I found an excellent book available online at no cost.
Two-Stroke Performance Tuning by A. Graham Bell
ISBN # 978 1 85960 619 3
Although the first printing was way back in 1983 there is alot of good info in this gem.
I paid $40.00 + shipping for this last year.
The web site is called scribd, it is a hosting site for pdf's and the like.
There is no cost to sign up, the Idea is to share what you have and use what you need.
This should get you to the book.
http://www.scribd.com/doc/8568237/Performance-Tuning-Graham-Bell To the top right, next to the document there is a tab that says download free PDF.
If this doesn't work you may have to sign up first.
This is the Home page:
http://www.scribd.com/ Tuck\o/