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