Originally posted by Exe
well.. i bough 12 ROssi blax pixy outlaw 5 port , but i can get
how to tune ir properly...
when i look at the pictures of the carbs in tech tips, i cannot
understand which needle is which...
ok, here it goes, i have high speed needle, then as i understand
mid-range needle which is located next to the balck needle which physically closes or opens carb - low speed needle if i'm correct,
and on the other side of the carb, i have another needle which is in the middle of the ring, to which i connect throttle linkage. what is this needle ? can someone tell me what are the factory settings for all these needles and how to tune this engine properly?
Taken from Trinity's web site, importers for Rossi engines:
All carburetors are factory set on a flow bench. For this reason it is recommended that you count the number of turns on the low and high end needles before you use the engine. All carbs are not the same, but are set to flow the same amount of air and fuel. Up to a one half turn difference can be had on factory carburetor settings on each needle. A two micron difference in the needle taper can make the setting up to 1/2 turn different from another carb. It is also not recommended not to adjust the mid-range needle setting on your Picco, Sirio or Rossi until you are completely comfortable with carburetor adjustment.
How big is a micron? There are 25,400 microns in one inch. This dot (.) is approximately 1/64 of an inch wide and equals 615 microns. It doesn't take much to off set a needle setting.
Rossi Engines (General Carb Settings)
Low End: 4-3/4 turns out
High End:3 turns out
Midrange: Flush with carb body
Looking your carb from the top:
What is the "Top End" needle?
The "Top End" needle is the large needle valve on top of the carb that adjusts how much fuel is delivered to the engine from half throttle to full throttle.
What is the "Bottom End or Low end" needle?
This needle is to your right, at the end to which you attach your throttle linkage, and adjusts how much fuel the motor gets at idle and at the first crack of the throttle.
What is the "Mid Range needle"?
As its name says it, it adjusts how much fuel you get between high and low speed, but as they say this is factory set and shouldn't be taouched unless it has allready been messed up. It is located to your left under the high speed needle.
What is the "Idle needle" '
As its name says it, it adjusts engine idle, and is located near the engine crankcase.
Hope this helps