOUS TRACKS:
HARD TERRAIN / BLUE GROOVE TERRAIN
Generally adjust compression as soft as possible to handle square edges while still having some
control with bottoming.
INTERMEDIATE / LOAMY TERRAIN
Generally adjust a little stiffer for the softer terrain, jump faces and bottoming. Optimum settings
still should be on the softer side for square edges and rutted corners.
SOFT / SANDY TERRAIN
Generally, stiffen compression and rebound. You want the bike to ride on top of the terrain,
allowing the forks to ride up a little higher.
ROCKY / ROOTY TERRAIN
Generally you need compression very soft to absorb the sharp hits. Rebound is generally
softened to provide a very responsive feel and ride.
0'6 CRF450XXX
