Now some of you might be thinking 'Hmmm, and exploded view of a Sporty - it must have gone BANG in a big way'. But what I am actually after is if anyone has, or knows where I can obtain, an exploded diagram of how a '76 (or thereabouts) Sport goes together. In all, the hard work is hard, but there's some washers and such like that might or might not go in particular places, and it would be nice to get it right. Any thoughts on this gratefully received.

An appropriated parts manual would do the job.
Google is your friend here.

 i have one inside my head just ask,  no worries on early sporties

Try www.shopronniesharleydavidson.com, lists all illustrated parts breakdown.

 if you have any ques on castiron sporties just ask  no worries i don't have too look in a book 

 There is a good one here,,

http://youtu.be/ORR-MmnEFak