Way back about 20,000 miles ago and 16 months, I found a crack in my swing arm that ran about 3/4 of the circumference. After I got over the hair standing on end, I realized that it was because of an inherent weakness of the Savage swingarm. Suzuki in all it's wisdom, mounted a footpeg in the middle of the swingarm. They did not even complete the weld job on it. Since the arm has been indented on the back side further weakens it.
Now for all you two wheelers, Ignore the rest of this thread. For those of you who tug sidecars, this is of the utmost importance if you wish to stay alive.
Imaginge if you will, a cracked swingarm breaking off at 55 mph with a log truck right behind you, Or maybe while negotiating a mountain curve with a thousand foot drop below. Even on level pavement it could kill you as it would most assuradly cause a violent rollover.
Okay, so here is the cure. remove the swingarm from thew bike. obtain some 1and 1/2" square steel tubing. Cut two 12 "lengths.
Trace the curve of the swingarm onto the tubing and slice it lengthwise with a bandsaw. Make a couple of slits in each end to accomodsate a taper. With a portable disc grinder, make the curve of the steel match the curve of the arm. Sand all the paint off the arm in the areas to be welded. Cut a piece of pipe to fit between the arms and put the axle through the arms and the pipe and nut it snug. This is to help prevent warp. Hold the steel in place with a C- clamp and begin to weld. NOTE, weld inshort beads no longer than 1 and 1/2" long begining at the center and working towards the ends. Have both pieces clamped and allow the first bead to cool before running the second.
You can do one side for a bead then the other side for a bead, then turn it over and do a bead on each side, then allow it to cool before welding any more. Sure, this is a slow process but unless you want the swingarm to warp terribly from heating and cooling, it is a must.
When it is all welded, grind off any excess or unsightly stuff, clean it and paint it.
When done, it will be far stronger than stock and fully capable of any sidecar stresses a Savage is likely to impart to it.
Notice in the last photo with the primer paint on it, The swing arm is boxed on the inside too, with lesser boxes.
Phelonius