There are a series of adjustments that should be made to see if your Moto-Cross Bike is set up for you.

After a pre-ride inspection and then again after the initial break-in. First among these is the rear suspension race sag adjustments most important.

Setting your shock spring pre-load or race sag according to the guidelines will you have the correct adjustments and spring selection.

A. The first step in determining the proper suspension adjustment is to set the rear spring pre-load to the proper ride height or race sag measurement is achieved.

B. First measure the upload dimension (Bike up on work stand) Point A to point B.

C. Now measure the loaded dimension with the rider on the bike. Point A. to B. Steady the bike upright, put both feet on the pegs. Now bounce on the seat a couple of times to overcome any stickiness.

The Race Sag is the difference between the unloaded and loaded measurements. (24" - 20" = 4" of Race Sag.)

Standard race sag for most 125, 250, or 500 motocrossers is 100mm (3.9")

D. Adjust spring pre-load as necessary to obtain the correct handling results. A race sag setting of 90mm (3.5") improves turing for tight tracts.

Setting the sag to 110mm (4.3") improves stability on faster tracts with less turns, but reduces turning.

E. Determining if you have the right spring. Next you need to compare the rear suspension sag under the weight of the motorcycle only. With no rider, and no stand. Measure point A. to point B. (This is called static sag.)

Static sag is the difference between unloaded and weight of motorcycle only (24" -23.25" = static sag)

After setting the pre-load to obtain the proper race sag of (3.9") the suspension should have .5" to 1.0" of static sag.

Here is the perfect example with the rider on the motorcycle under loaded position he has 4" of race sag and has .75" of static sag with no rider on the motorcycle. The spring has not been over tightened or under tightened to achieve 3.9" of race sag and .75" of Static sag.

F. After setting the spring pre-load to obtain the proper Race sag and the motorcycle sags more than 1" the spring is to stiff for your weight. (you have backed the spring off to far to get the Race sag) Now if your Static sag is less than 4", the spring is to soft for your weight, this requires to much per-load to achieve the proper Race sag and makes the rear top out when the rider dismounts. (Your too much into the spring to get the correct Static sag.)

Suspension Balance

Balancing the front to rear suspension properly is the MOST CRITICAL adjustment for suspension performance. If the front forks are adjusted harder than the suspension, such as changing to a heavier front fork oil ,stiffer compression and rebound setting, air pressure build-up in the front forks etc. the front forks will collapses less on bumps. This transfers more of the motorcycle and rider weight to possibly bottom,where as it felt fine before the front fork adjustment was made.

Balance Test:

Stand next to your motorcycle on level ground and place one foot on the foot peg closest to you. Now push down sharply. The front and rear suspensions should both collapses equally together.

Balancing Tips:

Always check for air pressure build-up in the front forks. Heat and altitude will increase air pressure in your front forks.

Always stay within sag measurement limits of (3.5" to.3" when using spring per-set to stiffen or soften your rear suspension. If this is not possible the next stiffer or softer accessory spring is needed.

The rear shock compression damping can be used to fine tune your suspension balance and is easy to access.

 

After you ride or in between motos, take a clean towel and thoroughly clean the chrome exterior of the fork leg. If you don't, the first time the fork is compressed, the dried dirt particles will be swept into the seal. This is the beginning of a seal leak. If you take the time to wipe the legs of the fork tubes down, it will double your fork seal life!

When washing your bike, take care not to point the pressure washer hose at the seals or fork leg chrome tubes. The high pressure can push the dirt in the wipers right into the fork seal. Again, when you are done washing your bike, take a clean towel and wipe the chrome legs down. The water spots contain dirt and mineral residue. The mineral residue is very sharp when dry and can easily ruin a new pair of wipers and the fork seals.

Other Tidbits

Tying your bike down in the truck does not cause seal problems. The pressure inside a fork actually increases its tendency to seal. If your seals leak when tied down, the damage has already been done and the extra pressure is just helping push the oil out.