Re: Arc Welding on engine muffler area?
I wouldn't weld anything directly to the engine... get yourself some self locking nuts, not the ones with the plastic inserts, but the all metal self locking nuts and problem solved.
Now if you're just trying to weld the muffler to the pipe or something like that, it's not easy as the metal is very thin but brazing it will hold up just fine, I've brazed pipes together on my Buell with no issues before.
If you're trying to stick weld it, you'll need to use a 1/16" rod but that may even be too much as the amperage will need to be set really low and the rod will tend to stick to the metal before getting a good arc started, but if you turn it up enough to not stick to the metal you'll risk blowing holes in it. You might get away with oxy acetlyne gas welding it or Mig/Tig but beware of teh really thin and cheap metal these are made of.