HOW-TO GUIDES & TUTORIALS | DBH SPAIN, 2021
Bearings play a pivotal role on your motocross or enduro bike, and that's why it's important to ensure they're adequately greased to keep key components protected, lubricated and moving as they should.
Which bearings should I inspect and grease?
Linkage and swingarm
What are the signs of wear and tear on bearings and how to check?
Steering head: There are two tapered roller bearings or on some models ball bearings in your steering head, and if these wear out they will affect your steering by either making it notchy, heavy or even locking completely. You can check this easily by having the front wheel of your dirt bike off the ground and slowly moving the steering from left to right and right to left, feeling for any notches or heaviness along the way. The second thing to check while the wheel is off the ground is to attempt to pull the front wheel out from the bike, feeling for any movement back and forth.
Wheel bearings: Front and rear-wheel bearings can run the risk of seizing and locking inside the hub without proper lubrication, which could end up destroying the hub if left unattended. When dirt bike wheel bearings start to fail, they will either stop the wheel from spinning freely or they will be excessively loose and your wheel will have lateral movement. To check wheel bearings, have the wheels off the ground and attempt to move the wheel side to side, checking for any movement. The second way to check is to spin the wheels and listen/feel for any rumbling in the bearings. Lastly, you can remove the wheels and inspect the bearings using your fingers to move the bearing and check for any notches or grit inside the bearing.
Linkage, swingarm and shock: There are a number of needle roller bearings in the back end of a motocross bike, and depending on the brand and model, they are located at the top and bottom of the rear shock, in your suspension linkage, and in your swingarm. If any of these fail, they can severely affect your dirt bike's suspension performance or even seize it completely. When they start to fail, you will notice excessive free play and movement in your swing arm and reduced rear suspension performance. This is when you'll need a new swingarm bearing kit and/or swingarm linkage bearing kit. To check linkage and swingarm bearings, you will need to have the rear tyre off the ground and lift the rear wheel, feeling for any notches or movement. If you have a helper, it is also handy to hold the lower linkage body and shock to feel for any clunks while the rear wheel is being lifted.
How to pack bearings with grease?
Packing bearings is a simple process that involves gaining access to the bearings, cleaning with a contact cleaner and re-greasing them with fresh waterproof grease. Depending on the bearing you are trying to pack, your technique will vary. Tapered roller bearings: Found most commonly in steering head bearings can be easily packed by smearing a layer of grease on your hand (wearing disposable gloves is a must) and pushing the grease inside the bearing between the rollers and the outer cage by sliding the bearing over your hand. Needle roller bearings: Found commonly in suspension components such as your linkage, swingarm and shock requires grease pushed inside them by removing the inner sleeve and packing it full of grease. Note: Be careful as the needle rollers aren't held in when the inner sleeve is removed, and sometimes they can fall out. Always apply grease or anti-seize to all axles and bolts that run through the bearings, this will allow easier removal next time you regrease your bearings. Just remember you can’t hurt your bike by over greasing it, you may make a mess, but your bearings will be far better off being packed with grease than being run dry or full of water, rust and grit.
How do bearings wear out?
Bearings are one of the hardest working parts (outside your engine) on your dirt bike, being exposed to extreme friction, heat and force. All of these factors will end up destroying the bearings eventually, however, the nature of dirt bike riding reduces the life expectancy substantially. We all love to ride our dirt bikes through sand, mud, water and any other nasty outdoor element you choose to encounter, and once these elements work their way inside your bearings they cause extra friction reducing the life of the bearing.
If your bearings are packed regularly with good quality, waterproof grease, this will reduce the amount of friction inside the bearing while limiting the amount of dirt and grit that can get inside, increasing the life of your bearings.
The necessity of waterproof grease is to keep the water out of your bearings. Water can enter a bearing when going through puddles, creeks and even when you wash your bike - when water gets in, it isn’t easy for it to dry or get out, and if water is sitting inside a metal housing for too long it will begin to cause rust - and you can imagine what rust will do to those moving parts!
How often should I inspect and pack my bearings with grease?
Inspecting your dirt bike's bearings should be a part of your regular routine maintenance and should take place every time you clean and prep your bike.
It's common knowledge that new bikes was assembled in the factory with little to no grease packed into their bearings, which is why many riders will strip them down and grease them up before hitting the track on their fresh steed. If you have purchased a new dirt bike, we highly recommend greasing your bike before you ride for peace of mind.
Many riders will grease all components on a regular basis, usually carrying this out at least every 6 months, depending on how often they ride and the conditions they ride in. Factory teams will grease their bikes far more often to reduce the likelihood of a potential failure. Please refer to your owner's manual for specific time frames for inspecting and greasing your bearings on your model.
Some of the best quality oils and lubricants at MXstore:
Oils and Lubricants
If you have any further questions about bearings or motorcycle maintenance, don’t hesitate to contact our friendly team at MXstore