Modded Raptors Forum banner
1 - 2 of 2 Posts

· Registered
33 Posts
Discussion Starter · #1 · (Edited)

Disclaimer: If any of this information is incorrect, please say so, I will correct as needed.


Your shock adjustments determine how well your machine handles bumps, how it corners, how it lands a jump, and most importantly, how comfortable you are while riding. Bad shocks and lack of proper adjustment can make you feel like you have been beaten to death out on the trails. A nicely well tuned suspension will allow to ride on harder terrain , for longer, and still feel much better after your ride than being beaten up by an unadjusted set-up.
The difference can literally be night and day.

To adjust the suspension of your 660R (and many other Quads) you need to understand the following 3 adjustments. The suspension will be “tuned” using these adjustments, and they are done in the order they are listed. See your owners manual for a brief description of where the adjusters are located.

1. PRELOAD: Preload is the amount of coil spring tension with a rider in place. On the 660R the rear shock is adjusted by the threaded ring collar at the top of shock’s coil spring. On a stock 660R front shock preload is the ONLY adjustment and is adjusted by the twist collar at the bottom, which has "steps" built into it and allows about 5 stepped settings. Upgraded front shocks, such as the YFZ shocks, are adjusted for preload like your stock rear shock, using a threaded collar.

2. COMPRESSION: Controls stiffness, how easily/quickly the shock will compress. When you hit a big rock the shock can compress faster (softer) or slower (harder) depending on how you have Compression adjusted. The top screw at the reservoir end of the shock controls the rate of Compression. It clicks as you turn it and you can count the clicks as a means to remember how much you have adjusted it.

3. REBOUND: Rebound is measured by the speed at which the shock returns to it’s normal state after being compressed. After hitting the big rock and your shock has compressed to absorb the hit, it must “Rebound” to be ready for the next compression. Rebound is adjusted by the Bottom screw, below the coil spring retainer and it also “clicks” as you turn it.

Note 1: The stock Rear Shock on the 660R has all 3 of these adjustments available, the stock Front shocks ONLY have the Preload adjustment. The YFZ front shocks are a popular replacement and have all 3 of these adjustments, as well. (Modification of shock supports is needed in order to mount the YFZ shocks to a 660R).

Note 2: Suspension adjustments are not absolute, they vary due to rider weight, type of terrain, amount of power at hand and the limits of your available adjustments. Any measurements given are general guidelines, ultimately, there is no magic setting that can be written down and used by all. It is a personal thing, it’s how you feel and your riding habits. Some like a stiffer ride, some like softer ride, some like a more springy feel, others don’t.

REAR Preload Adjustment also called "Ride Height Sag" adjustment *You will need a helper and your riding gear.

1. Lift the ATV by the lower frame (not the swingarm) so the rear tires are off the ground and the swingarm is hanging down.
2. Measure the distance from the top of the rear axle housing, or axle itself, straight up to a point on the frame, like where your grab bar bolts to the frame. But try to make it a point directly straight above the bottom point.
Remember this number!

THE MATH: "Ride Height Sag" should be about 30% of your total suspension travel. So, if your initial reference number was 15”, then you are looking for a total of about 4.5” to 5” of sag, when you are sitting on the bike, ready to ride.

Let’s continue...
3. Put the ATV back on the ground ready to ride. Put on all your normal riding gear.
4. Sit on the seat, boots on the footpegs, hands on the grips, in your normal riding position. If you normally carry a cooler on your back rack, put that weight on there also.
5. The helper can now take the same measurement between the same two points (rear axle housing up to frame) as the first measurement.
The difference between the 1st and 2nd measurement is called the "ride height sag".
6. Adjust your preload so that your "ride height sag" is about 30% of your total suspension travel.

Example: if the 1st measurement was 15 inches (axle housing to frame), and your helper then measures 9 inches when you are sitting on the ATV, you have a Sag of 6 inches (15” – 9” = 6”). This is about 40% sag, which is a bit too much. You would adjust the threaded collar so that the coil spring was a bit tighter, and take another measurement while seated until you get closer to 30% Sag.

FRONT Preload
Note: This is the only adjustment you have on the stock 660r front shocks.
Do the same as you did for the Rear sag, front tires off ground, tahe a reference measurement, then hop the ATV, take a 2nd measurment. The front "ride height sag" should be about 20% , or 1/5th of your total shock travel.

Since you only have the choice of about 5 settings on the stock 660R shocks, just get as close as you can, the stock front shocks are one of the weakest links on the 660R, you either have to deal with it, or find some better shocks. This is where aftermarket or the YFZ shocks come into play, and it’s why you read so much about riders changing the fronts to the YFZ shocks.

The compression adjustment as hard versus soft. This adjustment is one of “FEEL” , it would be difficult to give any kind of actual measurement. This the screw at the reservoir end of the shock, on the 660R is the TOP screw.
Soft compression means the shock is faster to compress, squishier. Hard compression is slower to compress, stiffer.
Adjusting the compression determines how quickly the shock reacts when the ATV’s tire hits an object. This adjustment is dependant on things like terrain and how you ride your machine. The objective of the compression adjustment is to tune the reaction time “rate of compression” to take advantage of the total travel of the shock, but, at the same time, keeping it from bottoming out too hard too often.

–If compression is adjusted too soft the suspension will feel too squishy under normal conditions. Too soft will allow the shock to bottom out hard, when striking an object, bump, or landing a jump.
–If compression is adjusted too hard, You'll feel every little bump you hit because the shock isn't absorbing the bump as it should, it is not taking advantage of it’s full travel to give you a better ride.

Compression is adjusted by FEEL, which means riding.

Counterclockwise = Softer/Squishier Clockwise = Harder /Stiffer

*Before you adjust the Compression: Before adjusting and dialing in the Compression, go to the Rebound adjustement, and set it somewhere in the middle. See below for how to adjust Rebound. Setting it in the mdidle will keep a harsh Rebound issue from messing with your head while you are adjusting your Compression.

Here is a way to adjust compression from SOFTEST on up:
Start by setting the compression at most Soft, turn the screw counter-clockwise all the way, then 1 or 2 clicks back clockwise (Never leave the compression or rebound adjustments Maxxed at one end of the other as it may actually close off the flow of fluid so much that it renders that adjustment useless).
Once set to SOFT, Ride for a few minutes on a smooth surface. Next ride over some smaller bumps. It should feel squishy, and have a feeling of floating. If you hit a sizeable bump now, at speed, you will probably bottom out easily.

Adjust the compression to absorb the bumps without feeling mushy or squishy. As you adjust the compression on the shocks, gradually begin moving up to bigger bumps and/or jumps. Every time you progress to larger jumps and bumps re-adjust the shocks to get rid of any squishy feeling. Adjust until you reach the point where you have reached YOUR personal limit of bumps or jumping safely while using all the travel in the shocks.

Compression and Bottoming out:
It's ok if the shocks “bottom out” as you land your largest jump or hit your largest obstacles. BUT, they should only bottom out a very small amount, just barely. This is how you know you are using as much of your shock travel as possible.

Opinion on Bottoming and adjusting for it:
My personal opinion about compression and bottoming out is, If you ride hard all day long, hitting good sized bumps and /or jumps and never bottom out once, you probably need to adjust your compression a little Softer. On the other hand if you ride hard all day long, if you bottom out numerous times, and one or two of those times are hard, enough to really get your attention or rattle your teeth, then you might need to adjust a little more Hardness into your compression.

Rebound is how fast the shock returns to its normal position after compressing. Faster or Slower. On the Rear Shock of the 660R rebound is adjusted with the bottom/lower screw , below the coil spring.
Sometimes you may hear the terms Hard and Soft used for Rebound, just like compression.
I am refraining from using it here, so as not to confuse it with Compression. Fast and Slow better describe what the shock is actually doing. You are actually dampening the effect of Rebound, since the coil spring wants to snap back to normal.

Fast Rebound = Less dampening Slow Rebound = More dampening

Same as compression, the screw will “click” as it’s turned. There are approx. 20 clicks total.
Never leave the Rebound screw turned all the way “IN” (Clockwise) , the MAX setting is going to be about 3 clicks from all the way “IN”. If screwed in all the way, you may shut off flow so severely the shock will not function correctly.

Setting the shock to rebound rapidly (FAST) allows the shock to return to it’s normal position more quickly.
Why is this a problem?
Don’t we want it to snap back quickly ready for the next bump?

BUCKING: At the Fastest adjustment setting the ATV may feel like a pogo stick. As you ride over a bump, a rear shock that returns too quickly may rebound with a similar but opposite force as the compression hit, pushing the rear of the machine up and wanting to send the rider over the bars. This is called “BUCKING”.

Setting the rebound to it’s Slowest (more dampening) , retards the return of the shock to it's normal position. At this setting as you speed over the bump the shock may not return to the normal position fast enough causing the shocks to "pack up".

PACKING: The more the shocks "pack up" The less travel they have until they have a chance to return to their normal position. An example of Packing goes like this, you hit the first bump and while the shocks is rebounding, it hits the second bump before it is fully back to normal, so it has less total travel, and so on as it hits each successive bump. At it’s worst, “packing” can keep happeneing over a series of bumps until you have no shock travel left at all. It’s like your shock gets shorter and shorter and dies.

The best way to set the rebound on your shocks is to find a set of "whoops". A series of rolling hills two feet high and six feet apart. Since we all don’t have access to actual whoops, just find a spot that has a decent series of bumps like you normally may encounter on a ride.
With the adjustment at full FAST return (screw all the way OUT / counterclockwise) , ride through the whoops at a slow speed. Repeat, and each time you ride through the whoops go through with a little more speed. With an increase in speed, you will start feeling a pogo or bucking effect. Adjust the Rebound toward Slower (clockwise) until you reach your fastest comfortable speed, with the shock returning to it’s normal position (not packing), and not bucking. If you go too far to the Slow end of the adjustment, the shocks won’t return quick enough for the next bump (packing) , and you may even feel it bottom out more, or just not suck up as much of the hit, since it has shortened the travel by not returning fully before the next hit.

After thoughts:

-THE BIG MISTAKE Riders who feel bottoming occur will quickly start fooling with their compression. You must be able to recognize the difference between bottoming due to packing vs. bottoming due to soft compression.
A. If you bottom out, after running over a successive series of bumps, it’s most likely “packing” and is probably a Rebound issue.
B. If you bottom out on a single hard hit or jump, then it’s most likely a Compression issue.

-A word of advice: Don’t make multiple adjustments simultaneously! Don’t turn your Compression XX number clicks and your Rebound YY number clicks and then go ride. Make a single adjustment, ride, and see if it changes the one thing you are feeling. Then proceed to the next adjustment.

-After going through all 3 adjustments as described above, Preload, Compression, and Rebound, back up, and check your Compression adjustment once more, maybe it needs a tweak, and then once more on your Rebound, and again, it would be a tweak.

-IF YOU CHANGE YOUR PRELOAD YOU MUST re-adjust your Compression and Rebound.

Final Words: Tuning your suspension is personal. It’s your weight, how you ride, and the terrain you typically ride on. After making your initial adjustments, go on your next long ride, and if need be, you can tweak your settings to “dial in” to your best adjustment for that terrain.

A well adjusted suspension can make your riding more pleasurable, give you more control, and your arms and shoulders won’t feel so sore. You will feel less beaten up at the end of a long day or weekend of riding if you have adjusted your suspension properly.

· Registered
6 Posts

2. Measure the distance from the top of the rear axle housing, or axle itself, straight up to a point on the frame, like where your grab bar bolts to the frame.
I think you need to make the measuring point VERY exact. Here's why. If Joerocket measures from the top of the axle housing to say, the bottom of the battery box, he could get 10.75". Or he could measure from the top of the axle (before it flares out at the sprocket) to the top of the coolant recovery tank lid and get 21". This difference in measuring could easily cause a 3" difference in the sag he sets, based on the 30 %.
1 - 2 of 2 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.