Mikuni Needle Information

Jet Effectiveness

A=Most effective

C=Little influence

B=Partly effective

D=No influence

 

Slide Opening

 1/8  1/4  3/8  1/2  3/4 WOT

Cutaway

 A A B B C D

Pilot jet

 A A B C D D

Airscrew

 A A B C D D

Needle Jet 

B A A C C D

Needle

 C B A A B C

Needle position

 B B A A B D

Main jet

 D D C C B A

Power Jet

 D D D D C A

 

Needle Jet Sizes   Needle Jet Application Chart

Size

Dia (mm)

Size

Dia (mm)

 

Series No

Type

Main Jet

Size

Carb Type

N-0

2.550

Q-2

2.710

 

159

P

Hex

O-0 R-8

30-36mm spigot

N-2

2.560

Q-4

2.720

 

166

P

Hex

O-0 R-8

38mm spigot

N-4

2.570

Q-5

2.725

 

 169 P   N-0 Q-8 28-38mm small

N-5

2.575

Q-6

2.730

 

171

P

Hex

O-0 Q-8

30mm flange

N-6

2.580

Q-8

2.740

 

 172

P

   N-0 Q-8 28mm flange

N-8

2.590

R-0

2.750

 

 175

B

   N-0 Q-8 28mm spigot

O-0

2.600

R-2

2.760

 

176

B

Hex

N-0 Q-8

30-36mm spigot

O-2

2.610

R-4

2.770

 

 182

P

   N-0 Q-8 26mm spigot

O-4

2.620

R-5

2.775

 

183

B

Hex

N-0 Q-8

38mm spigot

O-5

2.625

R-6

2.780

 

188

P

Hex

O-0 Q-8

32mm flange

O-6

2.630

R-8

2.790

 

 192

P

   N-0 Q-8 26mm flange

O-8

2.640

Z-0

3.150

 

193

P

Hex

N-0 Q-8

24mm flange

P-0

2.650

Z-5

3.175

 

196

P

Round

O-0 Q-8

30-36mm spigot

P-2

2.660

AA-0

3.200

 

205

P

Hex

O-0 Q-8

34mm flange

P-4

2.670

AA-5

3.225

  

211

P

Hex

N-0 Q-8

Kaw KR250 350 750

P-5

2.675

BB-0

3.250

  

224

P

Hex

Z-0 CC-5

40-44mm spigot

P-6

2.680

BB-5

3.275

   235

P

  

O-0 Q-8

30mm flange

P-8

2.690

CC-0

3.300

   247

P

   P&Q Yam250 YZ400 IT400

Q-0

2.700

CC-5

3.325

  

249

P

Hex

N-0 Q-8

24-28mm spigot
          258

B

   O&P Yam Kaw Suz
          261

B

   N-0 Q-8 VM29 VM33
          389

P

   O-0 R-8 TM32 34 36 38 41
          499

B

   P-2 Q-4 TM33
         

P=Primary, mainly used in 2-S piston inlet engine
         

B=Bleed, mainly used in 4-S & 2-S rotary and reed valve engines

 

Needle Tapers
Letter Taper   Letter Taper
A 0º 15'   N 3º 30'
B 0º 30'   O 3º 45'
C 0º 45'   P 4º 00'
D 1º 00'   Q 4º 15'
E 1º 15'   R 4º 30'
F 1º 30'   S 4º 45'
G 1º 45'   T 5º 00'
H 2º 00'   U 5º 15'
I 2º 15'   V 5º 30'
J 2º 30'   W 5º 45'
K 2º 45'   X 6º 00'
L 3º 00'   Y 6º 15'
M 3º 15'   Z 6º 30'

 

Needle Dimensions

X = The total length of the needle
Y = The measurement from the top of the needle to where the taper starts
 Z= The dimension in mm from the top of the needle to the pronounced taper point.
10-20 etc= The diameter of the needle measured from the top at 10 - 20 etc mm

4 Series Needles 26 spigot, and 22 & 24 flange carburetors
Needle X Y Z 10 20 30 40 50 60 70

4D3

 50.3 25.3   2.511 2.511 2.421 2.253 2.100    

4D8

 50.3 22.8   2.519 2.519 2.381 2.211 2.000    

4DG6

 50.3 24.0   2.518 2.518 2.405 2.119 1.850    

4DG8

 50.3 24.0   2.518 2.518 2.405 2.118 1.850    

4DH7

 50.3 23.0 2.518 2.518 2.386 2.098 1.790    

4E1

 50.3 28.0 2.515 2.515 2.345 2.127 1.924    

4F6

 50.5 25.3 2.514 2.514 2.406 2.145 1.876    

4F10

 50.2 24.5 2.513 2.513 2.385 2.135 1.877    

4F15

 50.3 26.5 2.512 2.512 2.400 2.120 1.881    

4J6

 50.3 24.2 2.513 2.513 2.233 1.827 1.472    

4J11

 41.5 21.3 2.512 2.506 2.188 1.776    

4J13

 50.2 24.0 2.513 2.513 2.230 1.800 1.400    

4L6

 50.3 24.5 2.515 2.515 2.178 1.660 1.190    

4L13

 45.1 25.0 2.518 2.516 2.339 1.842    

4P3

 50.5 25.0   2.510 2.506 2.436 2.284 2.122    
2.311
5 Series Needles 26-32 spigot, and 28-34 flange carburetors
Needle X Y  Z 10 20 30 40 50 60 70

5C4

 55.1 24.0   2.516 2.516 2.448 2.310 2.179    

5D5

 57.6 30.0   2.513 2.513 2.510 2.366 2.205    

5D6

 59.3 27.5   2.515 2.515 2.460 2.290 2.120    

5DH21

 52.3 30.1   2.515 2.470 2.465 2.328 2.024    

5D120

 59.1 28.2   2.520 2.520 2.479 2.311 1.980    

5D120

 53.5 27.6   2.510 2.510 2.496 2.338 2.169    

5DL13

 60.2 32.0   2.515 2.515 2.515 2.362 1.922 1.463  

5DP2

 60.3 32.4   2.515 2.514 2.513 2.418 2.067 1.418  

5DP7

 57.6 26.4   2.512 2.512 2.440 2.259 1.580    

5E13

 57.5 29.5   2.515 2.515 2.484 2.197 1.803    

5EH7

 57.6 28.5   2.517 2.517 2.473 2.210 1.848    

5EJ11

 60.3 28.5   2.515 2.515 2.515 2.241 1.839 1.420  

5EJ13

 57.8 26.5   2.519 2.519 2.431 2.210 1.766    

5EJ15

       2.52 2.52 2.50 2.28 1.90 1.66  

5EL9

 60.3 27.0   2.517 2.517 2.441 2.221 1.780 1.248  

5EP8

 60.2 33.0   2.513 2.513 2.513 2.245 1.780 1.120  

5F3

 58.0 27.4   2.519 2.519 2.419 2.135 1.863    

5F12

 51.5 23.3   2.021 2.021 1.882 1.631 1.375    

5F16

 59.1 36.7   2.519 2.489 2.489 2.372 2.104    

5F18

 58.0 27.0   2.521 2.521 2.515 2.257 2.006    

5FJ9

 59.2 35.0   2.517 2.517 2.517 2.364 2.021    

5FL7

 58.0 28.0   2.518 2.518 2.440 2.170 1.735    

5FL11

 60.3 28.2   2.518 2.518 2.438 2.175 1.740 1.256  

5FL14

 58.0 28.0   2.520 2.520 2.440 2.170 1.735    

5I4

 60.0 27.0   2.514 2.509 2.442 2.071 1.690 1.332  

5J6

 58.0 27.5   2.518 2.518 2.340 1.890 1.450    

5J9

 58.0 27.0   2.522 2.520 1.432 1.1006 1.505    

5L1

 58.0 27.0   2.518 2.518 2.330 1.811 1.297    

5L14

       2.52 2.52 2.45 2.19 1.78 1.38  
6 Series Needles 30-38 spigot carburetors
Needle X Y Z 10 20 30 40 50 60 70

6CF1

 61.5 29.5   2.512 2.512 2.429 2.240 1.974 1.710

6DH2

 62.3 28.0   2.511 2.511 2.466 2.295 2.000 1.660

6DH3

 62.3 22.0   2.512 2.512 2.458 2.286 1.948 1.607

6DH4

 62.3 25.5   2.520 2.520 2.440 2.258 1.915 1.575

6DH7

 62.2 28.5   2.516 2.516 2.505 2.316 2.009 1.688

6DH21

 52.3 30.1 16.5 2.515 2.470 2.465 2.328 2.024

6DP1

 62.3 28.9   2.511 2.511 2.476 2.312 1.748 1.075

6DP5

 62.3 32.1   2.518 2.518 2.518 2.372 1.834 1.141

6F3

 60.5 34.2   2.512 2.512 2.512 2.313 2.000

6F4

 62.3 32.0 19.4 2.515 2.442 2.436 2.206 1.939 1.678

6F5

 62.3 38.1 19.0 2.515 2.456 2.454 2.364 2.098 1.840

6F8

 62.3 34.0 21.5 2.512 2.512 2.386 2.214 1.945 1.688

6F9

 62.3 28.9   2.516 2.516 2.475 2.210 1.949 1.678

6F16

 59.1 36.7 18.5 2.519 2.489 2.489 2.372 2.104

6FJ6

 62.3 35.2   2.505 2.505 2.505 2.376 2.040 1.606

6FJ11

 62.3 36.0 18.7 2.519 2.481 2.481 2.367 2.030 1.610

6H1

 62.3 37.5   2.510 2.510 2.510 2.412 2.041 1.696

6J1

 64.0 36.2   2.517 2.517 2.517 2.339 1.919 1.495

6J3

 62.3 36.7   2.515 2.515 2.515 2.359 1.912 1.456

6L1

 62.3 37.0   2.512 2.512 2.512 2.335 1.826 1.313

6N1

 62.3 37.0   2.514 2.514 2.514 2.278 1.672 1.058

6F16

 64.6 31.2 18.4 2.520 2.404 2.400 2.201 1.941 1.679
7 Series Needles 40-44 spigot carburetors
Needle X Y   10 20 30 40 50 60 70
7F2 73.0 43.5   2.515 2.515 2.515 2.515 2.312 2.040 1.703
7FO6 72.3 29.0   3.005 3.005 2.951 2.680 2.415 2.140 1.876
7H2 72.3 28.9   3.005 3.005 2.928 2.575 2.230 1.868 1.507
7J2 72.3 28.8   3.005 3.005 2.904 2.460 2.010 1.569 1.125