The fork of the motorcycle connects the wheel and the front axle to the main frame; it allows the driver to change direction, acts as a shock absorber and contributes to braking operations. The piece consists of two tubes, each of which needs a gasket (oil seal) to hold the oil inside and prevent spills. Oil seals should be replaced as soon as leaks are noted; if you do not act promptly, the oil will penetrate into the brake pads with dangerous consequences or it could run out completely and damage the motorcycle. Follow the article instructions to change these gaskets.
Step 1. Prepare the motorcycle for maintenance work
- Loosen the two bolts that secure the caps to each leg and these to the frame; then, unscrew those of the brake caliper and remove the entire axle from the bike.
- Shift into first gear and wedge a wedge behind the rear wheel.
- Raise the front wheel to the required height.
- Remove the brake calipers, fender, front wheel, and any dangling cables.
Step 2. Remove the fork
- Loosen the bolts further and pull the fork forward as you rotate it.
- Remove the cap carefully; remember that it is under the pressure of the spring, so avoid getting in its path while you take it apart.
- Pull out the spring and let the oil drop into the bucket.
- Remove the shock absorber stem by inserting a tool into the cavity to reach it.
- Try to memorize the arrangement of the springs, washers and spacers in order to fit them correctly later.
Step 3. Remove the old oil seal
- Pry to detach the dust seal from the leg.
- Locate the actual oil seal; is held in place by a clip in a notch.
- Gently pry to release it.
- Clean the area to get rid of any debris found in the fork.
- Take the stem with one hand and the scabbard with the other; exert some force to separate them, you should notice that the gasket comes out of its housing.
Step 4. Prepare the fork for the new oil seal
- Remove all rust and repair any blemishes that caused the previous leak.
- Wet a rag with oil and rub it on the area where the gasket rests.
Step 5. Install the new oil seal
- Grease the inside.
- Place the gasket over the scabbard and slide it down into place.
- Position the oil seal correctly with the dedicated tool; by doing so you ensure that it is placed securely.
Step 6. Refit the fork
- Put the clip and dust seal back into their respective slots and slide the shock stem inside.
- Pour in new oil to the required height.
- Reinstall the spring and screw in the cap, then tightening the bolts.
Step 7. Repeat the same process for the other leg
Step 8. Reassemble the front of the motorcycle
- Replace both oil seals at the same time, regardless of whether only one is damaged; in this way they "age" together.
- Instead of using physical force to separate the stem and remove the oil seal, fill it with oil and apply pressure to "pop" it off.
- Using a front wheel stand is the safest way to lift the motorcycle during maintenance work.
- If you cannot repair the damage hidden by the old oil seal, the entire shaft may need to be replaced.