[Spridgets] Tuning SU Carbs

[Timothy H. Collins]

My reference book: "Tuning S.U. Carburetters, 3rd ed. Speedsport.

pg. 62 Spring-loaded Jet Needles

 From the book. . .
The shoulder of the needle (3) abuts a protusion (sic) formed on the 
face of the needle guide (5), so that when held in place by spring 
(4) the needle adopts a biased position (7) in the fuel jet orifice. 
The direction of the bias is either to the inlet, or the outlet side 
of the carburetter as indicated by etched location marks on needle 
guide and piston.
_________________
I find the etched line on the needle guide. The needle guide is the 
part that the set screw in the piston clamps against to hold the 
needle in place.
I don't find a corresponding etched line anywhere else, but I'm not 
sure where to look. Where on the piston is the alignment mark? Does 
all this matter much?

On spring needle carbs, the needle is biased (rubs on the side of 
the) the JET and is not centered as with a fixed needle.


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