The suspension responds accurately to city/sports riding and inconsistent road conditions. It also allows you to focus more on riding.
It requires smooth movement of the links that convey the movement of the fulcrum pivot and rear tires to get the most out of that ability. Disassemble and grease up the working parts before you feel like, "Oh, the suspension is improving".
"Hard" and " tough" are two entirely different things.
The characteristic of a linked suspension is that the stroke of the rear tire is not proportional to the stroke of the shock unit. The reaction force of the spring is small and the shock unit shrinks in a quadratic curve, and the reaction force becomes large when you take a large stroke while cornering because the shock unit doesn't shrink much in areas where there is little up and down movement of the rear tire. This is called a progressive characteristic.
The function of the suspension is important for motorcycles, as the body posture can vary greatly like in full acceleration, hard braking, and cornering with knee scraping. Some riders may have switched to aftermarket shock units because of the combination of load bearing springs and damping force that suppresses excessive movement makes comfortable ride around town and a firm ride on the winding roads.
There has always been a mood to focus on whether it's hard or not when evaluating the suspension. Many riders say it's sportier to have a tough suspension stop quickly than a fluffy move when you hold the handlebars of a stationary motorcycle or sit on the seat.
Each spring built into the suspension has its own standard, called a spring constant. It is a value that indicates how much the spring will shrink when a load is applied to it (or, in the case of an extension spring, how much it will stretch). The spring with a small spring constant will shrink under low loads, and the spring with a large spring constant needs a large load to shrink.
This is why a suspension with a built-in spring that has a large spring constant feels stiffer when pushed with the same amount of force. Meanwhile, it is the parts that transmits tire movement to the shock unit, and it should move smoothly regardless of the spring rate of the shock unit if it is a rear suspension, no need to be worry about the swingarm pivots and links. These bearings are consist of a shaft and bushing or collar and bearing, which must be lubricated with grease.
I am interested in branded shock units but there are few riders who do not care much about the maintenance of their links and pivots. It can be misinterpreted as a hard and sporty rear suspension that is not moving well due to lack of grease but only users can be able to use it. For handling of large loads, it is important to know that stiff springs and damping power are not the same thing as reluctance due to lack of lubrication.
- The rear suspension needs movement even is sports riding.
- I don't get confuse about the stiffness of the rear shock with reluctance to move.
Poor lubrication can cause shafts and bushings to burn out.
The swingarm is removed from the frame when the swingarm pivot shaft is removed after the removal of the links and shock unit. It is necessary to have a stable jack to support under the engine because there's nothing to support around the rear part.
The swing arm pivot and link bearing section has different ranks of bushings, collars and bearing combinations depending on the motorcycle engine displacement, category and grade. There are no bearings in the axle for low speed and low load motorcycle, such as moped class motorcycle. Also, it seems like many models of older vehicle -1970 are still using bushings instead of bearings even for heavy type motorcycle.
On the contrary, the use of multiple bearings on the swing arm as well as on the link bearings has significantly increased awareness of reduced friction in the bearings when the model becomes a new model that emphasizes sports performance.
The reason for this is clear. It is necessary to convey even the smallest changes in load when the car goes over small bumps to get the best performance out of your shock unit. We want to eliminate as much resistance as possible from the linkage and swing arm pivot as a relay point.
The shock unit is capable of handling a load change of 0.1 as the change in load as a 10-point scale from 1 to 10. Expensive shock units are also important. If the links and swing arm pivots are stiff due to lack of lubrication, they need to add a load of 2 to start moving.
It is easy to see if you stroke the swingarm up and down that removed the rear tire and shock unit to determine the lubrication status of a link. Just make sure it runs smoothly. That thing doesn't go down without releasing the hand that's holding the swingarm. It's much heavier in the stroke range, feeling crisp and crunchy with no smoothness of movement, and there may be a problem somewhere in the bearing when you get stuck in the middle.
The swingarm pivot shaft is not in direct contact with the swingarm bearings. The swingarm pivot shaft is in contact with the bushing (sleeve). The majority of the shaft's surface finish is unichrome, and that's the motorcycle that's just to be ridden regardless of the weather, and the rain and wind can rust the surface of the shaft and make it hard to pull out.
It's not a rotating motion like a wheel or crankshaft. The swingarm or link is a pivoting motion that moves back and forth over a certain area. The bearing is subjected to high forces in certain areas. Therefore, in case of insufficient lubrication, the hard chrome plating layer on the bushing surface can be scraped off in areas where the bushing hits hard. In some cases, the symptoms are like burning.
The dust seals on the bushings and bearings may break, allowing water to penetrate and cause damage. At the same time, lack of lubrication = lack of maintenance. There are some cases where the pivot bolts and collars have become rusty and can't be removed, so be careful.
- Heavy loads can move with poor lubrication
- It is the link that tells you exactly what to do even for small changes.
It is tightened to the proper torque after disassembly and grease up.
The pivot section uses a needle roller bearing with many thin rollers. The oil seal is set on the outside of the bearing and a seal cap is lightly pressed from the outside. The grease on the needles should be scrubbed off with a toothbrush while spraying with parts cleaner.
It will be restored with an application of extreme pressure grease it will be restored with an application of extreme pressure grease. This part, which connects the swing arm to the frame and rear shock, is called a rocker arm. The position of the three bolts determines the progressive characteristics.
It goes without saying that the components involved in the suspension are very important, so the bolt diameter is thicker and has larger tightening torque. The swingarm pivot shaft nut is specified as 80 N/m, and each nut of the link part is specified as 70 N/m in case of using KAWASAKI GPZ400F introduced in the image.
It is not a problem to loosen it while riding because the tightening is weak, but it doesn't mean that you should tighten it hard. Abnormal tension is applied to the screw part if you tighten it with ridiculous power, which causes a problem with durability. It is not owned by every motorcycle riders but it's true that using a torque wrench improves work reliability.
It is important to ensure the stability of the motorcycle because you will have to loosen a tight nut or, conversely, tighten the nut with strong force. Prepare the stand and front forks by tying them together with a rope or tie-down belt in order to prevent the stands won't come off without the rear tire and swingarm even on models with a center stand.
Also, for motorcycle that only have side stand, it is necessary to support the engine and the footpeg are from underneath in order to remove the swingarm because it cannot use a racing stand. There are jacks available for this purpose.
Thoroughly clean with a parts cleaner and check the collar and bearings for damage. after removing the link and swingarm. At this time, the oil seals and O-rings on both sides of the swingarm and linkage bushings were worn out. I'll check to see if there are any.
If the seal is damaged, the grease on the sliding parts will be washed away by water when driving under the rain. So, the effect is not long-lasting even if you try to maintain it.
In some needle roller bearings, the needle is detached from the bearing case that is line of a fine needle-like rolls lined up in the bearing. Please be careful when pulling out the bushing, as the needle may fall out.
You may want to disassemble it on a parts tray or something else to avoid losing a dropped needle if you're not sure if your motorcycle is the right type you have.
Each part that is removed is carefully cleaned and greased to restore it. We're going to use the same thing here, which is the ability to maintain lubrication even when it's pressed down hard. It is recommended for extreme pressure grease. Molybdenum disulfide grease and urea grease are recommended.
It is just a matter of putting each part back together and tightening the bolts and nuts with a torque wrench, then recheck the movement of the swingarm before installing the unit. You will be amazed at how light and smooth it runs, the less maintenance you've done on the bike, the better. You may feel like the suspension is softer than it was before you took it apart but that movement is the result of the maintenance of the links and swing arm pivots when the shock unit is installed and the rear suspension is stroked.
This effect can also be experienced with twin shocks, so owners who haven't touched it for years should check it out! Let's try it.
Tighten the bolts to the torque specified in the service manual before installing the shock unit. Make sure that the swing arm moves up and down smoothly by moving the swingarm up and down when assembling it.
- It ensures lubrication with extreme pressure grease.
- It is important to tighten the bolts with the proper torque when restoring it.