Here's some info I found.....
All right ladies, this is what I did last weekend after installing my YFZ450 shocks and should help you out.
Getting The Best Out Of Stock Shocks Suspension is a mysterious subject for many people. As mysterious as it may seem, it's important to understand how it works. Your quad's shocks can single-handedly make the biggest difference in your quad riding experience. It may seem like adding more horsepower or slapping on aggressive tires will alter your ride the most, but if you're riding on anything other than a straight, flat trail, you're going to appreciate having a well-set-up suspension working underneath you.
Having a good suspension doesn't mean you have to go out and spend a bunch of money on new shocks. In fact, there is plenty you can do to improve the ride quality of your quad's current stock shocks. Not all shocks are created equal-some are more adjustable than others. But we at Quad Off-Road think the best option is starting with stock shocks (which is easy on the wallet) and tuning them until you can't make them any better or your riding level has progressed beyond what the stock shocks can handle. Only then should you consider upgrading to something with more adjustability.
Suspension Types There are three basic types of shocks currently available on production quads.
Standard Non-Adjustable Shocks: These shocks are found on smaller, more cost-efficient quads such as youth quads. As the name suggests, they do not have any adjustability and rely heavily on the spring to produce suspension action (to soak up the bumps and jumps).
Pre-load Adjustable Shocks: These shocks are usually found on entry-level sport quads as well as most sport/utility quads. Preload adjustable suspensions have two types: the first generally uses five pre-determined preload settings, while the other uses a threaded lock ring mechanism. Both types work on the same principle to adjust suspension action.
Fully Adjustable Piggyback Reservoir: The most advanced form of stock suspension is the fully adjustable piggyback shock. This type of shock is found on the newest batch of sport quads and features compression, rebound, and threaded preload adjustments that allow a rider to completely customize the suspension ride quality of their machine.
Setting Up Your Suspension: Now that you know the different types of suspension, figure out what kind of setup your quad is equipped with. Got it? Good. Now take some measurements to see how you can best adjust your quad's suspension.
Free Sag: This first measurement determines how much free sag your suspension has. Free sag (also called static sag) is the amount of suspension travel that is used when the quad is under its own weight subtracted from the overall suspension travel. Huh? Don't worry, it sounds more technical and tough than it is.
Determining these measurements for the front and rear suspension require two different methods:
Front Suspension: Have a friend lift the front end of the quad until the A-arms are fully extended but the tires are still in contact with the ground. Take a measurement from the floor to a center point on the front of the quad's frame (mark the point with a marker because you must use that as a point of reference for future measurements). This is called the "unloaded measurement." Once this measurement has been taken, put the unit back on the ground and bounce the front suspension to let it settle in. Now measure from the ground to the same point on the frame. Subtract the weighted measurement (the second measurement) from the unloaded measurement (the first measurement) to obtain your free sag value. Ideally, the number you get after doing the math should be around 10 percent of your quad's total suspension travel (example: 1 inch of sag for 10 inches of total suspension travel).
Rear Suspension: To measure the free sag for the rear end, lift at the grab bar until the suspension is unloaded with the tires still touching the ground and take a measurement from the grab bar to a chosen point on the swingarm. Once this measurement is taken, drop the unit back on the ground and bounce the suspension to let it settle.
Now that your quad is back on the ground and under it's own weight, take a measurement from the same point on the grab bar to the same point on the swing arm. Subtract the loaded suspension value (the second measurement) from the unloaded value (the first measurement); this value should again be as close to 10 percent of the total suspension travel as possible.
NOTE: This method is for quads with a solid rear axle. For a quad with independent rear suspension, follow the instructions for measuring free sag for front suspension. Make sure that each of these measurements have been recorded on a piece of paper and saved for future reference. And double check your measurements and math!
Rider Sag: The second type of suspension measurement that is important to the ride quality of your quad is rider sag. Of the two types of sag, rider sag is the more important type, but having both values within the proper measurements is the best setup. Rider sag is the measure of how much of the total suspension travel is used when a fully geared rider is sitting in a normal riding position. Rider sag should be somewhere around 30 percent of the total suspension travel of your quad (example: 3 inches of sag for 9 inches of total suspension travel).
To measure the front and rear rider sag, suit up in your gear and sit on the machine in your normal riding position (hands on handlebars and neutral body position). Have a friend measure from the rear grab bar to the marked point on the swing arm and record the measurement. For the front measure from the marked point on the frame to the ground, just as you did for free sag, and record your measurement. Now subtract the rider sag value from the unloaded suspension measurements (front and rear) already taken during the free sag measurement. Like we stated earlier, 30 percent is the goal.
What Do These Measurements Mean? Understanding the importance of sag is just as critical as setting it. Accurately setting your quad's rider sag is important because it determines how your quad carries itself and you, which in turn effects how the quad reacts over every bump, hole, and rock. If the quad were to be setup with too little rider sag, it would ride too high in the suspension travel and not allow the suspension to work accurately. Conversely, if there is too much rider sag the suspension will be so soft that it blows through the travel over small bumps and won't react properly to big hits. This will make your rear end and back very unhappy.
The relationship between rider sag and free sag is an important one to understand. When rider sag is set properly and the free sag is off, it means that the spring rate of the shock spring is incorrect for the application. This shouldn't be the case because most quad manufacturers do abundant suspension testing to try and ensure the best possible suspension setup. If your rider sag/free sag relationship is way off, or if it just plain confuses you, don't be afraid to take your quad to a professional and ask for help.
Making Sag Changes: Once all of the measurements have been taken and recorded it is time to make some adjustments. If your quad is sagging too much and you have a five-way preload-adjustable shock, simply take a pair of adjustable pliers or the provided tool that came with your machine and crank the preload up (make the spring length shorter) one click at a time until it measures the proper amount of sag. If your shock is a threaded type, unlock the locking nut with a hammer and punch, then turn the shock clockwise (again making the spring shorter) half a turn at a time until it meets the required measurements. If each sag value is less than the recommended suspension measurement, loosen the collar (make the spring longer) to bring it to the proper value. If for some reason the rider sag and free sag cannot be brought into spec together, make sure the rider sag is set first.
Shock Adjustments: Now that the rider and free sag have been adjusted, it is important to understand the adjustment that each one of the shocks on your quad has. Each quad shock can be different and could have a different combination of the following adjustments, so look at your quad's shocks carefully to see what you have to work with.
Low-Speed Compression: Most shocks have a single compression adjuster that is called a low-speed compression adjuster. The low-speed compression adjuster is speed sensitive, and therefore controls the shock action over obstacles such as g-outs, whoops, and jumps landings. Usually this adjuster is controlled by a screw head (flat head) that clicks as the adjuster is turned in or out. Turning the clicker clockwise makes the compression harder, and turning it counter-clockwise makes the suspension softer. Start tweaking it by turning the adjuster all the way in and then count the clicks out until it stops. At this point, turn the adjuster in again to half the total number of clicks (generally 12-14).
High-Speed Compression: Shocks that have a high-speed compression adjustment are generally adjusted with a 17mm socket and have around two to three turns of adjustment. The high-speed adjustment controls shock action over quick chatter bumps, acceleration bumps, and braking bumps (hence the "high-speed" part of the name). A softer high-speed setting (1.5 to 2.5 turns out) will work better in a highly choppy area, while a harder setting (.5 to 1.5 turns out) will work better on a smooth track or in the dunes.
Rebound: The rebound adjuster controls the speed of the shock action as the spring pushes the shock shaft back out to its original position after it has been compressed. Once a spring has been compressed, it wants to react uncontrollably to come to a normal uncompressed state-rebound damping helps "fight" the spring in order to have a controlled spring return. As with compression, the place to start adjusting rebound is to turn the adjuster all the way in and then turn it all the way out to determine the amount of clicks that the adjuster has. A basic setting is between 12-16 clicks.
The general rule of thumb when playing with rebound adjustment is: the faster you ride, the faster the rebound needs to be. For example, if you casually roll through a set of whoops, the rebound can be set slow because there is plenty of time for the suspension to recover from each shock movement. But if you fly through that set of whoops, the rebound must be set faster to ensure that the shock returns to an unsprung state between each shock compression. If the shock doesn't return to the unsprung state, especially in a set of whoops, the shocks will "pack up," meaning they will be completely compressed and won't absorb anything, which will make the ride through the whoops extremely rough on you. To make the rebound action faster, turn the adjuster in (clockwise) and to make rebound action slower, turn the adjuster out (counter clockwise).
Test Yourself: Now that I've demystified suspension settings, there is one last step and that is to test different setups. The only way to learn how to set up your suspension better is by trying out different settings. The best way to start testing is by setting the rider sag at 30 percent at home in your garage, check the free sag, and then head out to your local ride spot with the necessary tools and a note pad.
As you ride, take mental notes as to how the quad handles certain obstacles. After you ride, write down those notes in order to make adjustments later. If you keep good notes of all your changes, it will become easier and easier to set up your suspension for different terrain and to maximize your quad's handling potential. A better handling quad could be the difference between a good day of riding and a bad day, so try out a lot of different settings. Chances are you will find a setup that you really like, which will make your riding time more enjoyable. Having your quad's handling tuned for you and your riding style (and by you nonetheless!) is much more gratifying than riding the standard factory setting that was designed for the masses.
