Myrons Mopeds

3. ULO Tail Lights

ULO made tail lights, reflectors, and turn signals for German mopeds, Hercules (Sachs), Kreidler, Solo, Kynast, and tail lights for many non-German mopeds, Batavus, Sparta, Puch, Peugeot, Motobecane and Honda PA50. ULO was founded by Moritz Ullman in 1947 in Geislingen Germany. Ullman knew how to make molded glass products, like bicycle reflectors. Today ULO is worldwide, making tail lights for cars like BMW and Audi.

ULO plastic parts have a date mark. The lens has the compliance standards and those have a start date.

ULO 250 xxxxxxx ULO 248
1972-78 xxxxxxxxx 1978-84

1975 ULO 250-1
72-75 lens 250-0015
one bulb 6V 18/5W

1977 ULO 250-2 
76-84 lens 248-0015
upper bulb 6V 10W
lower bulb 6V 5W

1978 ULO 248-1 
lens 248-0015
one bulb 6V 18/5W

1978 ULO 248-2 
lens 248-0015
upper bulb 6V 10W
lower bulb 6V 5W

ULO 248-3 with ignition
ground resistor on brake
upper bulb 6V 10W brake
lower bulb 6V 5W tail

Left ULO 248-1, right 248-3

ULO 250-1 (nicer than the one for sale)

ULO 250-2 good used for sale below

ULO 250 and ULO 248 parts

60a ULO 250-1 $63 used 250-1 1-bulb tail light
60a ULO 250-2 $73 used 250-2 2-bulb tail light
60b ULO 248-1  N/A used 248-1 1-bulb tail light
60b ULO 248-2  N/A used 248-2 2-bulb tail light
60b ULO 248-3 $75 used 248-3 2-bulb tail light
60b ULO 248-3 $00 with ignition ground resistor

61a 250-6017 $65 ULO250 housing used
61a 250-hous $30 SIM250 housing replica modified
61a 250-hous $00 lens screws must be 5mm shorter
61b 248-6017 $20 ULO248 housing used broken

62x 250-pum 50¢ Puch upper bolt M5x32
62a 250-upm 50¢ 250 upper bolt M6x32
62b 248-upm 50¢ 248 upper bolt M6x25

63a 250-lnscr $1.00 250 lens screw ST x 55
63a 250-short $2.00 shortened screw ST x 50
63b 248-lnscr $1.00 248 lens screw M4 x 45

64x 248-0015 $35 red lens used 1976-1984
64a 250-0015 $45 red lens used 1972-1975

65x 250-gask  $$7 ULO 250 lens gasket
65x 250-gask  $$0 not for ULO 248 or SIM 250

66x 250-tail  $2.00 6V 5W lower bulb
67x 250-stop $2.00 6V 10W upper bulb
67a 248-bulb $2.00 6V 21/5W dual bulb

SIM 250 housing, R original, L modified
(posts lowered 2mm, wires hole widened
and upper mount hole drilled)

68x 250-lomb $0.50 “Puch” lower bolt M5x16
68a 248-lomb $0.50 non-Puch lower bolt M6x16
68c 248-lwas  20¢ non-Puch lower mnt washer M6

69x 250-csh1 $$9 cushion foam (only on some)
69a 250-csh2 $$9 cushion thick (only on some)
69b 250-csh3 $$9 cushion thin (only on some)

70x 250-locw  20¢ “Puch” mount lock washer M5
70a 248-locw  20¢ non-Puch mnt lock washer M6

71x 250-mnut 25¢ “Puch” mount hex nut M5
71a 248-mnut 25¢ non-Puch mount hex nut M6

72x 248-grom $$1 grommet for 2-bulb mirror

73x 248-0016 $25 used bulb holder-mirror 2-bulb
73a 250-0016 $13 new bulb holder-mirror 1-bulb

69a thick on top, 69b thin, flat, 69 foam, flat

The little rubber grommets #72 for the two-bulb holder-mirror, are important. When one is missing, the bulb holder is loose. Engine vibration causes the loose holder to “buzz” or vibrate and rub against the lens and housing. The buzzing causes the bulbs to burn out, and produces white powder. The white plastic dust or powder is evidence of “buzzing”.  Slices of small rubber hose can be good substitutes.

3a. Replica ULO Tail Lights

SIM 250

SIM 250 tail light, bulbs 12V 10W and 12V 5W
has no upper mount hole, loose bulb sockets

SIM 250w modified to accept original wires

SIM 250m2 modified with ULO 2-bulb holder

SIM 250 on a Batavus fender 16″
with cushion 69b, sold separately

60s $25 SIM 250 tail light, sold as is
60s $42 SIM 250w for original wires
60s $48 SIM 250m1 with ULO 1-bulb holder
60s $55 SIM 250m2 with ULO 2-bulb holder

The SIM 250w, 250m1 and 250m2 allow the original wires to be reused. The wire connectors are protected inside the light, unlike a plain SIM 250 where they are under the fender. There the tire can rub on the wires when going over bumps or with heavy a load, eventually causing damage. 

61s $15 SIM 250 housing
The SIM 250 housing has no upper mount hole, so a 6mm (15/64″) hole must be drilled.  

63s $$1 SIM 250 lens screw 44mm

SIM 250 2-bulb holder

64s $12 SIM 250 red lens
The SIM 250 lens is 2mm taller on top, and the screw hole tubes are spaced 2mm farther apart. So the lens does not fit an original ULO 250 housing.

66s $$2 SIM 250 lower bulb 12V 5W

67s 0$2 SIM 250 upper bulb 12V 10W

73s $12 SIM 250 bulb holder-mirror
The SIM 250 bulb holder-mirror is different, a metal plate with plastic bulb sockets that are loose. The bulb sockets have 3mm male blade connectors, instead of 8mm male blades like the originals. So the original wires with 8mm female blade connectors will not fit. 

Right, ULO 250 2-bulb holder
Left has the top lowered by 2mm, and lens screw holes slotted

SIM 250m1 and 250m2 modified replica tail lights replace ULO 250-1 and 250-2 originals. They are made from a SIM 250 with the bulb holder-mirror changed to an original type.

The benefits are 1) solid bulb sockets for less bulb burn out, 2) uses the same original wires, 3) can also be one-bulb type for US-model mopeds with external ignition ground brake light wiring.

Modifications to the housing: The upper mount hole is drilled. The lens screw posts are reduced in height. The wires hole is widened enough to pass the female 8mm blade connectors through.

Modifications to the bulb holder: The top is cut down by 2 mm and the screw holes are moved 2 mm farther apart by grinding off the outer edge.

Modifications to the lens: None.

Modifications to the lens screws: The ST self-tapping screws are shortened to 50 mm.

4. Peterson Tail Lights

Peterson tail lights, made in Grandview, Missouri USA, were on ’76-80 Jawa and ’76-77 Derbi mopeds.

Peterson PM420

Peterson PM-420 1960’s – 70’s trailer tail light
used on 1976-77 Jawa Babetta (USA models)

–   3296-061  N/A  Tail Lamp PM420
1   3296-061  N/A  Lamp housing
2    3296-061 N/A Lens used PM420-15
3  34544-001 50¢ Lens screw ST (2)
4      34213 $1.00 Nut 3/8-24 fine
5      34213    50¢ Lock washer 3/8″
6      60507  $2.00 Bulb 6V 21/5W #1154

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Peterson PM-421 meets 1970’s US safety standards for motorcycle tail lamps (shines to the sides). Also has built-in side reflectors, eliminating the need for separate ones. Used on 1978-80 Jawa, 1976-77 Derbi, and not many others. 

–  70106  N/A Tail lamp used PM-421
1  70100  $33 Housing-mirror used PM-421
2  70101  N/A Lens cover new PM-421-15
3  70102  N/A Lens screw ST (3)
4  70103  N/A Mount screw ST (3)
5  60507  $2.00 Bulb 6V 21/5W #1154

Peterson PM-421 tail light

6  422-10  $19 plastic mount PM-422-10
7  422-24  $$6 mount rubber PM-422-24

Jawa metal mount

PM-422 plastic mount

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5. Stanley Tail Lights

Dozens of different Stanley tail lights, made in Japan, are on most Honda motorcycles and mopeds. Here we focus on those used on mopeds and small motorcycles.  

Stanley 040-4765 tail light

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Stanley 040-4765, used on 1977-85 General (top-tank), Lazer (top-tank) and compatibles, made in Taiwan.

1  $55 lamp assembly
2  N/A chrome housing-mirror
2  N/A (2) M6 threaded holes spaced 90mm
3  N/A mount bracket (not shown)
4  $2.00 bulb 6V 21/5W
5 $10 lens gasket (new)
6 $1.00 lens screw M4x55 phillips
5 $$2 can be longer M4x72
7  $35 red lens (new)
$25 red lens new with cracked clear bottom

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Stanley HM-23RC tail light

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Stanley HM-23RC, used on 1977-83 Honda Express NC50 and Express II NA50, made in Japan.

1 N/A lamp assembly
2  $45 black housing-mirror-mount with license mount
2  N/A (3) M6 bolt-thru rubber mounts
4  $2.00 bulb 6V 21/5W
5 $$9 lens gasket (used)
6 $$3 lens screws ST (2) 60mm
7    $8 red lens (used, side reflectors broken off)

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Stanley HM-42RC tail light, with NS50 mount

Stanley HM-42RC, used on 1984-85 Honda Spree NQ50, 1990 Honda NS50, and other late 1980’s Hondas.

1  $45 lamp assembly, without mount
2  $35 black housing-mirror
2  $45 (2) M5 threaded holes spaced 100mm
3  $10 black mount for NS50 (shown)
2  $18 black mount for NQ50 with license mount
4  $1.20 bulb 12V 21/5W
5 $12 lens gasket (used)
6 $$3 lens screws ST (2) 40mm
7  $15 red lens (used)

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6. Cat Eye Tail Lights

Cat Eye reflectors, lights, and turn signal kits, for bicycles and mopeds, were made in Japan.

Cat Eye TL-800 tail light with mount

Cat Eye TL-800, used on 1977-85 Taiwan mopeds, Indian, Angel, General (step-thru) and compatibles.

1 $70.0 lamp assembly, with mount
2 $42.0 chrome housing-mirror 35mm holes
3 $35.0 black metal mount for General step-thru (shown)
4 $2.00 bulb 6V 21/5W #1154
5 $12.0 lens gasket (used)
6 $1.00 lens screw M4 x 50 phillips
7 $32.0 red lens 35mm hole spacing

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7. Saturnus Tail Lights

Saturnus tail, turn and head lights were made in Ljubljana, Slovenia. Saturnus tail lights were only on 2012-13 Tomos mopeds (US models), but they have been on European models for decades. 

 Saturnus 2-bulb tail lamp parts, from 2012 Tomos USA Parts Manual.

#  part#  price  qty    description
30  223572  N/A   1  Rear lamp 2012-on
31  044698 $1.50 1  bulb 12V/5W  BA15S
32  044689 $1.50 1  bulb 12V/10W BA15S
33  044439  $$1   2  Lens screw ST 3.9×16
34  236963  N/A   1  Rear lamp holder (mount) 2012-on
35  026690 $1.50 2  Screw M6x16 button-head allen
36  031509  20¢   2  Washer 6
37  222187  $$8   2  Distance tube 6x10x7.5 (not 6x9x5.5 like pre-2012)
38  219946  $$5   2  Vibration rubber for taillight xxx (same as pre-2012)
39  031925  20¢   2  Washer 6 xxxxxxxxxx   (lower is same as pre-2012)

Saturnus tail light

40  044284 $1.00 2  hex bolt M6x22 xxxxxx  (not M6x20 like pre-2012)
41  217674  50¢   2  Washer 6.4×16 xxxxxxx (not 8.4×16 like pre-2012)
42  030040  50¢   2  Nut M6 self-locking (not shoulder nut like pre-2012)

The fender mount was made to interchange with CEV 9417. The upper 6mm stud on CEV 9417 was very short. That made the special shoulder nut necessary, on 1978-2012 Tomos with CEV 9417. This Saturnus mount uses separate bolts, which are longer. That eliminates the need for a more costly shoulder nut. So Saturnus mount uses a 2mm shorter nut, 2mm longer bolt, 2mm longer spacer. This makes the bolts/nuts 2mm closer to the rear tire.  

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8. Fiem Tail Lights

Fiem tail and turn lights are made in India. On US models, Fiem rear lamps are on early 2000’s Hero Pacer, Panther, Ankur (Hero Majestic), Cosmo Stinger (Mont) and Avanti Autopower, Mont, Supersport, Kobra (Mont) mopeds.

Fiem tail light on Hero Pacer

Fiem tail light on Avanti Autopower

These two lights are the same. The Avanti one is missing the lower red reflector and left side reflector. The Hero one is missing the right side reflector. The top bulb is bigger for the brake light, 12V 10W with base BA15S (bayonet 12 mm single contact). The bottom bulb is smaller for the tail light, 12V 4W with base BA9S (bayonet 9 mm single contact). The tail light also illuminates the license plate through a clear bottom in the red lens.

The Avanti wire colors are yellow = tail, green = brake, black = ground. See wirings for more.

Inline Fuel Filters

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C1 3/16″ inline filter, round screen type, 12-1585 $5

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C2 1/4″ inline filter, round screen type, 15-1520 $6

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C3 1/4″ inline filter, 90 deg paper type, 15-1796 $3

Screw-on Adaptors

C4: 10×1 male to 12×1 male adapter  N/A

C4 adapter
a) separate (yellow box)
b) assembled with valve
c) installed in 10×1 tank

McMaster-Carr 50915K317 fitting, end cap discarded,
1/8 npt-17 to 1/2-24
can be rethreaded
to 10×1 and 12×1

Sometimes a gas tank has a 10 x 1 threaded gas valve hole that is close to a “wall”, preventing the gas valve from screwing on or off, unless the tank is removed. Sometimes removal of the tank is very difficult, like on a Cimatti City Bike. In those cases an adaptor fitting can be used to convert to a turn-buckle type gas valve, where only the nut turns. 

A 5/16″ OD hydraulic tube fitting has a 1/2-24 thread, that can be cut down (rethreaded) to 12 x 1.  The end cap is not used. Then it becomes a moped gas valve adapter. A tight-fitting 10mm washer made of plastic, paper, or other semi-hard material provides the seal, not the threads. The 12×1 die is not in most metric die sets.

Screw-on Extenders

What is an extender and when is it needed? An extender is a piece that moves a M10-1.0 screw-on valve away from the tank.

1. For when the petcock handle hits the tank in the up (reserve) position. Most original valves had reserve pointing up, ↑reserve  off→ on↓. Original valves with an up position often had to be moved away from the bottom of the tank with an extender, to allow the handle to go straight up and not hit the tank. Some tanks had a welded-on extender, a short pipe with a 10×1 threaded hole. Some original valves had screw-on extenders. 

For this reason, most modern replacement petcocks do not have an up position. They have ←reserve  on↓ off→. That eliminates the need for an extender, a cost saving improvement.

2. For when the petcock passes through a hole in a body panel. The correct extender length lowers the petcock to the level needed to pass through a hole in a cover panel. So the petcock is hidden except for the handle, for a clean look.

3. For when something prevents installation. Sometimes part of the gas tank or frame prevents the screw-in petcock from screwing in. An example is Peugeot 102.

..part#  price  extension
C10.11   $13  11.0 mm = 10.0 mm extender + 1 mm seal washer
C

C10.12   $14  12.0 mm = 10.0 mm extender + 2 mm seal ring
C

C10.145 $13  14.5 mm = 13.5 mm extender + 1 mm seal washer
C

C10.155 $14  15.5 mm = 13.5 mm extender + 2 mm seal ring
C

C10.195 $14  19.5 mm = 13.5 mm extender + 6 mm cup seal
C10.195 $00  1980 Peugeot 102 SP (required)

C10.22   $26  22.0 mm = 10+10 extenders + 1+1 seal washers
C

C10.23   $27  23.0 mm = 10+10 extenders + 1+2 seal washers
C

C10.25   $13  25.0 mm = 24.0 extender + 1 mm seal washer
C

C10.26   $14  26.0 mm = 24.0 extender + 2 mm seal ring
C

C10.30   $14  30.0 mm = 24.0 extender + 6 mm cup seal
C

Seal Rings

C13 seal ring    10-14 x 6  w/metal cup 10.4-16-4.5  $2
continued soft, for light tightening, seals over a wide range

C14 seal 0-ring 10-15-2.5 w/metal cup 10.4-15-3.5  $2
continued soft, for light tightening, seals over a wide range

C15 seal ring   10.0 id, 13.7 od, 1.8-2.3 tall nylon $2.00
continued hard, can hold up to tightening pressure

C16 seal ring     7.5 id, 10.5 od, 1.7-2.1 tall nylon $2.00
continued hard, can hold up to tightening pressure

C17 seal ring     7.9 id, 10.4 od, 1.4-1.8 tall fiber  $2.00
continued hard, can hold up to tightening pressure

C18 seal ring     8.0 id, 11.7 od, 0.0-1.0 tall fiber  $2.00
continued hard, can hold up to tightening pressure

Many more of these are listed in Parts/Engine/Seals and O-Rings

Turnbuckle type nuts (forward and reverse thread)

These special nuts have “forward” right-hand thread on one side and “reverse” left-hand thread on the other side. The left thread side screws onto the valve, and the right thread side screws into the tank. This allows a screw-on valve to be tightened without the valve turning, and allows the valve to face any direction 360 degrees after tightening.

C20: 22 x 1 internal right to 22 x 1 internal left  turnbuckle nut   $7 chrome

C21: 16 x 1 internal right to 16 x 1 internal left  turnbuckle nut   $2

This turnbuckle type (LH and RH) nut is used on all 16mm female (internal-thread) moped gas valves.

C21a: 14 x 1 internal right to 14 x 1 internal left  turnbuckle nut   ??

C22: 12 x 1 internal right to 12 x 1 internal left  turnbuckle nut   $1

This turnbuckle type (LH and RH) nut is used on all 12mm female (internal-thread) moped gas valves. 

C23: 22 x 1 internal right to 16 x 1 internal left  turnbuckle nut   N/A

This new nut was made improperly. The 16 x 1 left thread ID is to big (so it would strip off the soft alloy threads of the petcock when fully tightened) and the center-line is not straight (so the sealing surface of the petcock is at an angle to the sealing surface of the tank).

C24: 16 x 1 internal right to 12 x 1 internal left  turnbuckle nut   N/A

There are two things to watch out for with these dual diameter dual thread nuts.

1. There are two ring-shape sealing surfaces on the petcock that must be close to the same height when the nut is fully tightened. The outer 

2. The ring-shape sealing surface on the gas tank must be wide enough to press against both of the petcock sealing surfaces.

Hoses and Parts

C29 clear nylon hose 3/16″ id 5/16″ od $1/foot fits moped spigots 5mm, no clamps

C30 soft aluminum tubing 1/8″ od $0.50/inch for making reserve tubes, longer or curved upward
continued easily bent, often must be ground slightly for press fit into hole

C31 “Y” connector for 3/16″  hose $3 for joining two fuel lines into one upward
continued for making a clear hose external fuel gauge, or for dual gas tanks

B1. 13 push-in (clamp-on) spigot right

B1 ∅13 push-in
spigot right  $25
made in Italy by OMG

Links to photos of examples:

1976 Vespa Bravo with plastic tank, original
2001 Tomos TX50 original
2003 Tomos MC50 original

This valve is for Vespa Bravos with plastic gas tanks (some 70’s European models and some 1976-77 US models), and for Tomos off-road models. Tomos #237248. It is all metal, well made, and not prone to breaking like the black plastic ones are.

B2. 15 push-in (clamp-on) spigot down

B2 ∅15 push-in
sp down 4180 $30

Links to photos of examples:

1983 Derbi Variant SLE original

This valve replaces side-mounted Derbi Variant valves. It’s a vertical valve, but on a Derbi it is in a horozontal position. Since there is no curved-up reserve tub, there is no reserve. An aluminum curved-up reserve tube is optional for $12 more.

B5. 12 push-in (clamp-on) spigot back

B5 ∅12 push-in
spigot back  N/A

Links to photos of examples:

1997-2000? DiBlasi R7E  folding mini-cycle #2024 spigot back, clamp #166

This B5 petcock #2024 was on  left side of 1997-00? DiBlasi R7E
Before that, A5  #141  was on  left side of 1989-97  DiBlasi R7TB
Before that, A5  #141  was on  left side of 1982-89  DiBlasi R7WT
Before that, A5  #141  was on  left side of 1979-82  DiBlasi R7ST
Before that, A3  #102 was on right side of 1974-79  DiBlasi R2

B6. 12 push-in (clamp-on) spigot right

B6 ∅12 push-in
spigot right  N/A

Links to photos of examples:

2001?-on DiBlasi R7E-V2  folding mini-cycle, #2091 spigot right, clamp #166

This B6 petcock #2091 was on left side of 2001?-on DiBlasi R7E-V2
Before that, B5 #2024 was on  left side of 1997-00? DiBlasi R7E
Before that, A5  #141  was on  left side of 1989-97  DiBlasi R7TB
Before that, A5  #141  was on  left side of 1982-89  DiBlasi R7WT
Before that, A5  #141  was on  left side of 1979-82  DiBlasi R7ST
Before that, A3  #102 was on right side of 1974-79  DiBlasi R2

B13. Bolt-on valve for Angel

B13 Angel sheet-frame  N/A
6 mm holes spaced 36 mm c-c

Links to photos of examples:

1973-74 Honda PM50 Novio/Canguro sheet-frame moped
1973-74 Honda PM50 Novio/Canguro sheet-frame moped
PM50 gas valve 16950-122-000 offered at cmsnl.com
1977 Angel AP48 (Honda PM50 remake)
1978 Angel AP48 (Honda PM50 remake)

This side-mount bolt-on valve is scarce and not available for sale. Only these two leaking used ones exist at Myrons Mopeds. This petcock uses a D2 inner seal disk. See below.

Son of Honda PM50: The 1977-79 Angel AP48, made in Taiwan by TYM, is a remake of a 1973-74 Honda PM50, made in Belgium. The PM50 was not sold in the US. Some are called Novio and some are Canguro. The name Novio was also on PF50, a completely different bike and engine. 

B15. Inline (Remote) valve for Trac

B15 632747 $28
↑reserve ←off on↓
made in Korea

Links to photos of examples:

1983-85 Trac Hawk (Laura M56 engine w/pedals) original
1983-85 Trac Clipper (Laura M56 engine w/pedals) original
1984-89 Trac Image (Daelim DK50 engine no pedals) original
1984-88 Trac Escot (Daelim DK50 engine no pedals) original
1986-86 Trac Hawk (Daelim DP50 engine w/pedals) original
1987-89 Trac Sprint (Daelim DP50 engine w/pedals) original
1986-89 Trac Clipper (Daelim DP50 engine w/pedals) original

More than half of these Korean made NOS gas valves have cracks or are broken. These are ones that have been inspected and tested.

This petcock uses a D2c inner seal disk, a D2 with the holes widened. See below.

B16. Inline (Remote) valve for Suzuki Shuttle

B16 Remote
valve  N/A

Links to photos of examples:

1982 Suzuki FA50 Shuttle original

This is for information, not for sale. None are available.

OMG front

OMG rear

Inner Seal Discs

These rubber disks are hard and deteriorated after 30 years. The rest of the petcock is metal and lasts forever, or has round seal rings that are relatively easy to find.

Cross Referencing Hopes: The sizes, applications, and possible sourcing of these vital rubber disks is being studied. It is hoped that some of the common moped gas valves might use the same rubber seal as some kinds of Honda, Kawasaki, Suzuki, Yamaha, or others. When that information becomes available, it will be posted here. Then anyone could order a seal disk for a small brand name bike from a big brand name parts supplier. 

Flipping: Old rubber inner seal disks get hard, shrink, and become deformed. Some can be flipped over to expose a fresh unused side.

Karkoma 16×1 spigot back with decomposed disk

Vintage Karcoma: Left, an actual original 1970’s Karkoma (Germany) gas valve from a 1979 Kynast moped, with only 50 miles of use. 30+ years of sitting with old, rotten gasoline premix has completely clogged the passageways with hard tar, and decomposed the seal disk to where it broke when the valve was disassembled. Part of the seal disk shaped like a smile broke off and stuck to the movable plate with handle. Usually when these get sticky the handle ends up getting snapped off, in addition to the seal disk crumbling and the holes clogged.  This is the kind that uses a 3.3mm tall lip on the outer edge of the 2.0mm tall by 13.7mm diameter seal disk D4. Later 1980’s Karkoma valves did not have the lip. For those the D4 early seal disk lip must be carefully ground off. Even the last few new old stock 1970’s Karkoma seal disks, once clear orange, now cloudy gold, are brittle and crack and crumble easily in your fingers. Too bad. That is why disk D4 is N/A not available.

Seal disks D1 to D6

Seal disk D8

D9 OMG seal disk 13.9 x 1.6
3 rings stick up from holes
they fit inside valve holes
to keep disk from rotating

 #  price  OD x thickness  style   Fuel Petcock Inner Seal Disks
D1x N/A    19.3 x 3.0  8 holes Honda 16115-001-004 60’s Cub
D2x $$8   16.3 x 3.0  4 holes Honda 16957-ZE1-812 replaces 16955-011-010, 16955-028-004
D2x $00   16.3 x  3.0 4 holes fits 60’s-70’s Honda’s and Trac Eagle (Korea), Angel (Taiwan)
D2a N/A    15.8 x 2.8  4 holes very shrunk D2 from ’65 Honda CA200
D2b N/A    16.2 x 2.8  4 holes shrunk D2
D2c $22   16.3 x 3.0  4 holes D2 with the 4 holes widened
D3x $$7   22.0 x 2.3  2+2 holes Piaggio 013836 vintage Vespa scooters
D4x N/A    13.7 x 2.0  3.3 outer lip, 70’s Karkoma (Germany)
D5x N/A    14.0 x 2.0  3 ∅3.5 holes 70’s Paioli for valve A33
D5a N/A    14.9 x 3.2  3 holes shrunk unknown
D6a N/A    13.4 x 2.3  3 holes shrunk aftermarket
D7x N/A    13.7 x 2.0  3 holes no outer lip, 80’s Karkoma (Germany)
D8x $12   18.8 x 3.1  3 holes blue Derbi (Spain) valve=18.5
D8a $$5   18.6 x 3.0  3 holes shrunk D8
D9x $13   13.9 x 1.6  3 holes 3 lips OMG (Italy) for most replacements
D10 $$9   20.4 x 3.3  4 holes Honda 16955-268-020 another view
D10 $$$   20.5 x 3.2  4 holes Indian (Taiwan) for valve A35
D11 N/A    22.3 x 3.5  4 holes General (Taiwan) for valve A28
D16 N/A    28.5 x 2.4  5 holes KL-18-6643 Kawasaki 11009-1194
D17 N/A    22.6 x 2.4  5 holes KL-18-6644 Kawasaki 11009-1188
D18 N/A    23.0 x 2.4  2 holes + slot KL-18-6645 Kawasaki 43049-1066
D19 N/A    18.8 x 2.4  4 holes KL-18-6646 Kawasaki 43049-1017
D21 N/A    00.0 x 0.0  Honda 17993
D22 N/A    00.0 x 0.0  Honda 16955-HA2-005  close up view
D24 N/A    00.0 x 0.0  Kawasaki 92065-094
D25 N/A    00.0 x 0.0  Kawasaki 92065-055
D26 N/A    00.0 x 0.0  Suzuki 44341-18450
D27 N/A    00.0 x 0.0  Suzuki 51455-010
D28 N/A    00.0 x 0.0  Yamaha 47X-24523-00
D29 N/A    00.0 x 0.0  Yamaha 137-24523-00

Seal disks D16 to D19:
These four KL Supply petcock inner seal disks have dozens of motorcycle and ATV applications, and hopefully some mopeds.

Valve A33 with disk D5

D5 seal disk

Vacuum Petcock

Fuel Valve (on tank): On or near the bottom of nearly every moped gas tank is a “petcock” or “gas valve” that has a lever or knob for manually shutting the fuel supply off, for when the bike is stored or transported. The reason for the shut off valve is gravity. Moped and most motorcycle gas tanks are higher than the engine and use gravity to move the gasoline out of the tank, instead of a fuel pump. The higher the liquid fuel level is above the carburetor, the higher the fuel pressure will be. If the the tank is too low, or the carb too high, no gas will come out, or it will even flow backwards. Everyone knows that liquids only flow downhill.

Vacuum Petcock (on tank): On most modern scooters and motorcycles the fuel valve is an automatic type, operated by the vacuum from the engine. When the engine stops, or whenever the suction in the vacuum line stops, the petcock shuts the gas off.

Float Valve (inside carb): In addition to the fuel valve, there is an second device, called the float needle or float valve, in the carburetor that shuts off the gas supply automatically. On a new bike with a new carburetor and clean gasoline, the float valve works all the time, so there is no need to turn the gas valve off after each use. On most old mopeds, the float valve leaks sometimes, and needs the operator to manually turn the gas valve off after each use to prevent gasoline from leaking out.

On-Off-Reserve: Besides turning the gas on and off, most gas valves also have a third position called “reserve”. Reserve is for when the tank is very low on gas. A little tube 1 or 2 inches long sticks up from the gas valve, inside the tank. When the gas is on “ON”, it exits from the upper end of the tube. When the level of gasoline drops below the tube, no more gas comes out, and the engine dies. This is called “hitting reserve”. The operator then switches the gas valve to “RESERVE”, which make the gas exit from the lower end of the reserve tube, at the very bottom of the gas tank. There is about 5 or 15 miles of gasoline available on reserve, enough to find a gas station. If a gas tank  has rust crumbs, powder, or water droplets at the very bottom, it is better to not use the reserve because it lets dirt get through and will clog easily.

Bolt-on petcock, 2-bolt

Bolt on petcock, 1-bolt

Fuel Valve Types

Bolt-on: Most modern motorcycles use the bolt-on design, where the tank has two small threaded 6mm bolt holes spaced about 30-35mm apart, with a 10mm main hole in the middle. A race track shaped rubber ring provides the seal. Angel (made in Taiwan by Tym) is the only pedal moped with a bolt on fuel valve. For some reason, bolt on fuel valves are rare on mopeds, but common on motorcycles.

Screw-on: Almost all mopeds use the screw-on design, where the tank has either a hole with internal threads, (female tank) or a fitting with external threads (male tank). Screw-on fuel valves do not seal at the threads like pipes, but rather have a sealing surface perpendicular to the threads, for a soft paper or plastic washer. They are tightened enough to compress the seal washer.

“Female” screw-on fuel valves for external thread tanks have the ability to point in any direction, because the valve main body does not screw on, instead only the nut turns. The special nut is a “turnbuckle style” in that it has right hand threads on one end and left hand threads on the other. This allows the valve to fit in tight places. It also means the nut has a top and bottom and won’t go on upside down, unlike a regular nut.

“Male” screw-on fuel valves for internal thread tanks also have the ability to point in any direction. When the seal washer is soft rubber and thick, and retained by a metal cup, it seals even when the valve is slightly loose and somewhat free to rotate.

Clamp-on: A third type of gas valve is clamp-on, found on Derbi mopeds with a plastic gas tank. It seals against the tank exit pipe semi-flexible soft plastic walls by o-rings squeezing radially inward by a hose clamp.

Spigot Direction:  L = left    R = right    D = down    B = back  (as you face the valve). Some models have room for more than one spigot direction. Many mopeds can have any spigot direction, because there is nothing near the petcock that interferes with the fuel hose. Then there may be choices. Other kinds are only available in one spigot direction. Sometimes an original valve that was “spigot down” must be replaced with one that is “spigot left”, and a longer piece of fuel line installed. Sometimes, if the valve is angled, and the spigot direction of the replacement valve is uphill, the new valve can affect fuel flow when the gas tank is really low. If it cannot be rotated and angled more spigot level or downwards, then the lower part of the tank will become unavailable when the liquid level reaches the highest part of the fuel line. That is, it will run out of gas prematurely.

Naming of Gas Valves: Many screw-on gas valves sold online are named by their true size (11,13, or 15mm), rather than their nominal size (12, 14, 16mm). This is a big source of confusion. For a bolt (external or male thread) the nominal (named) size is the true size, so an M6 (metric 6mm) bolt has a diameter of 6mm. But for a nut (internal or female thread), the nominal size is greater than the true size. An M6x1 nut has an internal diameter of 5mm. A 1/4 -20″ nut has an internal diameter of 0.20 inch, not 0.25. The difference between the external and internal diameter is approximately equal to the thread pitch. So a 12×1.00 nut measures 11.00mm inner diameter, while a 12×1.50 nut measures 10.5mm.

Gas valve low cost substitutes:  USA plumbers will recognize that the moped gas valve M10x1 thread is close to 1/8″ (named after the small inner diameter) National Pipe Thread Taper NPT . Because of the taper, a brass 1/8″ NPT (27tpi = 0.94mm) screws on and fits the 10×1 thread OK, because it’s about 9.5mm at first, tapering to 10.2mm. With teflon pipe thread tape, any 10×1 thread gas tank can be adapted with American standard pipe pieces, including shut-off valves. All of those things are sold in home improvement stores nationwide. The good side is those pipe pieces are inexpensive and easy to get. The bad side is they must be cleaned up and re-taped every time they are screwed on and off, and they don’t have any reserve feature. 

Gas valve outer seals: Screw on gas valves, unlike plumbing pipes, seal by a soft or semi soft ring, that is squeezed between the gas tank and the gas valve, as the valve or nut is screwed on tight. Plumbing pipes seal by the threads only, and don’t need a flange and soft ring. The sealing surface on both the tank and the valve must be flat and straight. If a gas tank has a damaged sealing surface, then the outer seal might leak, even when the seal and valve are fine. The remedy for a warped, misaligned or scratched sealing surface, on either the tank or the valve, is careful grinding with a flat spinning disk (with all gasoline evacuated).