These settings are base settings for all sirio non sti 21 engines low end needle 5 and 1/2 turns from closed main or high speed needle 6 and 1/2 turns from closed and mid range is flush and then 1/2 a turn out. All these settings will get the engine running they are not factory settings more of a general starting setting if your carby gets all out of wack they should be a ritch carby setting as well. If not ritchen the main needle antill you get a ritch carby setting and then begin to retune your engine rembering that your engine will not hold a consistant tune antill it is at normal running temp around 90 to 120 dec C at those running temps your engine can be tuned corectly and it will hold a tune better as well. Hope that gives you some ware to start from. Also with the Sirio pr pro or pr pro evo2 and sti evo2 engines always use a number 7 turbo sirio glow plug with 25% nitro if you run higher nitro or in a very hot climet say air temps above 40 deg c you may need to go to a sirio 8t plug. Alway use a sirio or now a Rb zenon or matrix exhaust system for max paformance on and off road. Most improtant of all you must use a quality fuel that is vital to long engine life regardless of brand. Best Regards Jeremy.