You can find the right oil in our shop, the right viscosity and quantity for your model also in the „Service“ area!

The old oil is removed using a commercially available vacuum pump, which was originally intended for brake bleeding. In addition to the pump, you only need two jacks, a folding rule, ratchet box and a torque wrench. The correct tightening torques for the corresponding screws can usually be found in the driver’s manual; alternatively, the authorized workshop can provide information.

Image 1:

In order to gain free access to the fork locking screw, it is often advisable to dismantle tubular handlebars. The front wheel and fork must be completely relieved.

Image 2:

A car jack or wooden blocks do a good job here.

Figure 3-4:

Be careful when opening the locking screws, as the springs could exert pressure on the locking mechanism from below. It is best to loosen with a ratchet. The preload sleeve and lock are removed. You should memorize the installation sequence of the components for later assembly.

Image 5:

Curved Allen keys or curved wires make it easier to recover the old springs. Many telescopic forks no longer have an oil drain plug.

Image 6:

Since we don’t want to dismantle the standpipes to let old oil flow out, a vacuum pump with a possibly extended hose is used.

If both fork legs are emptied, pumping movements on the front wheel prevent old oil from remaining in the leg. If you take it very carefully, you can sacrifice some fresh fork oil to thoroughly flush the system through. In this way, deposits can be kept in suspension and then sucked off again.

Important: As a rule, the fill level (the air chamber) is measured without fork springs and with the immersion tubes fully inserted.

Image 7:

A second jack is great for lifting the front wheel up.

Image 8:

Now both bars can be filled with fresh oil. To vent the system, the fork should be compressed several times.

The filling level of the fork oil determines the height of the air cushion above it, which has an influence on the damping properties (the thicker and thus the higher the SAE value, the higher the rebound (rebound) damping, i.e. the slower the rebound).

Usually the level is measured from the top of the standpipes. It is often difficult to determine the correct size on a folding rule.

It is easier if the height of the air cushion with a syringe and a universal aluminum adjustment tube with a lasered adjustment scale (available on our website: www.wirth-federn.de ) is set precisely. Excess oil is sucked off appropriately. If the filling level is correct, the front wheel can be lowered again.

Fig. 11-12:

The new spring is inserted with the progressive tight winding upwards. Before closing the bars, it is important to insert steel rings and spacer sleeves in the correct order – basically the old overall length of the original springs plus, if necessary, original sleeves should be achieved again, so it is best to place them next to the new springs. If these are as long as the old springs including the sleeves, the new spring is installed alone.

Image 13:

If a sleeve is installed, a suitable washer should be placed between the spring and the sleeve (Fig. 12).

Great care must be taken when assembling the screw plugs. A lot of feeling is required to apply the easily destructible aluminum thread against the spring pressure. Wrenches are not very suitable for this. Pressing it down and placing it straight on the thread works best with a ratchet extension and a socket wrench. Professionals feel beforehand without a spring the point at which the screw plug grips in the standpipe thread and mark the position with a pencil line over both parts.

The usual preload (required compression of the fork springs) is around 20 mm.

The first turns of the thread should be screwed in carefully, without a ratchet, only by hand. Finally, the lock is tightened with the appropriate torque, then the handlebar comes back into position. Have fun with the new experience!

By the way: You can also get first-class TECNOGEL motorcycle batteries, TECNOSparks spark plugs from our sister company TECNOParts and much more in our shop at www.wirth-federn.de !!