As racers, we know the important role that dirt bike fork springs play in the overall suspension, feel and control of the bike. Unfortunately, these integral components are not one size fits all, and some riders require more or less bounce to make their bike fit their riding style. Fortunately, swapping out your fork springs is a straightforward process requiring only a few basic tools and a little elbow grease.
The best part about fork spring replacement is that you can often do it without draining and replacing the oil. However, to ensure minimal spillage and also proper placement of the fork components, it is essential to follow the replacement process closely. Putting one component in wrong can not only cause a mess but may also damage your forks.
While replacing mx fork springs is not a difficult job, it is a precise job. In order to complete that job correctly, you should have at least some basic tools. However, more specifically, you should have access to the following:
- End wrenches
- Assorted sockets
- Flat blade screwdriver
- Rod holding tool (spare axle or screwdriver)
- Seal driver (possible without but better with)
The first phase in the how to change fork springs process is to dismantle the spring arm. Thankfully, you do not require a special area for this process, meaning that you can do this roadside, trackside or even in a parking lot. You don’t need lifts, vices or other fancy equipment, just the hand tools listed above. Also, to reduce the risk of oil spillage or drippage later on, you may want to stand the fork arm upside down, allowing the oil adequate time to travel into the upper tube. Once you have allowed some time, even five to ten minutes, you can begin dismantling the arm.
- Back out the rebound clicker
Every fork has a specific setting for the rebound clicker. While you are backing it out or turning it down all the way in this step, it is vital that you know and remember the original setting for reinstallation.
- Remove the rebound bolt and rod
Removing the rebound bolt and rod may require a vice. However, using the socket wrench and appropriate socket, you can loosen the bolt by using another axle screwdriver or wrench to hold the arm in place. Once loose, compress the lug to see the rebound rod and reveal the nut that countersinks against the bolt. You need to loosen this next with the right sized end wrench. Do this slowly. Loosening too quickly can cause damage. Remove the rebound bolt and the inner rod.
- Remove the seal and the retaining clip
Between the lower and upper tube, there is a seal and retaining clip. Keep the upper tube upside down, leaving the oil in that location capped off. Using the edge of the flat blade screwdriver gently pry up the dust seal of the lower tube. Take your time to avoid damaging the tubes. Now, remove the retaining clip that was under the seal by using your screwdriver and pressing against the lips/indents of the ring to slowly pull it up and out.
- Remove the lower tube
The only thing still holding the tubes together is the oil seal. To remove the lower tube, slide it up until you feel the resistance of the bushing bottoming out against the oil seal. Moving the lower tube up and down with a little force to tap down the seal until the lower tube is free. Now, you should have access to the fork spring, maintaining the majority of oil in the upper tube; although some oil will spill or drip out as you remove the upper tube. After this, the spring is exposed, and you can swap it out for your desired spring.
When reinserting the lower tube into the upper tube, it is crucial to get the oil seal set right. While you can attempt to do this using a screwdriver or forcing it back in, the best way to ensure a proper seal and to save yourself some financial headaches is to use a seal driver, which is the proper tool for this job. Place the driver around the tube and use it to press and tap the oil seal into place. You should be able to hear and feel when the oil seal has bottomed out. If you don’t feel it or are unsure, you can look to see if the channel for the retaining clip is visible and usable.
Once the seal is reset, you can return the retaining clip to its position. You can try to put the clip back in with your fingers, but the screwdriver is probably the easiest way. Take your time and make sure the clip is completed seated because it is what holds the oil seal in place.
After the retaining clip, you can replace the dust seal. Again, you might be able to use your fingers, but due to the multiple lips of the seal, using a screwdriver may be easier.
Last, reinsert the rebound rod and connect the rebound bolt. The rod has a D-shape that must be properly seated inside the tube. You will know when it is sitting correctly because it will slip down below the threads for the bolt. Reconnect the rebound bolt by compressing the spring and holding it in place with the end wrench, ensuring that the bolt is correctly seated before twisting it back onto the rod.
Once the bolt bottoms out and is turning the rod, tighten the counter sink nut and the rebound bolt against each other using the socket and the end wrench. Tighten everything before resetting the rebound clicker to its original position.
As you can see, a dirt bike fork spring replacement is not that complicated and is one of the few tasks you can complete on a bike without a proper shop and equipment. If you think you have what it takes, then go out and purchase the best motorcycle fork springs for your riding style, and get the job done.