Not to rain on your parade….but just randomly turning the rear preload to “see how it feels” is a complete waste of time.
Suspension adjustments are a systematic process, which require a defined step-by-step method for setting up the suspension for your weight and riding conditions. First check the sag and then start turning stuff.
It’s all rather easy once you do it and will get you thinking about handling….which hopefully will make you a better rider.
Here ya go..........Dale’s Sportbike Suspension Set-up Guide
Honda 600rr front & rear travel is listed as 4.7” or 119.38 mm. Assume 109 mm to calculate “usable travel” percentage as below. This gives a 10mm safety margin for bottoming out type pot holes.
Rider Sag: The general rule is that rider sag should be approximately 25% to 33% of the “usable” travel. 109 mm / 33% = 36 mm. The front rider sag should be more then the rear. There is quite a spread of published recommendations so….
Rider Sag FRONT - 32 mm to 38 mm REAR - 25 mm to 32 mm
1) First, set all suspension adjustments as per manuals recommendations.
2) Ride the bike to warm-up suspension oil and simulate actual conditions. Have two people to assist. One to hold/balance the bike, another to measure and record data.
3) REAR SAG: Extend the rear suspension completely by getting the wheel off the ground. The bike can be rocked up on the stand to unload the suspension. Measure the distance from the axle to some point on the frame. This measurement is L1.
4) With rider on bike in full gear, balance the bike from the front. First, push down on the rear end about 25mm (1") and let it extend very slowly. Where it stops, measure the distance between the axle and the mark on the chassis. Do not bounce! This measurement is L2.
5) Lift up on the rear of the bike about 25mm and let it down very slowly. Where it stops, measure it. This measurement is L3.
6) Calculate rider sag. TOTAL SAG = L1 - [(L2 + L3) / 2], and adjust preload to equal 32 mm.
7) FRONT SAG: Extend the fork completely and measure from the wiper to the bottom of the triple clamp. This measurement is L1.
8) With rider on bike in full gear, balance the bike from the rear, then push down on the front end and let it extend very slowly. Where it stops, this measurement is L2.
9) Lift up on the front end and let it drop very slowly. Where it stops is measurement L3. Note that stiction or drag in the seals is particularly high for telescopic front ends.
10) Calculate rider sag. TOTAL SAG = L1 - [(L2 + L3) / 2], and adjust preload to equal 38 mm.
11) STATIC SAG: The next step is to check the static sag to determine if the springs are correct for the rider’s weight. With the bike off its stand, you should be able to lift just slightly and top out the suspension. If the bike is topped out at rest, a stiffer spring, is needed as a lot of preload has been dialed in to achieve the correct rider sag. Alternately, if the bike has a lot of free sag (you can lift the rear a bunch before it tops out), a softer spring is needed.
Static Sag FRONT - 15 mm to 30 mm REAR - 5mm to 10mm
12) FRONT REBOUND: With the bike at rest and off of the stand, firmly push on the triple clamp (don't hold on to the brake or push the handlebar, or seat). When you let go, the suspension should rebound quickly to its original position, but not beyond. If it takes more than approximately one second for the suspension to return to position, less rebound damping is needed. If the fork or shock over-extends past its free (static) sag, and then compresses again, more rebound damping is required. For street riding it is better to error on the soft side if you are unsure.
13) FRONT COMPRESSION: See below comments, but initially set it firm.
14) REAR COMPRESSION: Initially set a bit soft to facilitate the 60/40 weight split transfer required for optimum grip during balanced throttle...
15) SUSPENSION BALANCE: Stand next to the bike and hold/balance the bike upright. With one foot on the peg, give a good push down and have someone watch the reaction. A well-balanced setup will have both ends of the bike compressing and returning at the same rate. If not adjust the rear rebound/compression to compensate,
16) MEASURE THE TRAVEL: Measure the amount of available travel actually used while riding. Put a cable tie on the fork leg as well as on the shock shaft, and then ride the bike. If you find the cable tie is pushed up against the end of the shaft, the suspension is too soft. On the other hand, if the cable tie is only half way along the suspensions travel, chances are that the suspension is too hard. Ideally the swept area (total amount of travel used) is slightly smaller than the total travel available.
SPORTRIDER MAGAZINE :
Front Preload-3 lines showing, Front Rebound-1 turn out. Front Compression-1. 5 turns out, RearPreload- Position4 of 8, Rear Rebound - 0.5 turns out, Rear Compression- 6 clicks out.
Key points to consider
The viscosity of suspension oil varies with temperature so the suspension may feel firmer on a cold day or early in the ride.
Fine-tuning of compression & rebound is a small part of the picture and only come into play when everything else is properly set. The dampers are there to dissipate energy in the springs at a controlled rate and can only be properly set when everything else is correct.
A Sportbike will have about 5 times more rebound damping than compression damping due to the suspensions need to react to bumps quickly, yet return to the original position much slower.
There's a common misconception that adding preload combats excessive front-end dive, but actually, stiffer springs or extra oil fork oil are the cures.
Sufficient sag, especially in front, is necessary to allow the suspension to extend after bumps. Sportbikes are powerful enough to squat the rear suspension under acceleration and front sag will keep the front end in contact with the ground.
Most Sportbikes come with too-soft springs and must be excessively preloaded to achieve the proper sag. This results in a suspension that is too firm in initial movement and then too soft through the rest of the travel--exactly the opposite of what you want. If so and stock springs are retained, compromise, settling for slightly more than optimum sag in order to reduce preload; too much preload can override the suspension's rebound-damping capabilities.
Compression (Front) Too much in the front will cause a lot of chatter in the handlebars when not braking, or under light braking. (Springs are loaded and the hydraulics won't keep up).
Compression (Rear) Too much in the rear will cause wheel skipping--the wheel feels very light.
Rebound (Front) Too much is evident, especially in the forks, if you've also got a lot of chatter, but the difference is that it is following the bumps--the suspension is absorbing the bump, but then 'packing' and not riding down the backside.
As a rule
Too hard: If the damping is too hard, the bike will feel unstable. If it's too hard in the compression damping the suspension will not comply with bumps, as the transferring of the force is too slow, meaning the wheel will tend to skip over the top of the bumps rather than follow the contour of the road surface. If too hard in the rebound damping the bike will tend to 'pack down' or 'squat'. This is caused by the suspension not allowing the bike to rise back up to its original position quickly enough. The end result of this is sometimes referred too as suspension "chatter." Although the bike will feel unstable, it will tend to feel quite stiff or taught.
Too soft: The interesting thing here is that if the damping is too soft, the bike will also feel unstable. Only this time, rather than 'chattering' it will tend to feel 'sloppy,' and possibly 'wallow' in corners. (Wallowing means that the suspension will oscillate without anything seeming to start it off, like bumps for example) It may also feel a little like a pogo stick, continuing to transfer the force up and down the length of the travel. This is particularly noticeable on bikes that have done a lot of miles.
Just right: If the damping is working correctly, you probably won't notice anything! The suspension will keep the wheels moving up and down as required to keep the tires on the ground and the bike stable.
Suggested by Performance Bikes magazine Oct 03 (Full hard is all the way to the right or clockwise).
REAR SHOCK: Preload - position 4, Rebound – 1 ¼ turns out from full hard, Compression - 5 clicks out from full hard
FORKS: Preload - 2 lines showing, Rebound - 2 turns out from full hard, Compression -1 ½ turns out from full hard
TIRE PRESSURE: Street -34psi (front) / 39psi (rear), Track - 31psi (front) / 30psi (rear)
