Mikuni Carburetors

October 19, 2016

Contents:
1 a. for 1979-81 Yamaha QT50, VM12-SC-3L5 round float
   b. for 1982-87 Yamaha QT50, VM12-SC-4L4 round float
   c. for 1983-02 Yamaha PW50, VM12-SC-4X4 round float
   d. for 2003-06 Yamaha PW50, VM12-SC-5PG round float
2 a. for 1983-90 Trac (Daelim),  VM13-SC-R4  round float
   b. for 1980-84 Indian AMI50,  VM10-SC-H9  round float
3.    for 1976-80 Angel (TYM),  VM10-24 square twin float 
4.    Other Carbs like Mikuni
5.    Mikuni Jets
6.    Info
7.    Tillotson Carburetor on 1978 Indian AMI-50

These are the baby Mikuni’s, the smallest of the small, 10 to 13mm for limited 50cc engines. See Info below.  


1. Mikuni VM12SC on Yamaha QT50 and PW50

This is a 12mm carburetor (12mm venturi diameter) with a 18mm clamp diameter.

It is not like any common Mikuni for a limited 50cc, like a moped or a kids off road. Apparently, Mikuni made carbs according to to each big manufacturer’s design. So Kawasaki KDX50, Suzuki JR50 have baby Mikuni carbs but with different designs than Yamaha PW50 and QT50. 

VM12SC versions: The first version was 3L5 on 1979-81 QT50. It had an idle air screw just to the left of the idle speed screw. After 1981, on versions 4L4, 4X4, 5PG the air screw was to the right of the idle speed screw. The off road 4X4 and 5PG versions were mostly the same except the cables exited at 90 degrees, with metal curved pipes, instead of straight up.

1979-81 Yamaha QT50
3L5-00 with #75 jet
3L5-01 with #70 jet

1982-87 Yamaha QT50
4L4-00 with #70 jet

1983-02 Yamaha PW50 4X4-00
2003-06 Yamaha PW50 5PG-00

 

 

 

 

 

 

 

 

 

 

Mikuni 3L5, 4L4, 4X4, 5PG

Combined Parts List  A= 3L5 on ’79-81 QT50,  B= 4L4 on ’82-87 QT50
Combined Parts List  C= 4X4 on ’83-02 PW50, D= 5PG on ’03-06 PW50
#  quantities
01 A B C D   Yamaha # xxx price    description
01 1 0 0 0  3L5-14101-01    N/A  carburetor 70 jet 79-81 QT50
01 0 1 0 0  4L4-14101-00    N/A  carburetor 70 jet 82-87 QT50
01 0 0 1 0  4X4-14101-00    N/A  carburetor 70 jet 83-02 PW50
01 0 0 0 1  5PG-14101-00    N/A  carburetor 70 jet 03-06 PW50
02 1 1 1 1  3L5-14181-07    N/A  float bowl
03 1 1 1 1  3L5-14184-00    N/A  float bowl gasket
04 1 1 1 1  620-14231-14 $8.00 main jet 70 M5-0.75 large round
05 1 1 0 0  3L7-14141-10    N/A  needle jet E0 Ø2.05
05 0 0 1 1  3L7-14141-12    N/A  needle jet
06 1 1 1 1  3L5-14142-40 $0.00 idle jet 40 M4-0.7 thread
07 4 4 4 4  98580-04014  $0.70 float bowl screw M4 x 14 phillips
08 1 1 1 1  3L5-14198 00    N/A  top gasket
09 1 1 0 0  3L5-14158-00    N/A  carb top cap
10 2 2 0 0  12G-14106-00 $5.00 cable adjuster-stop M6-0.75 
11 2 2 1 1  802-14161-00 $2.50 adjuster lock nut M6-0.75 x 3 hex9
12 2 2 0 0  8A7-14169-10 $2.00 cable rubber cap
13 1 1 1 1  3L6-14185-01    N/A  float (not Trac, 90 deg different)
14 1 1 1 1  3L5-14190-00  N/A    float needle = Trac 10206
15 1 1 1 1  603-14186-00 $4.00 hinge pin Ø2 x 16
16 1 1 0 0  3L5-14112-25    N/A  throttle slide
16 0 0 1 1  3L5-14112-40    N/A  throttle slide
17 1 1 1 1  3L5-14137-00 $5.00 spring stop “M” clip
18 1 1 1 1  3L6-14116-06    N/A   jet needle 3X1  Ø2.0 Ø1.36 x 30.7
18 1 1 1 1  36R-1490J-06    N/A   jet needle set 17, 18, 20  3X1
19 1 1 1 1  174-14131-01 $9.00 throttle spring Ø10.5 x 52
20 1 1 1 1  127-14137-00 $2.00 jet needle clip    Ø2.0
21 1 1 1 1  3L6-14133-00 $0.00 idle speed screw spring
22 1 1 1 1  36R-14103-00 $0.00 idle speed adjust screw
23 1 1 1 1  58E-14171-00 $0.00 choke plunger
24 1 1 1 1  127-14135-00 $0.00 choke spring
25 1 1 1 1  98580-05012  $0.60 top cover screw M5 x 12 phillips
26 1 1 1 1  92990-05100  $0.25 top screw washer M5 spring type
27 1 0 0 0  3L5-14123-01 $0.00 early idle air mixture screw (’79-81)
28 1 0 0 0  3L5-14962-00 $0.00 early idle air screw washer (81 only?)
29 1 1 1 1  95380-05600  $1.50 clamp nut M5 x 5 hex9
30 1 1 1 1  98517-05030  $0.70 clamp bolt M5 x 30 pan phillips
31 1 1 1 1  90445-05N13  $0.00 drain hose 200mm
32 2 2 2 2  3F7-14134-00  $5.00 air and drain screw spring Ø4.8 x 10
33 1 2 2 2  36R-14104-00  $6.00 air and drain screw M6-0.75×20
34 1 1 1 1  1M3-14997-00   N/A  clamp seal Ø23
35 1 1 1 1  1V3-14271-00   N/A   clamp sleeve Ø18 x Ø23 slotted
36 0 0 1 1 not sold separate
N/A  top cover with curved pipes
39 0 0 2 2  17L-14106-00 $2.50 cable adjuster nut M6-0.75×3 hex9
40 0 0 2 2  17L-14106-00 $6.00 cable adjuster
41 0 0 2 2  180-14169-00 $0.00 cable rubber cap

41 0 0 2 2  WPS-70-1028  $3.00 rubber cap similar, newer style

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2. Mikuni H9-10 on Indian, R4-13 on Trac (Daelim)

H9 is a 10mm carb with a 18mm clamp diameter.
R4 is a 13mm carb with a 20mm clamp diameter.

They look almost the same, and share many parts in common.

1979-84 Indian mopeds, some

1984-90 Trac mopeds with Daelim engine

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Mikuni H9-10 and R4-13

Combined Parts List         L = Trac Liberty, Escot, Image  O = Trac Olympic
0 quantities Trac#  new xx   C = Trac Clipper, Hawk, Sprint   I = Indian AMI50 

0 quantities Trac#  new  
01  L O C I  Trac#  Trac# xxIndian# xx price   description   
00  1 1 0 0  12201 13201 E000-00-00   N/A    carburetor Trac Liberty R4-13
01  0 0 1 0  00000 13202 E000-00-00   N/A    carburetor Trac Clipper R4-13D
01  0 0 0 1  00000 00000 E210-30-50   N/A    carburetor Indian AMI50 H9-10   
01  1 1 1 0  12201 13201 E000-00-00   $75   carburetor body bare Trac
01  0 0 0 1  00000 00000 E210-30-50   N/A  carburetor body bare Indian
02  1 1 0 1  12211 13215 E237-70-50   N/A    needle jet E8 Ø2.05
02  0 0 1 0  00000 13216 E000-00-00   N/A    needle jet D8 Ø2.10
03  1 1 1 1  10206 00000 E238-80-50   N/A    float needle Yamaha 3L5-14190-01
04  1 1 1 0  10201 00000 E000-00-00  $0.00 idle jet 40, thread M4-0.7
04  0 0 0 1  00000 00000 no number     N/A   idle jet not-replaceable, tight press
05  0 0 0 0  00000 00000 E236-00-50  --N/A- main jet 60, M5-0.75 small round
05  0 0 0 1  00000 00000 E236-25-50  $8.00 main jet 62.5  use Dellorto  #60
05  1 1 0 0  12205 13206 E000-00-00  --N/A- main jet 65 use Dellorto 1486 #62

05  0 0 1 0  00000 13207 E000-00-00  --N/A- main jet 70 use Dellorto 1486 #68
06  1 1 1 1  12218 13223 E238-10-50    N/A   float white-clear plastic (not QT50)
07  1 1 1 1  10207 00000 E238-07-50  $4.00 float hinge pin Ø2 x 16
08  1 1 1 1  12203 13204 E238-00-50    N/A   float bowl gasket
09  1 1 1 0  12204 13205 E000-00-00    N/A   float bowl no vent
09  0 0 0 1  00000 00000 E238-30-50    N/A   float bowl w/vent
10  2 2 2 2  10202 00000 E237-06-50  $0.70 float bowl screw M4 x 14 phillips
11  1 1 1 1  12217 13222 E238-12-50  $0.60 top cover screw M4 x 25 phillips
12  2 2 2 2  10203 00000 E237-01-50  $N/A   rubber cap original short
12a2 2 2 2 10203a00000 E237-01-50a $3.00 rubber cap substitute 70-10228c
14  0 0 0 1  00000 00000 E237-02-50    N/A   top cover, smooth cable holes
15  1 1 1 1  12213 13218 E237-04-50    N/A   top gasket
16  1 1 1 1  10204 00000 E238-16-50 $9.00 throttle spring Ø10.5 x 52 
17  1 1 1 1  12207 13209 E237-11-50  $0.00 spring plate (can use “M” clip)
18  1 0 0 0  12210 00000 E000-00-00  $0.00 jet needle 3J2-3 Ø2.0 
18  0 1 0 0  00000 13213 E000-00-00  $0.00 jet needle 3X6-4 Ø2.0
18  0 0 1 0  00000 13214 E000-00-00  $0.00 jet needle 3T6-4 Ø2.0 Ø1.45 x 31.9
18  0 0 0 1  00000 00000 E237-08-50 $0.00  jet needle 3G1-6 Ø2.0 Ø1.40 x 34.4 

19  1 1 1 1  12206 13208 E237-12-50  $2.00 needle clip    Ø2.0
20  1 1 0 1  12216 00000 E238-14-50    N/A   throttle slide Ø14 x 20, says 2.0
20  0 0 1 0  00000 13221 E000-00-00    N/A   throttle slide Ø14 x 20, says 4.0

21  1 1 1 1  12213 13218 E237-04-50  $1.50 clamp nut M5 x 4 hex9
22  1 1 1 1  12220 13225 E238-02-50  $0.00 choke spring Ø6 x 19
23  1 1 1 1  12219 13224 E238-06-50  $0.00 choke plunger Ø8 x 20
24  1 1 1 1  12212 13217 E237-05-50  $0.60 clamp screw M5 x 25 phillips
25  1 1 1 1  12208 13210 E237-10-50  $9.00 idle spd screw M6-0.75×17 short tip
26  2 2 2 2  12209 13211 E237-09-50  $5.00 idle screw spring Ø4.8 x 10 (used 9)
27  1 1 1 1  10205 00000 E238-18-50  $6.00 idle air screw M6-0.75×20, long tip
28  2 2 2 0  10208 00000 E000-00-00  $N/A   cable rubber boot original
28a2 2 2 0  10208a 0000 E000-0 0-00  $2.00 cable rubber boot substitute 1476-06
29  2 2 2 0  10209 00000 E000-00-00  $6.00 cable adjuster-stop M6-0.75×16 hex7
30  1 1 1 0  12215 13220 E000-00-00   $19   top cover, threaded cable holes
31  4 4 4 0  10210 00000 E000-00-00  $3.00 adjuster lock nut M6-0.75 x 2 hex7
32  2 2 2 0  12222 13227 E000-00-00  $0.00 cable curved pipe M6-0.75
33  0 0 0 1  00000 00000 E000-00-00    N/A  clamp sleeve Ø18 x Ø23
33  1 1 1 0  00000 00000 E000-00-00    N/A  clamp sleeve Ø20 x Ø23

Mikuni cable rubbers

Indian Mikuni idle hole before and after drilling

 

 

 

 

 

 

 

 

Indian Mikuni carb service

The idle hole is often blocked. There are three spray holes, the main and mid-range under the throttle slide, and the smaller idle hole downstream of the throttle slide. When the bike is idling the slide is down and only the idle hole is active. A small slit of air under the slide blows over it, creating the suction and breaking up the liquid gasoline into small droplets. The drill size is tiny, a #76 which is 0.020 inch. The drill is held in a pin vise. The pin vise goes into the drill chuck. After about 2mm of depth there is a empty chamber behind the hole. That chamber leads to the idle jet which is at the top of a vertical tunnel-tube made into the zinc casting. The idle jet can be cleaned separately from below. It is smaller, like maybe 0.010 inch. That is smaller than the smallest drill #80 in a numbered set.

Carb spray is used to tell if the idle hole or idle jet is clogged. When sprayed up from the vertical idle tunnel-tube, the spray should shoot out from the mid range hole and dribble out from the idle hole.

 


3. Mikuni VM10-24 on Angel (TYM) mopeds

This carb is on Taiwan-made Angel and Speed Bird mopeds. It is a 10mm carburetor with a 20mm clamp diameter.

It is a 1960’s to early 70’s design, like a 1965 Yamaha U5 Newport, or a 1970 Suzuki F50 Cutlass carburetor. It has a brass swinging twin-float and a replaceable float needle seat. It has nothing made of rubber in it, unlike more modern carburetors. 

1977 Angel AP48

1983 Angel BP48-S carb

1979 Angel BP48-S

1977 Speed Bird BP48

 

 

 

 

 

 

 

Mikuni VM10-24

Parts List
 #    Angel part #  Trac#   price      description
00  786-01-31000 00000     N/A  carburetor assy
01  786-01-3100a 00000  $0.00 carburetor body bare
02  786-01-31510 00000  $0.00 cable rubber boot
03  786-01-3110a 00000  $0.00 carb top M20-1.0 thread
04  786-01-31440 00000    N/A  throttle spring Ø13 x 38 stiff original
04  786-01-3144a 00000  $6.00 throttle spring Ø13 x 50 soft substitute
05  786-01-31380 00000  $0.00 spring plate Ø13 Ø2.5
06  786-01-31340 13208  $2.00 needle clip Ø2.0
07  786-01-31330 00000    $15  jet needle 3G9  Ø2.00 Ø1.60 x 34.4
08  786-01-31470 00000    $45  throttle slide Ø16 x 23.5, says 2.0
09  786-01-3120a 00000  $5.00 cable adjuster-stop M6-0.75  hex7
10  786-01-3120b 10210  $3.00 adjuster lock nut M6-0.75 x 2 hex7
11  786-01-3120c 00000  $0.00 choke housing M10-1.0 thread, pipe thread subst?
12  786-01-31490 00000  $0.00 choke spring Ø6.5 x 23 stiff
13  786-01-31480 00000  $0.00 choke plunger Ø8 x 17.5
15  786-01-31520 13218  $1.50 clamp nut M5 x 5 hex9
16  786-01-31530 00000  $0.00 clamp screw M5 x 27 slot-hex8
17  786-01-31450 13211  $5.00 idle (both) spring Ø4.8 x 10
18  786-01-31460 00000  $6.00 idle air screw M6-0.75×19, long tip (-1)
19  786-01-31540 13210  $9.00 idle speed screw M6-0.75×17 short tip
20  786-01-31370 00000  $0.00 idle jet 15
21  786-01-31320 00000  $0.00 needle jet E2-137 Ø2.05
22  786-01-31300 00000  --N/A- main jet 45 M5-0.75 small hex
23  786-01-3139a 00000  $0.00 float seat seal washer Ø7 x Ø10
24  786-01-3139b 00000  $0.00 float valve seat M7-0.75 thread hex8
25  786-01-3139c 00000  $0.00 float valve needle
26  786-01-31350 00000     N/A  float
27  786-01-31410 00000  $4.00 float hinge pin Ø2.5 x 23
28  786-01-31360 00000     N/A  float bowl gasket
29  786-01-3100b 00000     N/A  float bowl
30  786-01-31430 10202  $0.70 float bowl screw M4 x 14 phillips
31  786-01-3100c 00000  $0.00 float overflow hose Ø3 x 200
32  786-01-3100d 00000     N/A  clamp sleeve with lip Ø20 x Ø23 x 15.5
34  786-01-3110b 10209  $6.00 cable adjuster-stop M6-0.75 x 16 female hex7
35  786-01-3110c 00000  $3.00 adjuster lock nut M6-0.75 x 2 hex7
36  786-01-3110d 00000  $0.00 carb top rubber cap
37  786-01-3110e 00000  $0.00 curved pipe cable guide

 

Angel Carb Service:

Angel service p9

Angel service p10

Angel service p11

Angel service p12

 

 

 

 

 

 

 

 

 

 

 


4. Mikuni design

A. Pacco

The India-made Pacco P-60 MT carburetor used on 2000-2002 Avanti mopeds

Pacco P-80 MT carburetor 21mm clamp diameter, same as Dellorto SHA 15/15

Pacco P-60 MT carburetor, 21 clamp diameter
Left, Dellorto SHA 15/15, same 21 clamp size

avanti-pacco-carburetor-16-0-mm-slide-and-top-parts

Pacco P-60 MT carburetor, 16mm slide parts

 

 

 

 

 

 

 

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B. Mikcarb

The India-made Mikcarb is used on 2005 Hero Majestic Pacer. It looks identical to Pacco P-60, except it has a cable choke instead of a flip lever.

Mikcarb on 2005 Hero Majestic Pacer

 

 

 

 

 


5. Mikuni Jets

Small Hex used on 1960’s-70’s Yamaha and Kawasaki
045    --N/A-  Angel #786-01-31300
050      N/A

060      N/A

0
70    $3.00
0
75    --N/A-
080    $3.00
085    $3.00

090      N/A
100      N/A

Small Round used on many Yamaha, Kawasaki, and Suzuki products
060    --N/A- Indian #E236-00-50
062.5 $8.00  Indian #E236-25-50
065    --N/A-  Trac #13206
070    --N/A-  Trac #13207
0
75    --N/A-
080    --N/A-
090      N/A
100      N/A
110      N/A
116    $3.00
118    $3.00
120    $3.00
124    $2.50
132    $2.50
140    $3.00
150    $2.00
155    $2.50
160    $3.00

Large Round  used on many Yamaha, Kawasaki, and Suzuki motorcycles
060    --N/A-
062.5 $8.00
065    --N/A-
070    $8.00  Yamaha #620-14231-14-00
0
75    --N/A-
080    --N/A-
090      N/A
097.5 $2.50
100    $2.50
102.5 $2.50
105      N/A
107.5 $2.50

110    $2.50
112.5 $2.50
115      N/A
117.5   N/A

120    $2.50
122.5   N/A
125    $2.50
127.5 $2.50
130    $2.50
132.5 $2.50
135      N/A
137.5 $2.50
140    $2.50
142.5 $2.50
145   
$2.50
147.5 $2.50
150    $2.50

152.5 $2.50
155    $2.50
157.5 $2.50

 


6. Info

These are the baby Mikuni’s, the smallest of the small, 10 to 13mm for limited 50cc engines. Unlimited 50cc like Kawasaki AR50 or Yamaha YSR50 have 18mm size carburetors. Those are bigger babies, but still “off the charts”.

USA motorcycle parts suppliers commonly have parts for 28 to 44mm Mikuni VM series (classic round slide) carburetors. They have 2.5 or 3.0mm jet needles, not 2.0 like the “babies” have. Their float needles are also bigger.

Yamaha, Suzuki, and Kawasaki supply some parts for the small Mikuni carburetors that are on their 50cc models.

 

Carb clips

 

Jet Needle Clips are tiny and get lost easily. The full name of that kind of clip is “metric side-mount external retaining ring (E-style)”. The clip size for moped carburetors is smaller than any motorcycle carburetor clip, because the jet needle and everything else in the carburetor is smaller. A 10mm Indian moped carb jet needle is 2.0mm thick with a 1.5 clip groove. Mikuni carbs 18mm and up have needles 2.5mm thick with a 1.9mm clip grooves, or bigger.

 

 

 

 

Sources:

  1. Parts Catalogs provided illustrations, part numbers, descriptions, applications, and some specifications.
  2. Service Manuals provided most specifications.
  3. Packaging Labels on some new parts provided part numbers and applications.
  4. Markings on some used parts provided specifications.
  5. Direct Measurement on most parts provided specifications.
  6. Internet Images provided some identification by photo-matching, and occasionally dimensions by photo-scaling.

 

 


7. Tillotson Carburetor on 1978 Indian AMI-50

Tillotson carb kit

 

Tillotson Carburetor Parts (none)
    E210-12-50 Tillotson carb comp.   none  has no float reservoir
These have an adapter “bell” for the air filter, to interchange with Keihin.
These did not work well when they were new with fresh rubber back in 1978.
Tillotson carbs were replaced by Keihin, only months after they came out.
40 years later in 2018 their rubber parts, especially the diaphragm, are all stiff.
This is the Tillotson carb kit for Indian, Rk-32Hk, available on Amazon.

 

 

Tillotson carb, front and back view

Tillotson carb on 1978 Indian

 


Jet Drills

January 27, 2007

 

Above, a Tomos A55 idle jet (M4 thread) is physically bigger than a Puch Maxi main jet (M3.5 thread), but the hole size is much smaller. The photo shows how the #25 jet, 0.010" (ten thousandths of an inch), will allow the thinner wire of the wire wheel to pass through the hole, but not the thicker wire of the wire brush. This is a useful cleaning technique.

Above, a Tomos A55 idle jet (M4 thread) is physically bigger than a Puch Maxi main jet (M3.5 thread), but the hole size is much smaller. The photo shows how the #25 jet, 0.011″ (eleven thousandths of an inch), will allow the thinner wire of the wire wheel to pass through the hole, but not the thicker wire of the wire brush. This is a useful cleaning technique.

This will help you visualize how small these drills and jets are!

Moped main jets range from 0.018″ (#77 drill) to 0.026″ (#71 drill). 

Moped idle jets, like Tomos A55, are 0.011″ (smaller than #80).

An average human hair is 0.003″ (three thousandths of an inch).

So moped jet holes are 4 to 9 hairs wide!

Shauns well used jet drill container from the 1980's

Shaun’s well used drill container from 1987

 

Jet Drills: All through the late 1980’s and 1990’s, Shaun (at Royal Cyclery and later at Myrons Mopeds) used the USA-made jet drills to service carburetors. The drill sizes are an American wire gauge. They did not vary in size. Those 20-piece Drill Sets 61 to 80, cost $40 in 2015, $33 in 1998. and $29 in 1987. Some are in clear plastic round dome containers, and some are in conventional metal drill set boxes.

 

 

Drill Set 61-80 USA-made

Drill Set USA-made

Jet Drills made in China

Set 1 China-made

China-made Drills: In the 2000’s there were many China made tools sold in “surplus” tool stores. The China made 20-piece Drill Sets 61 to 80, sell for $7 to $10, or one fourth as much. They have an excellent blue plastic container, that only lets out one at a time. But the drill sizes are all wrong. From about 2010 to 2014, Myrons Mopeds sold these inexpensive drill sets, not knowing that the drill sizes were inexact, to say the least.

So although the China sets cost one forth as much, they only have about seven or eight different sizes, and they lack the smaller sizes below 0.4 (or sometimes 0.6) mm. Each set is different.

 

Jet Drills made in USA

Jet Drills made in USA

Set 2 China-made

Some have poorly made drills, twisted funny, bigger at the cutting end, or lumpy, varying in thickness. Some have poorly made cutting tips, so they might wander, grab and break, or not cut well.

Despite the poor quality and inexactness, the inexpensive drills are still useful for cleaning purposes, but not for measuring and maybe not for drilling. Fortunately, brass carburetor jets are the easiest thing to drill, with a drop of oil and a pilot hole already there.

 

 


Micro Drills and Wires for Sale Individually

These drills are measured at the shank (the smooth part). At the cutting edge they are 1 or 2% bigger.

These wires are steel guitar strings, cut into 5 inch lengths. 

“Metric” jets have a number that literally means hundredths of a millimeter, so a 64 jet is 0.64 mm.

Micro Drills for sale

inch   mm/#  price     moped jets that it cleans
0.011   wire     N/A Gurtner Motobecane diffuser – two idle holes (.013)
0.0135 #80  $6.00
0.0145 #79  $5.00
0.0157 0.40  $3.00 Dellorto 38 (.0162), Bing 42 (.0162)
0.016   #78  $4.00 Dellorto 40 (.0168), Bing 44 (.0167)
0.017   wire  $0.50 Dellorto 42 (.0177), Bing 46 (.0175)
0.018   #77  $3.50 Dellorto 44 (.0186), Bing 50 (.0188)
0.019   ——  $2.00 Dellorto 46 (.0194), Bing 52 (.0194)
0.0197 0.50  $2.00 Dellorto 48 (.0202), Bing 54 (.0200), “Metric” 51 (.0201)
0.0200 #76  $3.50 Dellorto 49 (.0207), Bing 56 (.0206), Gurtner 210=52 (.0210)
0.021   #75  $4.00 Dellorto 51 (.0215), Bing 58 (.0213), Gurtner 220=54 (.0220)
0.0225 #74  $5.00 Dellorto 55 (.0231), Bing 62 (.0229), Gurtner 230=56 (.0230)
0.023   ——  $2.00 Dellorto 56 (.0235), Bing 64 (.0234), Gurtner 240=58 (.0236)
0.0235 0.60  $2.00 Dellorto 58 (.0242), Bing 66 (.0239), Gurtner 245=59 (.0239)
0.0235 0.60  $1.50 Dellorto 58 (.0242), Bing 66 (.0239), Gurtner 250=60 (.0242)
0.024   #73  $3.00 Dellorto 60 (.0247), Bing 68 (.0248), “Metric” 63 (.0248)
0.025   #72  $3.50 Dellorto 62 (.0255), Bing 70 (.0254), “Metric” 65 (.0256)
0.026   #71  $4.50 Dellorto 66 (.0268), Bing 74 (.0267), “Metric” 68 (.0268)
0.0275 0.70 x N/A  Dellorto 70 (.0280), Bing 78 (.0280), “Metric” 71 (.0280)
0.028   #70  $4.00 Dellorto 72 (.0287), Bing 80 (.0287), “Metric” 73 (.0287)
0.0292 #69  $4.50 Dellorto 78 (.0306), Bing 84 (.0301), “Metric” 77 (.0303)
0.030   wire     N/A Dellorto 80 (.0312), “Metric” 79 (.0311), Gurtner K80 (.0311)
0.031   #68  $4.50 Dellorto 82 (.0318), “Metric” 81 (.0319)
0.0315 0.80  $2.00 Dellorto 84 (.0324), “Metric” 82 (.0323)
0.032   #67  $3.00 Dellorto 86 (.0331), “Metric” 84 (.0331)
0.0325  —— $2.00 Dellorto 88 (.0337), “Metric” 86 (.0339)
0.033   #66  $4.50 Dellorto 90 (.0343), “Metric” 88 (.0346)
0.034   wire     N/A “Metric” 90 (.0354)
0.035   #65  $3.00 “Metric” 92 (.0362), Gurtner MB (side mount) diffuser (.0358)
0.0354 0.90  $2.00 “Metric” 94 (.0370)
0.036   #64  $3.00
0.037   #63  $2.50
0.038   #62  $1.50
0.039   #61  $1.50
0.0394 1.00  $1.00

 


Deluxe 40-piece Micro Drill Set

Jet Drills 80-72 and 71-60

Myron’s Mopeds two case deluxe micro drill set, 80 to 72 (small) and 71 to 60 (large) plus many in-between sizes.
Price $45

Slide clear top plastic until hole is over drill (and pointer is on desired drill number). Only lets one drill out at a time. Never take out more than one at a time, or they can get mixed. The case keeps them organized. If any get lost, dull, or broken, individual drills can be bought at some hardware stores for $3-$4 each.

Useful for sizing to tell how big a jet really is (sometimes they’re drilled out or labeled wrong).

Useful for cleaning varnish or corrosion coating the inside of an old jet. It doesn’t really clean out any other way. The drill is used as a file, held with a needlenose pliers.

Useful for drilling jets to make a new size, as an alternative to buying ones. The drill is held with a needlenose pliers, and the jet is rotated with your fingers, with a drop of oil. To go down in size, fill the hole with solder and re-drill it smaller.

 

 

 

Here is a pin vise, a mini drill chuck, price $8

 

 

 

 

 

 

 


Other Tools for Cleaning Jets

Using a micrometer to measure a 0.017 wire

Using a micrometer to measure a 0.017″ wire

Guitar steel string 17 thousandths of an inch

Guitar string

Guitar Steel Strings in the smaller sizes are excellent tools for cleaning small holes. Here is a 0.0170 inch steel wire guitar string, perfect for cleaning out a 1974-85 Tomos stock jet size 46 that has a 0.0175 inch hole. A Honda Express NC50 (Keihin) carburetor, has a long brass idle jet tube with a tiny jet hole at the far end, too far for a drill to reach. For that, only a 2 or 3 inch piece of 0.010″ steel guitar string will reach to clean it. Ultrasonic cleaners, carb spray, or soaking are not effective for that. Other examples are a Sachs 52 jet 0.0190 would be cleaned by a 0.018″ wire, or a Motobecane 230 jet 0.023″ would be cleaned by a 0.022″ wire. The wire has to be a little smaller than the hole. Plain steel strings range from 0.008″  to 0.017″ in steps of 0.001″. Wound strings range from 0.017″ to 0.065″. 

 

Torch Tip Cleaner Set

Torch Tip Cleaner Set

Root Canal Files

Root Canal Files (say ahhh)

Welding Torch Tip Cleaners are another excellent tool for cleaning small holes. The tip has a cutting surface but not the sides. So it is made to clean the hole without widening it.

Wire Feeler Gauge Sets: There are also wire gauge measuring sets that look the same as the torch cleaner set shown.

Dentist’s Root Canal Files are also good for cleaning small holes. Color coded files range from 0.06 to 1.10 mm (0.0024 to 0.0433 inch).