This link is to the download of the manual with the Tec jet chart and part numbers. to find them for sale (e-bay etc.) you really need the part number. stock 6.5 tec jet is a 141. if you mod, you'll likely need to change it. i installed a Tec adjustable needle in place of a fixed jet so i can change it when needed just but turning it in or out.
http://www.barrettsmallengine.com/te...partslist.html
This link is to the page with the various tec models and a basic Tec service manual download ...
http://www.smallenginesuppliers.com/...ine-specs.html