Author: Rocky from Bad Boy Bikes

When you find your chain falling off constantly and your trying and trying to tighten it and its just not working. Chances are your swing arm bearings need replacing. Easy well to tell is to loosen up the chain and then raise the rear of the Atv so both rear tires are off the ground and simply move the tires side to side and watch at the junction point where the swing asssembly is bolted to the frame. You will see a lot of movement and slop there. Normally on the sprocket side as thats where the tourque is delivered.  Many things cause this issue like overloading the weight capacity, tightneing the chain to much etc.

 the rear swing arm bushings look like this

These are located inside the main tube of the swing arm that bolts to the frame pic below

So if you have more than 1/8 of an inch play in your swingarm then this is what you need to do. I know Gio supplies a free set of spares with the 110cc mini hummer. You can also have them fabricated out of brass for a very low cost  (pic below of my brass ones)(about 30-65.00) these brass ones will last a lifetime and will outlast most riders in life expectancy.

Swing arm removal. While the unit is still raised with the rear tires off the ground, First unbolt the bolt/nut on the lower end of the rear shock. Next take off the 2 rear brake caliper bolts using a 10mm wrench or socket. Next remove the wheels and tires and the axle spacers and also slide the sprocket off.  Lastly simply loosen and remove the main swing arm bolt that holds the whole assembly to the main frame. Your swing arm is now free. Move it aside or place in a vice or on bench if you have one. Next take a look inside the main tube of the swing arm you will see how worn out the bushings are if they are even there at all like this one in the pic below as you can see only the outer and inner sleeves are left!

 Now we need to get the old bushings out. This can be done by using a flat head screwdriver and by putting on the outer sleeve and pounding it with a hammer, it will cut it and you will be able to lift and work it around until you can get it out. It is a pain but really doesnt take that long about 10 minutes for 1 side.

After you have 1 side out you can use a one size smaller socket to pound out the other side. You can also make a bushing press for about 3 dollars. See this post for one of those. Very great tool at pulling and pressing them in.

url for this is here  http://www.thumpertalk.com/forum/showthread.php?t=433397

Now that this step is complete you simply have to pound or press in your new bushing. If you opted to get some brass ones made up you can easily lube them and pound ONE SIDE in. Once you have 1 side in you MUST put the long spacer in before installing the last bushing. This spacer keeps the bushings in place at the correct distance apart. Simply put the bolt through the installed spacer and put the spacer over the bolt. Leave this attached as to keep the spacer lined up perfectly until there is some stress on the bushings to hold it. Now using your 3 dollar press simply crank it in its resting place. Then pull the main bolt and line up the swing arm to the frame. Then simply put the bolt back through and tighten the nut. Install the brake caliper, and shock. Install the sprocket, and wheel spacers and lastly the tires. Then be sure to take advantage of that new grease nipple and fill it up with grease. Now simply tighten the chain to one half inch slack or deflection in the middle of the run. The chain should mover up or down about ½ inch. Do not over tighten chain as its the number 1 cause of bearing and bushing failure and early wear out hands down! Cheers and get out there and ride.