Could also be a crack in the pipe at a flange.  It's not the easiest thing to
see since it doesn't move much when it does break there.  I've had them do
this on the front pipe at the #1 cylinder and the rear pipe at the Y pipe.

SSG Brad Spear
'72 Westy
'87 Syncro GL

In a message dated 97-09-07 19:52:10 EDT, WaywrdCyc@AOL.COM (Mike Yozell)
writes:

<< Scott
 Look carefully at the pipes . All the way from both sides of each head to
the
 junction  of the collector
 Igot a 2 or 3 mm hole in the pipe on mine .Loud as all get out !!!
 Covered it with a piece of soda can and a hose clamp
 6 months and no failure

 mike 85 westy >>