john1652 wrote on 12/31/69 at 16:00:12: 
does anybody have a dyna muffler that doesn't leak. I have read som very long involved processes to get them to stop leaking , I think I even read where sombody welded them to the head pipe. well just wondering john
Yup, I did finally just have my neighbor TIG weld it for me. I could have just borrowed one of his MIG machines and done an adequate job, but the TIG weld is very pretty. If I didn't already have such a nice heat shield to cover it, the weld was pretty enough to leave exposed!
Oh... no it doesn't leak a bit. Yes if I want to change mufflers I'll have to buy another header pipe, or use the cutting wheel on my die grinder to cut the current muffler off at the weld; then smooth the area down. Now that I've done it this way, I doubt I'll bother fighting with any other method again.
Tips: Get the muffler you want; Get it positioned exactly where you want it; clamp it together TIGHT with a heavy duty u-bolt clamp so it CAN'T move!!! Remove the header pipe/muffler and take the whole assembly to the weld bench. CAUTION: Be careful not to let the welder's ground arc from the table to any surface that shows when mounted on the bike... We mounted the whole pipe/muffler in a vice via the muffler's mounting bracket, and that grounded it through his welding table. If you just roll it around on a table while welding on it, you'll end up with nasty grounding arcs all over your nice new muffler.