Originally posted by afm
Are you sure it is the two needle carb??? That is a very old Sirio carb which had a lot of problems to tune it correctly, and that is why they changed to the 3 needle carbs of late Sirios.
Any way, Sirio recommends the following base settings:
HSN needle 5.5 turns out
LSN needle 3.75 turns out (should be flush with the end of the slide body)
Mid Range Needle flush with carb body, than 1 turn out
Glow Plug Novarossi C7TGF
Sirios need a lot of fuel, they don't perform well if you lean them to much.
If you really have that 2 needle carb, better be thinking on changing it for a Nova based carb, or the new Sirio carb.
Hope this helps
AFM
Yes, I have the 2 needle carb.
When I first bought the engine it had the 3 needle carb.
That carb was giving me problems.
So I sent it to Trinity, and they sent me the 2 needle carb.
Both carbs suck.
This has been the only engine I can't tune.
Every time I try to go below 5 1/4 turns, everything goes out of wack.
So I leave it at 5 1/4.
That's why I want to know what everyone else is running,
I just want to see if I could get more power out of it.