Here's a breakdown of the process and tools you'll need:
1. Gather Your Supplies:
* Fork seal kit (includes new seals, dust wipers, and sometimes fork oil)
* Fork oil (the correct viscosity for your bike - check your owner's manual)
* Shop manual (highly recommended for detailed instructions and torque specs)
* Socket set (including 17mm, 19mm, and 22mm sockets)
* Adjustable wrench
* Torque wrench
* Pry bar
* Small hammer
* Rubber mallet
* Cleaning rags
* Shop towels
* Container for old oil
* Safety glasses
* Gloves
2. Preparation:
* Park the bike on a level surface and secure it with a wheel chock.
* Remove the front wheel.
* Loosen the axle nuts (not completely removed yet).
3. Disassemble the Forks:
* Support the forks with a jack or lift to prevent them from falling.
* Completely remove the axle nuts.
* Remove the fork legs from the triple tree (upper and lower).
* Remove the fork caps (usually held in place by a snap ring).
* Carefully pull out the inner fork tubes (the springs and internal parts will come out with them).
4. Clean and Inspect:
* Clean the fork tubes, slider tubes, and all internal components.
* Inspect the fork legs for wear and tear, especially on the inner tube.
* Replace any damaged or worn components.
* Use a measuring tool to ensure the fork tube is straight.
5. Install the New Seals:
* Place the new dust wipers onto the fork tubes.
* Carefully install the new fork seals onto the tubes. Use a thin layer of grease on the seal lip to aid in installation.
* Tap the seals in place using a rubber mallet.
* Be careful not to damage the seal lip.
6. Reassemble the Forks:
* Install the internal fork components (springs, spacers, etc.) back into the fork tubes.
* Apply a thin layer of grease to the fork tube sliders and install them into the fork legs.
* Carefully lower the fork tubes into the triple tree.
* Replace the fork caps and tighten them to the correct torque.
* Install the axle and tighten the nuts to the correct torque.
7. Refill with Fork Oil:
* Fill the fork legs with the correct amount of fork oil.
* Check your owner's manual for the correct viscosity and quantity of oil.
* Pump the forks up and down several times to distribute the oil.
* Ensure the oil level is at the correct level.
* Reinstall the front wheel and tighten the axle nuts.
8. Test Drive and Adjust:
* Take a short test drive and check for any leaks or issues.
* Adjust the fork height and preload as needed.
Important Notes:
* This is a general guide, and your specific model may have variations. Refer to your shop manual for specific instructions.
* If you are unsure about any part of the process, it's always best to seek the help of a qualified mechanic.
* Using the correct tools and techniques is essential to avoid damage to your forks.
* Take your time and work carefully.
Additional Tools:
* Fork seal installer tool: This can help to avoid damaging the seals during installation.
* Fork spring compressor: Makes compressing the fork springs easier and safer.
* Torque wrench (essential for properly tightening the fork bolts and nuts).
By following these steps, you can successfully change the fork seals on your 1981 Honda CM400 Custom. Be sure to consult your owner's manual and/or a qualified mechanic if you have any doubts or concerns.
