Suspension Tuning

Ride Height

Meauserment A: With  bike on a stand  and the rear wheel unweighted, measure from a point on the rea

Meauserment A: With  bike on a stand  and the rear wheel unweighted, measure from a point on the rear fender to the centre of the axle (try to keep it at a 90 degree angle from the ground).

Record this measurement.  Example: 620 m.m.

Measurement B: With gear on and motorcycle off the stand sit in a neutral position on the bike, usually your butt inline with the foot pegs.

Now record this  measurement. Example: 515 m.m.

Now subtract measurement B from measurement A, this will give you your race sag. Example: 620-515=105 mm of race sag.

Measurement C: This  is your free sag measurement, with no rider and bike of the stand push up and down a few times on the rear of bike. Take measurement front same point on fender as in A to the rear axle again, record this measurement. This will give you your free sag.Example: 620 mm. - 600 mm = 20 mm of free sag. 

Preferred free sag is 20-40 mm depending on riding style and motorcycle. Refer to manual or Marshall’s Racing pamphlet for desired sag.

Proper Race Sag

  • Recommended Race Sags

65 cc machines: 65-75 mm

85-105 cc machines: 80-90 mm

125-500 cc machines: 100-115 mm

Remember these are only recommended race sags, always refer to owners manual or Marshall’s racing pamphlet for preferred race sag.

To increase race sag (lower rear of bike) turn spring counter clockwise.

To decrease sag (raise rear of bike) turn spring clockwise.

With desired race sag your free sag should be between 20-40 mm. 

Less than 20 mm free sag requires a stiffer rear shock spring. More than 40 mm requires a lighter rear shock spring.

Proper Installation

Proper installation of your suspension components can drastically affect the handling of your motorcycle, when installing the forks always be sure the tubes are clean of all oils and grease. Set the fork tubes to the recommended height per your pamphlet and always torque the triple clamp bolts to specified  spec.( usually between 14-16 foot lbs.) Install the wheel and tighten brake side fork lug bolts. Now spin the front wheel a few times and touch and hold the front brake, while holding front brake tighten right side fork lugs. All this insures proper fork alignment prevents any binding of the forks.

When installing the rear shock always grease your shock bolts as well as checking all linkage bolts for proper torque and installation. (Always check linkage for proper lubrication and smooth action.) With shock in the chassis preload the rear wheel by lifting up on it. Now tighten all your shock and linkage bolts to specified torque specs. After installation of fork and shock be sure to check your race sag (ride height) as well as free sag.

Remember your race sag is a really important factor in the handling of your machine.

Hope you like your new Suspension

Thank you for choosing Marshall’s for your suspension need,s We take pride in our work and want you the customer to enjoy your own personalized revalved suspension., with our knowledge and experience in the racing field you should enjoy your new set-up. We strive in perfection and customer satisfaction at Marshall’s racing. However if you have any questions concerning your suspension feel free to 

contact us at marshall@marshallsracing.com or phone 405-377-0192.at anytime.

If your having any difficulties with your suspension, our friendly support staff is always willing to assist you with all your racing related questions. 

Suspension Troubleshooting

Different tracks or trails require different settings, we recommend going 2 clicks at a time or ¼ turns when there is no clicked settings. 

Compression: Compression is how soft or hard the fork is when compressed, some components have low and hi speed settings. Low speed is the shaft speed of which the fork or shock is being compressed, this is not necessarily the speed of the motorcycle. Low shaft speed examples are rolling bumps, steep jump faces etc..

Hi  speed compression is the shaft speed on Hi impact hits such as square edge bumps, lipped jump faces, slapping down of the suspension and logs. G outs are usually a hi speed impact as well. 

Rebound: Rebound is the return action of the shock or fork and is usually controlled by clickers unless it is a smaller CC bike. 

A good rule of thumb is you want the compression and rebound action very close to even when you push up and down on your suspension.

Bottoming

Fork: This is usually caused by a lack of compression setting, or to soft of fork spring. Turn in clickers 2 clicks at a time to you get your desired feel. Going in to far on your settings usually will create a harsher feeling, we recommend adding more oil or going to a stiffer spring if you have your adjuster in beyond 4 clicks.

Shock: This is usually caused by a lack of compression or to soft of a shock spring, to stiffen add more compression until bottoming is under control. If this does not fix the problem try going   to a stiffer rear spring. Please note that worn components or oil contamination can lead to a soft feeling shock.

Head shake

Fork head shake is caused by to much compression dampening in the forks, soften forks 2 clicks till you get your desired feel. If the rider is light make sure you have the correct spring rate. Also to much rebound dampening in the fork will hold it down in the stroke causing a harsh feeling. 

Fork height can also lead to head shake, start off at recommended fork height as refereed to in your manual or suspension pamphlet. Raising forks in clamp will add more weight to the front of the bike and should eliminate most of your head shake.

Also make sure forks are not in a bind and are aligned properly, refer to our suspension tuning page for instructions on how to align forks.

Shock

Back end kicking side to side: Usually caused by to stiff of compression or to much rebound which holds suspension down into the harsh part of the stroke. Try going softer 2 clicks at a time on compression or 1 click softer rebound (faster) until problems is corrected.

Back end kicking straight up: Usually caused by not enough rebound dampening, try stiffening the rebound (slower) until desired feel is reached. Also to soft of compression can cause this as well. One thing to remember is the rebound does affect the compression on the shock, adding rebound will stiffen the shock and less rebound will soften the shock..

A good way of telling how balanced your suspension is, by holding on the front brake and pushing up and down on foot pegs. The front and rear suspension should move evenly. If your suspension feels unbalanced please  

adjust accordingly.

VARIOUS TRACK CONDITIONS

A good rule of thumb is as the track gets harder you usually want to soften the suspension being careful not to go to soft, this will create the suspension to bottom. As the track gets softer you can usually go stiffer by 2-4 clicks to you get a comfortable feel.

Sandy Conditions: In sandy conditions you should stiffen the fork compression and add a few clicks of rebound to the shock

, this will allow the suspension to ride on top of the sand. If  it is really rough and sandy raising the front of the bike (lowering the forks in the triple clamp) by 3-5 mm.

Muddy Conditions: Muddy conditions are usually the same as sand but you can exaggerate it a few clicks if the mud is heavy and sticking to the bike. For the serious PRO Racer if the track is really muddy and heavy mud adding weight to your bike, you might consider installing stiffer fork springs and adding a turn or two pre-load into your shock.

Rooty/Rocky Conditions: You should soften the compression to absorb the square edge hits and sharp edges of the roots and or rocks. You can usually go a little softer on the rebound (faster) to make your suspension a little more responsive and smoother.

Marshall’s hope these tips help you in your racing, if you are still having problems feel free to call us or contact us by e-mail at Support@marshallsracing.com .

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