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

Definitely looks bulletproof now. Dang good job. Even though I don't haul a sidecar, I may do that anyway. I already have the square tubing, just need a welder.

Hi Phelonius, I'm checking out side-cars going to fit one on but not sure of the fixing points would it be suitable to fix one of the anchors to the pilon foot peg, just wondering if it would stress the swinging arm cheers,,kenny

Got you ,Aye when I had a right look at it it would be a bit nuts to connect it there,,cheers and ta

Okay, you guys have raised a few questions.  First NEVER attatch a sidecar mount to a swingarm.
Second, as for potential cracks due to verticle welds, The theory may have something to watch for but the original has lasted more than 20,000 miles without a problem.  
The one worked on in the photos is the second one I have done and it was new when I started. Absolutely no cracks to repair first. I took my time and really went slow on this one.
The photos below show the finished product. Note that I taped off the graduation marks where the axle goes through. This was so that paint buildup would not make the marks difficult to see. In fact, this morning I sprayed light color paint on the marks and wiped it off with a paper towel. This left the paint down in the crevices to be more readily visible.



Phelonius

srinath wrote on 05/12/09 at 13:10:12:

gotta realise, this bike was probably never engineered with the idea of adding a sidehack... as there's probably a collective million plus miles on savage-back found in this forum, and this is the only mention of the problem i've seen, id be inclined to believe the arm is well made for the intended purpose, just with a minimum safety factor.... Phelonius' original bad arm may have been due to a fab defect in that particular arm..... save those engineer beat-downs for the cats that designed the cam chain tensioning scheme...lol

Hey Phel -
I actually didn't notice that you were talking about a sidecar rig.
Cool.
Srinath.

Phelonius wrote on 05/13/09 at 14:44:55:

absolutely right abought the pegs.... and if they HAD to do it, they shuld have at least added a reinforcing sleeve(like the "frame nuts" on older bicycles, those old ones were pointed for a reason)... honestly wish i could take credit for the points idea, but i learned it the hard way almost 3 decades ago... i patched a cracked trailer frame about 5 times before the guy across the alley asked me if id like to fix it right once, or was it a hobby?.....gotta love new yorkers... he explained about the stress riser, and told me to cut my patch football shaped... needed a new hobby after that one went on....lol