Oh GOD No! If it was steel, I'd be all over it. Been welding since I was a sophmore in high school (ag class). But aluminum? With me on top of and relying ON it? Hell No! LOL, no no no no no. There's a company in town that is just for welding stuff like farm equipment and whatnot. No, THEY'LL be doing it, NOT I! LOL
If your welding the swingarm, and have never welded aluminum I would highly recommend letting the shop do it. If the temp isn't just right it could end very badly. Remember the 2007 GSXR1000 recall on the frames splitting apart. The temp was too cold and didn't actually fuse the aluminum, the weld just sat ontop, but it looked great on the outside.
To each his own, but I have welded all types of steel for more than 10 years and I would not weld my own aluminum swing arm and I have access to a aluminum welder.