how to check swing arm's linkage (easy way)

Street bikes do not usually have problems with the swing arm's linkage but dirt bikes/ off roaders, duals, enduro, and especially MX and trials racers are prone to have problems with the linkage. Dirt is the no.1 enemy and it will enter the seals and damage the linkage bearings. A direct hit on the linkage (rocks, logs, etc can cause much damage to the bearings and the arms also. Street legal bikes have better seals than racer models because it is a must to regularly service/repair full racer models and everybody knows that... Using pressurized steam jets to wash the linkage is really not a very good idea because water will cause the linkage bearings to rust. Driving in deep water is also not a very good thing to do if you will not dismantle and do a full grease up on the linkage bearings. That is the reason why I do not like riding in deep waters. 

How to check: Lift up the rear tire (use a jack and best if the rear tire is removed), hold the swingarm and move it upwards, downwards, and sideways. It should not shake. If you have doubts, dismantle the shock absorber/spring and test the swing arm again. A small bit of shake is OK and it wont kill you but if the shaking is too much, you must replace the bearings.

*** to replace the swingarms linkage bearings (needle bearings), remove the linkage, pry the oil/dust deals, push the bearing out by using a press OR you can use a stationary vise and use wood. Look for a socket that has the nearest size to the needle bearings and pump it out by compressing the vise (just be imaginative and this will work). Fit new bearings and seals. 

*** so you don't have the parts... remove the linkage, BUT do not pry the seals. Check for damages. If there is too much rust check if the needle bearings will move and if not, dip the linkange in a pan of kerosene and go for lunch... Now check the needle bearings again and try to move the needles GRADUALLY and ONE AT A TIME. WD40, CRC or any deep penetrating oil will help. Be very careful not to damage the seals. If the bearing is now moving and you've got most of the rust, dirt, oil, crap out from the bearing, dry it and put grease (the more the merrier). Assemble the parts together and check/shake the swingarm again. There will be a bit of shake but who can complain... change the bearings if you have the parts at hand but this will do for now. 

*** Some swingarms will not shake and may look OK because there is just to much rust build-up in the linkage and the movement will be hard. Some bikers will only change the shocks/springs but will not check the swingarm's condition, naturally the performance of the "new" aftermarket spring/shock will not be used 100% because of the rusty linkage bearings that fcks up the swingarm's movement. It is like wearing brand new shoes but without washing the feet...