It's really easy. just wind it round the tube tightly on the first loop if it's oval (can't remember them 70's, but I think it's round) If it's round just keep winding it until it's snugg but not too much. Use care when inserting the assy' as you want to first of all line up the tubes inside and two don't break the new packing. Also 2 stroke packing will last very little and will break appart (you will notice it coming out of the tail pipe) Just use 4 stroke packing, it's very easy to find these days. The sound and power will be improved too.
TORKER.
THOSE WHO SAY IT CANNOT BE DONE, SHOULD NOT GET IN THE WAY OF THOSE BUSY DOING IT...