Routine servicing of the swingarm and linkage bearings, as well as the pivots at each end of the rear shock(s) on a modern, or vintage style dirt bike is something that is supposed to be considered routine dirt bike maintenance, but It's pretty well known that servicing swingarm and linkage bearings, as well as service of the shock absorber(s) / damper(s) pivots is something that is commonly put off until "next time" on a lot of dirt bikes, so this article is written for those with vintage style bikes or modern weaponry, (linkless bikes included) to get their rear suspension dialed and any slop gone.
It's no secret that servicing and lubricating the rear suspension of a dirt bike on a regular basis can provide a smoother ride, and a better handling or more predictable motorcycle the next time you're railing berms and charging into some of the deepest, gnarliest braking bumps at a motocross track, as well as a well lubricated rear suspension can provide a better ride next time you head out in the woods for a Trail Ride, GNCC Race, Hare Scramble or Enduro.
If you routinely pressure wash the bike when cleaning it, frequently ride sections where there is mud and water, or you just don't know or remember the last time that the swingarm and linkage bearings, or rear shock absorber(s) / damper(s) pivots were disassembled, cleaned, inspected and greased, it's probably safe to assume that the swingarm and linkage bearings, as well as the shock absorber(s) / damper(s) pivots are likely in need of service.
If you recently bought a used dirt bike, it's probably safe to assume that the swingarm as well as the linkage bearings and / or shock absorber(s) / damper(s) pivots all need servicing.
We cover this in detail below but don't be surprised if you see parts falling out in a pile of red dust upon disassembly.
In addition to the above mentioned signs of the swingarm and linkage bearings needing service, and / or shock pivots being in need of service, Another good indicator is while the dirt bike is on a stand, with the rear wheel off the ground, there should be NO movement (slop) up and down, nor from side to side.
A simple and effective way to check for wear within the rear suspension is with the motorcycle on a stand and the rear wheel hanging. Grab the rear wheel or swingarm by hand and lift upward slightly, as well as pushing and pulling from side to side.
Note: When lifting on the swingarm, you are only wanting to lift with enough pressure to feel for any slop in any bearings, and not lift the swingarm in a way that the shock begins to compress, or the entire motorcycle comes up off the stand.
If there is enough wear that it's noticeable while doing this, the swingarm and linkage bearings and / or shock pivots are definitely in need of service and should likely be replaced as well, since cleaning and lubricating alone will not take this slop out, and pretty much everything you need to know is detailed below.
If you're fixin' to go for it and get your rear suspension dialed in, and it's been a while since any of the rear suspension has been disassembled for a good cleaning, inspection and lube job, or if you've just bought a used dirt bike and you're not sure when the last time was that it was serviced (if ever), then you may (likely) find that most of the pivot bolts are seized and do not come out easily, which is necessary to enable disassembly of the swingarm, linkage and rear shock absorber(s) / damper(s) from the motorcycle.
Before you get too far ahead of yourself, it's also a good idea to get a factory service manual specific to the motorcycle you're working on, as you'll be needing this during reassembly for torque specs, and setting bearing depths, as well as other info throughout your days of working on the dirt bike.
If there is any "beating" required, make sure to use some good, quality penetrating oil, A Brass Punch and a brass hammer to help move the bolt / pivot shaft through the swingarm and linkage bearings races / collars or shock absorber(s) / damper(s) just don't keep beating the shaft / bolt through the swingarm and linkage bearings in one direction only. You'll need to "work" the shaft / bolt back and forth from both directions, gradually working it loose and out.
If you get the idea to fire up the torch and heat things, that may not be such a good idea. When working on the rear suspension / swingarm and linkage bearings, as well as the rear shock absorber / damper (which is gas charged), if the pivots are seized and not moving, heat is not going to help much, as the heat often cannot be directed where it needs to be, which is directly at the inner collar / race that the pivot bolt passes through and is seized to. Bottom line is applying heat to the swingarm or linkage is not going to do much good.
Once you have everything apart, it's important to clean all the parts and inspect everything before getting out the grease and reassembling parts, so the following are a few things to look for:
On the linkage or shock(s)... When you're cleaning the linkage bearings or shock bearings, be sure to pay close attention so you don't lose any of the needles that make up these bearings, as there are a lot of them and they will all come out during cleaning.
Note: Shock absorber bearing / pivot kits frequently come with a top spherical, or needle bearing, as well as a bearing or bushing that goes into the part that the shock absorber bottom mount attaches to. This is generally the swingarm on linkless setups, or the rocker on linkage style setups.
Additionally, If things have been going smoothly with disassembly, and even if you were not aware of any slop in the rear suspension, but after cleaning the parts and inspecting them, if you notice any "Blueing", "Pitting", "Notching", "Grooving", Corrosion or other noticeable wear of the needle bearings, collars, bushings or any of the other parts that make up the rear suspension's pivoting, as well as if you notice any missing needles from a bearing during reassembly, it is highly recommended that you replace these parts while you have it all apart, this way you will be able to obtain the best performance from your rear suspension and have a sweet handling ride.
If you've determined it's time to replace some or all of the swingarm and linkage bearings, or shock absorber / damper pivots in the rear suspension for obvious or not so obvious reasons, here's a few things to know that should help...
First grab the new parts (bearings) and apply a light coating of an "Anti-Seize" compound to the outer shell / race of the bearings where they will be in contact with the swingarm, linkage or shock absorber(s) / damper(s) and then throw 'em in the freezer for a few hours (overnight is better), then we'll continue.
If you don't have any "Anti-Seize", you'll be needing it in future uses as well, so now is a good time to get some and it is available at most auto parts stores, but be sure to get the anti-seize in a jar with an applicator brush.
Removal of either swingarm and linkage bearings or shock absorber / damper pivots needs to be done by steady pressing action. If you don't have access to a press, all is not lost as this can be done with a vise and sockets, (although a press is the preferred method).
Below, you'll find instructions for using a vise and sockets to remove and install the swingarm and linkage bearings, as this is what most people have access to, although before continuing, it is recommended that you have "Soft Jaw Inserts" in the vise, so as to not damage expensive suspension pieces with the jaws of a vise, which are commonly sharp and of a very hard material that easily damages aluminium or other suspension pieces and tools.
If you need soft jaw inserts for your vise in a hurry, and don't want to, or have time to wait for magnetic inserts to show up in the mail, nor can you find any locally, you can head down to the hardware store and pick up a length of 1" aluminium angle material and cut 2 pieces the width of your vise jaws which you'll find will work very effectively.
If you're performing the very common task of removing and reinstalling swingarm and linkage bearings in any of the rear suspension components, here's how to go about it with a vise and common sockets:
Once the old bearings have been removed from the part you're working with, whether this be the swingarm itself, the linkage, or the shock absorber(s) / damper(s) it's very important that you thoroughly clean all the parts you'll be reusing, and inspect the bore that the bearings will be reinstalled into.
It's important to clean all the parts which may be reused and thoroughly inspect the bores, looking carefully for any nicks, gouges, burs or raised areas in the aluminium, steel or unobtainium that may have been caused during removal of the old bearing(s). During your inspection, you'll likely find that using your finger to feel for any irregularities is the best way to ensure a smooth bore for the bearing to be reinstalled to.
If there is any damage / irregularities noticed in the bores where the bearings are going to be installed, it's important to address this before re-installation of a new bearing, and this can be done best by using a light grit sandpaper held on your finger, but when removing any burs or the like, it's important to use care so as to not remove any more material than is necessary to restore a smooth bore, then go over the bore once again with scotch-brite to achieve a nice smooth hole for the bearing to fit into.
Provided that all your parts are clean and free of any burs or other types of irregularities in the bore where the bearings are to be installed, and your new bearings have been in the freezer for a while, you'll want to make sure you have a clean work area, then take the bearings from the freezer one at a time and reinstall them into the swingarm, linkage, or shock absorber(s) / damper(s), being certain to install each bearing to the same depth as it was before removal, or as specified in a factory service manual specific to the motorcycle you are working on, then installing any circlips as required before moving on to the next bearing, repeating this procedure until all the bearings have been reinstalled and secured.
Considering that there is little to no grease installed from the manufacturer in replacement swingarm and linkage bearings, as well as shock absorber / damper pivot bearings (whether OEM or Aftermarket) you will need to apply a good, high quality, high performance grease such as Bel-Ray's Waterproof Grease to the bearings before reassembly of the pivot collars and seals, or assembly of assembled components to the motorcycle, all of which is discussed below.
If you have just reinstalled new bearings throughout, or you cleaned your existing bearings, and you're now ready to put it all back together, here's how to lubricate the bearings for maximum lubricity.
If you're working with new, freshly installed bearings...
If you just finished installing new bearings with the steps detailed above, before you begin installing the collars and seals and reassembling everything, it is highly recommended that you slather some good, high quality, high performance grease such as Bel-Ray's Waterproof Grease into the bearings before assembly, then assemble everything, torquing all bolts to the manufacturers recommendations as can be found in a factory service manual specific to the motorcycle you are working on.
For those who are working with pre existing bearings...
If you're only in this for some routine preventative maintenance and you are working with bearings that have just been cleaned, and are in good shape, you likely have a pile of needles laid out on a clean rag and are ready to get this whole mess put back together.
With everything clean and either inspected or replaced, go ahead and apply a nice & thick layer of high performance grease to the bearings in the swingarm as these are generally caged bearings and all the needles remain intact during cleaning (or should anyways).
Once the swingarm pivot bearings have been greased, the remainder of the swingarm pieces such as thrust washers and thrust bearings, as well as the inner collars and outer seals can be reinstalled to the swingarm as illustrated in a factory service manual specific to the motorcycle being serviced.
After reassembling all the pieces to the swingarm pivot, you'll need to reinstall the loose needles back into their respective bearing's outer races so here's some tips that'll make this easier on you.
Reinstalling the needles back into their races is best done by applying a thick coating of grease to the inner circumference of each outer bearing race, then reinstall the individual needles to each race, being certain there are no gaps remaining between needles before installing any collars through the middle, finishing this by reinstalling any seals or outer collars while being certain to pay attention to the direction of any collars or seals and reassembling the shock linkage, then reinstall the assembled linkage to the swingarm and lastly installing this assembly to the motorcycle and install the rear shock absorber(s) / damper(s) to the motorcycle, torquing everything per the manufacturers recommendations as can be found in a factory service manual specific to the motorcycle you are working on, then completing the job by reassembling any other parts that were removed.
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