Page 208 - Sudco Int'l Vol.37.pdf
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INTAGE
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NTAKE
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NGINE
S
USPENSION
C
ONTROL
E
LECTRICAL
C
HEMICAL
T
OOLS
W
ATERCRAFT
Jet Needles
Jet Needle #4 Series
Competition Racing
Overall
Leaner
1
#4D8
#4P3
#4P3
2
#4DH7
#4D8
#4D8
3
#4DG6
#4D3
#4D3
4
#4P3
#4F10
#4DG6
5
#4D3
#4DG6
#4DH7
6
#4F6
#4F6
#4F10
7
#4F10
#4DH7
#4F6
8
#4F15
#4F15
#4F15
9
#4E14
#4E1
#4E1
10 #4J13
#4L13
#4L13
11 #4L6
#4J11
#4J13
12 #4L13
#4J13
#4J11
Richer
13 #4L11
#4L6
#4L6
Jet Needle #5 Series (A)
Competition Racing
Overall
Leaner
1
#5D6
#5C4
#5C4
2
#5D120
#5D6
#5D6
3
#5C4
#5D5
#5D5
4
#5EJ13
#5D120
#5D120
5
#5J9
#5D1
#5F18
6
#5F18
#5F18
#5D1
7
#5DP7
#5F16
#5EJ13
8
#5FL14
#5FJ9
#5F3
9
#5F3
#5F3
#5EH7
10 #5EH7
#5EJ13
#5FJ9
11 #5FL
#5EH7
#5DP
12 #5D5
#5DH21
#5FL14
13 #5E13
#5FL14
#5FL7
14 #5L1
#5FL7
#5E13
15 #5J6
#5E13
#5F16
16 #5D1
#5DP7
#5DH21
17 #5F9
#5J9
#5J9
18 #5F16
#5J6
#5J6
19 #5DH21
#5L1
#5L1
Richer
20 #5F12
#5F12
#5F12
Jet Needle #5 Series (B)
Competition Racing
Overall
Leaner
1
#5EP8
#5DP2
#5DP2
2
#5EJ11
#5DL13
#5DL13
3
#5EL9
#5EJ11
#5EJ11
4
#5EL9
#5EJ11
#5EJ11
5
#514
#5EP8
#5EP8
6
#5DL13
#5FL11
#5FL11
Richer
7
#5DP2
#514
#514
Note:
The following listing of needles are simply the average
performance of a needle between 1/4 and 3/4 throttle opening.
Needles are constructed such that a given point on a needle,
(for example, at 3/4 throttle opening), the needle may be found
to perform richer at this given point when compared to the
same given point on another needle, but according the the
average performance chart, the needle should perform leaner.
For example:
Average Performance Chart
Leaner
Richer
At
D-5 (A)
, the taper diameter is
1.915
, at
D-5 (b)
, the taper is
2.040
; the taper diameter at
D-5 (A)
is smaller than
D-5 (B)
.
At this given point of throttle opening
(3/4)
, needle
#6DH4
will
run slightly richer than
#6FJ6
, but the average performance will
still be that
#6DH4
will be a leaner needle because it will
perform leaner at more given points than a
#6FJ6.
Consequently, if you are concentrating on a specific throttle
opening for competition use, be certain to check the taper
diameter at that point of throttle opening.
For a more detailed and comprehensive explanation of the
various needles as to their taper diameters at given points,
see
NEEDLE TAPER DIAMETER DIMENSION CHARTS.
THE QUICK REFERENCE CHART FOR NEEDLE
SELECTION
was prepared by measuring the needles as to their diameter at
given points. Given points are 10mm apart from each other.
By computing the different measurements and arranging them
in order of taper thickness or thinness, three categories for
application of needles were determined.
Category l - Competition.
For example, motocross racing and desert racing where
mid-range throttle operation is vital.
Category ll - Racing.
For example, Road racing, where 3/4 to full throttle
operation is vital.
Category lll - Overall.
For example, Street riding,
where the full range of throttle operation is required.
Quick Reference Chart for Needle Selection
(average Performance Chart)
