Hi.....
Glad I was of some help, and thank you for the compliment.
For carb and needle setting, go here
http://www.jettengineering.com/tech/techcarb.html
Set the idle needle flush with the end of the throttle arm nut (for starters).
Piston/sleeve assembly and needle valve change out can be done on your end. They are not difficult if you have some experience with engine assembly. That is up to you, and will depend on whether there are other concerns with the engine. If you wish to send the engine in for service, we can inspect and repair the engine, and return it to like-new performance.
Service may be obtained from:
Jett Engineering Inc.
6110 Milwee Suite J
Houston, Tx. 77092
USA
Bob