Off Road Suspension

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Off Road Suspension

Postby Shakti Stunter » Fri Jul 29, 2005 1:51 pm

more info can be found on http://www.webbikeworld.com/motorcycle- ... uspension/ and below http://www.mx-tech.com/tuning_offroad.asp

SHOCKS - Setting the rebound:

1.) Find a relatively fast trail with braking bumps, rocks and roots leading into the entrance of a corner. Reduce (Turn clicker out) the rebound damping until the rear end begins to hop or feel loose. Finally, increase (Turn clicker in) the rebound damping until the sensation goes away.

2.) Find a log or ledge that tends to bounce the motorcycle after hitting it. If the rear end bounces up uncontrollably, add rebound. (Turn clicker in)

3.) Find some large whoops. The motorcycle should track straight through the whoops with the rear wheel extending to the ground before the next impact. If it does not perform as described, as above, it is packing and the rebound dampening should be reduced! (Turn clicker out) (Please note the guide for sand set-up, as these rules don't apply for sand.)

4.) Find a corner with acceleration bumps, rocks, and roots on the exit. The rear of the motorcycle should follow the ground. If the rear end "breaks up", reduce the rebound. (Turn clicker out) (If this fails soften the compression two clicks.) (Turn clicker out)

SHOCK: Setting the compression:

1.) Find some rough sections, a large jump and a couple of "G-Outs". The shock should bottom on the roughest section but it should not be a slamming sensation. Add compression to fight bottoming. (Turn clicker in.) But avoid going to far as the suspension's ability to react to small variations of surface and rocks will be sacrificed in the trade. Remember the adjusters have a primary effect on the low speed, so even a large change in setting may only effect bottoming resistance slightly. Remember bottoming your suspension is not necessarily a bad thing. You should strive to bottom off the biggest bottoming load obstacle on the trail. If you don't you're not getting maximum plushness from your suspension. Run your suspension as soft as you can get away with but remember that if the trail has sand sections or lots of g-loads this will work against you.

FORKS: Setting the compression:

1.) The forks should react to all trail variations. If the forks seem harsh on small bumps, holes, rocks, or roots soften the compression. (Turn clicker out) If they are relatively smooth, stiffen (Turn clicker in.) until they do feel harsh and then turn back a click or two.

2.) Now find the rough part of the trail again. The forks should bottom over the worst g-load or jump. If harsh bottoming occurs, add oil in 5-mm increments.

FORKS - Setting the rebound:

The rebound damping is responsible for the stability and the cornering characteristics of the motorcycle.

1) Find a short sweeper. When the forks compress for the turn, the speed at which the forks return is the energy that pushes your front wheel into the ground. If the forks rebound too quickly, the energy will be used up and the bike will drift wide, or wash. If the rebound is too slow, the bike will tuck under and turn too soon to the inside.

2). With the bike turning well, the wheel should return to the ground quickly and not deflect off successive impacts. If it does, reduce the rebound. (Turn out)

Guidelines for different conditions:

For hardpack to intermediate:

Set the compression softer, (Turn clicker out) front and rear to help get maximum wheel contact and plushness.

Sand conditions:

(Non-square edged bumps); More low speed compression and rebound are necessary. Start by adding 1-2 clicks (Turn clicker in.) of rebound and as the track gets rough, add compression 1-4 clicks. (Turn clicker in.) (Supplementary sand set-up techniques). Harshness is a result of packing in forks. Remember to add compression (Turn clicker in) to help keep the front end from packing The rear suspension will exhibit packing by swapping. To eliminate swapping begin adding compression (Turn clicker in) until the bike tracks straight and then add rebound (Turn clicker in) to keep the rear following the terrain of each whoop. Don't be concerned if your clickers are nearly maxed out in sand conditions. Unless of course you had your bike revalved for sand. [/color]

Rocks and Roots:

Rocks and roots will make your suspension work at it’s worst. Try reducing compression till the suspension can react and not deflect off every impact.

Shock Maintenance

* linkage cleaned and greased every 3-6 months / major ride
* seals replaced once a year

Forks

* gas pressure bled once a week
* oil changed once a month
* full service once every 3 months

MX SUSPENSION TROUBLESHOOTING
http://www.motocross.com/motoprof

Rear Shock Troubleshooting

Rear shock bounces over bumps while accelerating, will not hook up. Lack of traction due to a stiff shock.
*Decrease shock spring preload.
*Decrease shock compression damping
*Install softer spring.

Rear shock kicks up during braking.
*Increase rebound damping.
*Increase shock rebound damping.

Rear shock feels soft on large bumps or jumps. Increase shock compression damping.
*Decrease race sag.
*Install stiffer spring.
*Shock made need re-valving.

Rear shock feels too hard over jumps, large bumps, or a series of small bumps.
*Decrease shock compression damping.
*Increase sag.
*Install softer spring.
*Shock may need re-valving

Front Fork Troubleshooting

Front end "knifes" or oversteers in turns (front end will turn inward). This is caused by soft forks.
*Slide the fork tubes down 5mm in the triple clamps.
*Increase compression damping.
*Raise fork oil level.
*Install stiffer springs.

Front forks stiffen up at the end of the stroke.
*Reduce the fork oil level.

Forks overall feel is too stiff.
*Decrease compression damping.
*Lower fork oil level.
*Install softer fork springs.
*Re-valve front forks.

Forks dive excessively during braking.
*Increase compression damping.
*Raise fork oil level.
*Install heavier fork oil.
*Install stiffer springs.
*Re-valve front forks.

Front pushes or washes out in turns. This is caused by stiff forks. *Release built up air in the forks.
*Decrease compression damping.
*Slide forks tubes up 5 mm.
*Lower fork oil level.
*Install softer springs.

Front end searches while going down hill or during acceleration out of corners. The is caused by soft forks.
*Increase compression damping.
*Raise the fork oil height.
*Install heavier springs.
*Increase fork spring preload.
*Re-valve forks.

Front forks do not respond to small bumps in sweeping turns. They may hop over the small bumps. This is caused by stiff forks.
*Decrease compression damping.
*Decrease for oil level.
*Install softer fork springs.
*Re-valve front forks.

Front end shakes under braking.
*Decrease shock sag.
*Increase shock rebound.
*Raise fork oil level.
May a flea climb up my ass find happiness.
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Shakti Stunter
 
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Postby j-rad » Mon Aug 01, 2005 9:34 am

WOW - thanks Kali7. Very informative!

We use a local guy for all our suspension needs. 'SuspensionSmith'.
Laurie Smith - 13 Isa St Fyshwick. 0407 903 652. He is THE man for suspension work. Road or trail.
He worked on my various GSXRs over the years and has always done a top rate job. I've passed all my mates onto him and everyone has been happy.

OR read Kali's msg and have a go yerself!
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