I found a site that carries all the beta manuals from the TR34R to the new evos from beta it self. all the techno years are listed as well. In PDF. As far as your fuel mixture goes i own a 94 techno 250 and run a 100:1 mixture in it. I mix 6.5 ounces of oil to 5 gallons of gas in other words. It runs great at that mixture here in colorado and i have never had a problem with it.
Beta Parts and Manuals
http://www.trialsport.com.au/beta/documents.htm