Fork Installation Tips To Reduce Stiction
Ensuring the proper fork installation methods are used and torque specs as can be found in a factory service manual specific to the motorcycle being serviced are used when reinstalling the forks on a dirt bike, such as after servicing the steering head bearings, or when reinstalling the forks after having a service performed to the forks such as an oil change, re-valve or even having the fork seals replaced will ensure the forks are parallel from top to bottom, and thus reduce any chances of excessive “Stiction” (Stiction is a slang term for sticking and friction which can cause harshness of the fork's travel, as well as accelerated wear of internal bushings)
Additionally, even if the forks are not removed from the dirt bike, it is still a good idea to occasionally loosen the triple clamp pinch bolts, axle pinch bolts (or nuts), and the axle itself and then re-tighten the triple clamp bolts, the axle pinch bolts (or nuts), and the axle itself as outlined below, as this will reduce the stress on the forks internals and allow the forks to realign in the triple clamps, and this is especially true if you're known for crashing or tagging trees.
Before you begin the fork installation, it's a good idea to ensure that the steering head bearings are in good shape, well lubricated and properly adjusted, as well as to remove all the pinch bolts from the triple triple clamps and axle pinch bosses and apply a coating of anti-seize to the threads.
Once you have the steering head bearings lubed, and all the pinch bolts coated with anti-seize, check out the fork installation steps below.
How To Ensure Proper Fork Installation
- First, install the fork legs into the triple clamps ensuring you have the fork leg with the brake caliper mounting boss on the proper side, and to ensure that the fork legs are of the same height, and the overlap of each fork is at equal heights. There is more on fork overlap here, then ensure that the bleeders are positioned towards the front, as this will make bleeding air from the forks in the future easier.
- Once the fork legs are installed in the triple clamps, work on tightening the triple clamp pinch bolts in an alternating fashion on one fork leg at a time, beginning with the top clamp of each fork leg, then the bottom until both upper and lower clamps of each fork leg are torqued to the value specified in a factory service manual specific to the motorcycle being serviced.
- Next, before installing the front wheel and axle, be sure to check the wheel bearing condition beforehand by inserting your finger into the inner race of the bearing and turning the bearings to feel for any roughness or play, and replacing the bearings if any rough spots or play are felt in the wheel bearings.
- Once the wheel bearings are inspected, apply a light coating of grease to the external area of any external wheel bearing spacers where they contact the outer wheel hub seals, then apply a light coating of the same grease to the front axle and install the front wheel and axle to the forks as detailed in our article on Installing the Front Wheel.
- Once the forks are installed and the front wheel is in place between the fork legs, if you have not already done so as instructed in the article on installing the front wheel, refer to a factory service manual specific to the motorcycle you are working on for the front axle torque specification and fully tighten the axle to the proper torque specification specified.
If you have trouble tightening the axle nut...
When tightening the front axle nut, on motorcycles where the axle end is flush with the bottom of the fork leg / lug, you're supposed to have a special hex shaped axle holding tool to keep the axle from turning, although if an axle holding tool is not immediately available, you can temporarily tighten the axle pinch bolts opposite of the side you are tightening to hold the axle from turning, although this should only be done in an emergency type of situation such as during a ride or if a holding tool is simply not immediately available.
If Working without an Axle Holding Tool, Always Loosen The Axle Pinch Bolts Immediately After Tightening of the Axle Nut.
Note: During the following steps, if you're working with a fork leg that has removable axle pinch blocks, be sure to check for any arrows or indicators of direction before re-installation of the cap to the fork leg and / or tightening of the pinch block.
- Continuing with the fork installation, the next step if the forks were removed from the bike is to reinstall the brake caliper and torque these bolts to the proper specification as can be found in a factory service manual specific to the motorcycle being serviced, but before doing so, be certain the threads on the bolts that mount the caliper assembly to the fork leg are clean, dry and free of any oily residue as well as making sure the internal threads on the fork leg where the caliper mounts are clean, dry and free of any oily residue, as well and then apply a small amount of red loctite (which can be found at most auto parts stores) to the threads of the bolts that mount the caliper assembly.
- Once the brake caliper is mounted to the fork leg, it may be necessary to squeeze the brake lever part way several times to bring the brake pads into contact with the brake rotor and achieve noticeable pressure at the brake lever, although if the brake pressure does not feel the best, be sure to see this article on bleeding the brakes.
- Once you have adequate brake pressure, spin the front wheel by hand and quickly grab a handful of front brake causing the front wheel to abruptly and momentarily stop while elevated, then repeat this process several times, as this will help to align the forks parallel.
- Once you have spun the wheel and stopped it abruptly several times, be sure you're off the brakes and tighten the left side axle pinch bolts (or nuts) to the torque specification that can be found in a factory service manual specific to the motorcycle you're working on.
- After tightening of the left axle pinch bolts (or nuts) spin the front wheel and quickly grab a handful of front brake several times again, then after releasing the brakes, tighten the right side axle pinch bolts or nuts and get this thing off the stand and loaded up, as that's all there is to proper fork installation that will ensure minimal fork stiction and optimum fork performance.
If You Want to Be Absolutely Certain of the Fork's Alignment, A Fork Alignment Gauge Will Ensure the Forks are In Proper Alignment