50cc pistons for sale here are listed by “pin”, the wrist pin thickness, and “upper”, the distance from the pin edge to the top edge. Pin ranges from 10 to 14mm. Upper ranges from 13 to 23mm.
Pistons in the same section have the same upper and pin dimensions, and so can potentially interchange, if the bore and maybe other things are the same. That is why pistons are listed by size rather than name.
For example, an oversize Peugeot 103 piston 40.5mm is perfect for a worn 40.4mm Morini MO1, after honing. They are both 12 pin and 16 upper, in the 12-16 section.
Look up or measure your piston’s pin size and upper length,
then scroll to that “pin-upper” section.
pin-upper
12-18 Batavus with Laura M48 engine
12-17 Benelli 1965-1980
12-23 Casal K177, others
10-19 Columbia with Solo 255 engine
12-22 Columbia with Sachs 505 engine
12-18 Daelim DP50, DK50 engine
12-22 Demm Smily
12-17 Derbi Variant, TT, RD50 1974-1986
12-18 Derbi Variant Sport 1986-90
14-24 Flandria Bermuda
12-18 Garelli Eureka, Noi, Gulp, VIP
12-22 Garelli Monza GT
12-16 Hero Majestic mid-90’s
10-20 Honda NC50, NA50, NU50, PA50
12-19 Honda NS50F
13-13 Indian AMI50 with PC50K1 re-make engine
14-18 Jawa Babetta 207 1970-83
12-16 Kawasaki AR50
12-20 Kinetic TFR with Piaggio re-make engine
12-19 Kreidler MP9, MP19
12-18 Laura M48, M56 engine
12-21 Minarelli V1L, V1HL engine
12-22 Minarelli V1, V1H engine
12-16 Morini MO1 MO2 MO4 M1 M101 w/alum fins
12-19 Morini MO1, MO2, M1 with iron cylinder fins
12-22 Morini S5K, S5K2, S5R, S5T engine
13-15 Motobecane 40, 50 with AV7 engine
10-19 Odyssey with Solo 254, 255 engine
12-16 Peugeot 102, 103 series
10-18 Puch MS50, others 50’s-60’s
12-17 Puch Maxi, others 1969-86
12-15 Rizzato 119 engine on Califfo
12-22 Sachs 504, 505 engine
10-18 Sears Allstate moped and early Puch
10-19 Solo 236, 237, 254, 255 engine
12-21 Suzuki FA50 Shuttle, FY50, FZ50
10-18 Tomos A3 engine 1974-91
12-17 Tomos A35 engine 1992-2006 (cyl says A5)
12-17 Tomos A55 engine 2002-18 (case says A52)
12-18 Trac 1981-96 with M56-remake engine
10-19 TYM M48-remake engine on Angel, Speed Bird
12-20 Vespa (Piaggio) Ciao, Bravo, Grande, Si
10-21 Vespa (Piaggio) Ciao, Si (1990’s Euro)
10-20 Yamaha QT50 Yamahopper, PW50
updated 2021-03
Notes:
Piston actual diameter is measured at skirt (bottom), where it is largest.
All new pistons come with new rings, clips and pin, unless noted.
gap GN grano normale means side pin gap style (aka FG foro grano)
gap GI grano interno means center pin gap style (see photos above)
Meanings: “size” = cylinder bore
ring c1.5n means common (rectangular), 1.5mm thick, normal gap style
ring c1.5i means common (rectangular), 1.5mm thick, internal gap style
ring t1.5n means trapezoidal (slanted top) 1.5mm outer, normal gap style
ring t1.5i means trapezoidal (slanted top) 1.5mm outer, internal gap style
ring L1.5 means “L“-shaped (aka Dykes), 1.5mm outer, L-ring gap style
“x” means that part of the number is unknown
Tom. A3
10-18 pistons for 1974-91 Tomos A3, 50’s-60’s Puch and Tomos
pin up lo bore M# skirt ring1 ring2 price maker 38.0 bore, 10 pin, 18 upper
10-18-24-38.00-0 37.94 c2.0n c2.0n n.a. Mahle 2074?? Tomos A3 1.0hp
10-18-24-38.00-0 37.94 c2.0n c2.0n n.a. 55 tall, 52 at edge = 24+10+18
10-18-21-38.00-0 37.94 c2.0n c2.0n n.a. Mahle 207407 Tomos A3 1.5hp
10-18-21-38.00-0 37.94 c2.0n c2.0n n.a. 52 tall, 49 at edge = 21+10+18
’60’s Puch
10-18-19-38.00-0 37.94 c2.0n c2.0n $50 Mahle 207403 Tomos A3 2.0hp
10-18-19-38.00-0 37.94 c2.0n c2.0n $00 50 tall, 47 at edge = 19+10+18
10-18-19-38.00-1 37.95 c1.5n c1.5n $60 generic for Tomos A3
10-18-18-38.00-0 37.95 c2.0n c2.0n n.a. generic for Tomos A3
10-18-00-38.00-0 37.9x c2.5n c2.5n n.a. Mahle 0501.1006.2 Sears Allstate
pin up lo bore M# skirt ring1 ring2 price maker 38.5 bore, 10 pin, 18 upper
10-18-19-38.50-0 38.45 c2.0n c2.0n n.a. Mahle 202420 Tomos A3 oversize
Tomos+Solo
10-19 pistons for 1976-80 Solo on Odyssey,Columbia, ’77-84 TYM Angel
pin up lo bore M# skirt ring1 ring2 price maker 38.0 bore, 10 pin, 19 upper
10-19-22-38.00-N 37.9x c1.5n c1.5n n.a. Mahle 2200593 Solo piston “N”
10-19-22-38.00-U 37.9x c1.5n c1.5n n.a. Mahle 2200600 Solo piston “U”
pin up lo bore M# skirt ring1 ring2 price maker 40.0 bore, 10 pin, 19 upper
10-19-15-40.00-0 39.92 c1.5n c1.5n n.a. generic original Angel/Speed Bird
Angel+Batavus
A Batavus piston (12 x 33 mm pin) can substitute for an Angel piston (10 x 33 pin), if the piston pin needle bearing is changed. The 10x14x13 needle bearing (with 2mm rollers) needs to be 12x14x13. But there are none that thin (1mm rollers). So a bronze bushing 12x14x13 must be used instead of a needle bearing, like one from a Puch. There are already oil holes in the Angel rod. Those holes need to extend through the bronze bushing to oil the pin.
NC50
QT50
10-20 pistons for 1977-83 Honda NC50 PA50, Yamaha QT50 PW50
pin up lo bore M# skirt ring1 ring2 maker price 40.0 bore, 10 pin, 20.5 upper
10-20-18-40.00-0 39.95 t1.5n c1.5n Honda n.a. 13101.147.000 Honda NC50
10-20-18-40.00-0 39.95 t1.5n c1.5n Honda n.a. Honda PA50 (has decomp cut)
10-20-18-40.00-1 39.95 t1.5n c1.5n generic $43 re-make Honda NC50, PA50
10-20-17-40.00-0 39.9x t1.5n c1.5n Yamaha n.a. 3L5.11630.00.00 Yamaha QT50, PW50
Vespa
Eton
10-21 pistons for 1990’s Vespa (Euro), China scooters
pin up lo bore M# skirt ring1 ring2 maker price 38.2 bore, 10 pin, 21 upper
10-21-17-38.20-0 38.13 L2.0n c1.5n Meteor $60 Vespa 84-85 Ciao & Si, Euro models
pin up lo bore M# skirt ring1 ring2 maker price 40.0 bore, 10 pin, 21 upper
10-21-18-40.00-0 39.9x t1.2n t1.2n generic $60 632964 E-Ton 50cc 2-stroke scooter
pin up lo bore M# skirt ring1 ring2 maker price 40.25 bore, 10 pin, 21 upper
10-21-18-40.25-0 40.1x t1.2n t1.2n generic $60 632965 1os E-Ton 50cc 2-stroke scooter
Rizzato
12-15 pistons for Rizzato 119 engine on Califfo, Atala
pin up lo bore M# skirt ring1 ring2 maker price 39.4 bore, 12 pin, 15 upper
12-15-23-39.40-0 39.33 c2.5n c2.5n generic $45 original no rings, none available
pin up lo bore M# skirt ring1 ring2 maker price 39.8 bore, 12 pin, 15 upper
12-15-23-39.80-0 39.73 c2.5n c2.5n generic $65 original 1os Rizzato Califfo
This is an unusual design from the 1950’s, with the highest wrist pin. That allows transfer flow through the lower part of the piston, instead of around the sides completely. The top crown of the piston is a normal shallow dome, but with three equal large “bites” taken out of it.
Peugeot+Morini
12-16 pistons for ’70’s Peugeot 103, 102, others, ’90’s Hero
and ’72-80 Morini MO, MO1, MO2, M1, M101 with aluminum cylinder fins
pin up lo bore M# skirt ring1 ring2 maker price 39.0 bore, 12 pin, 16 upper
12-16-18-39.00-0 38.95 t1.2n t1.2n generic n.a. 13001.1074 Kawasaki AR50
pin up lo bore M# skirt ring1 ring2 maker price 40.0 bore, 12 pin, 16 upper
12-16-17-39.91-A 39.88 c2.5i c2.5i Peugeot $70 69707 Peugeot Sort A
12-16-17-39.92-B 39.89 c2.5i c2.5i Peugeot $70 69708 Peugeot Sort B
Peugeot
12-16-17-39.93-C 39.90 c2.5i c2.5i Peugeot $70 69709 Peugeot Sort C (=AA)
12-16-17-39.94-D 39.91 c2.5i c2.5i Peugeot n.a. 69710 Peugeot Sort D (=BB)
12-16-17-39.94-0 39.91 c2.5i c2.5i GOL $60 replica Peugeot Sort D (=BB)
12-16-17-40.00-0 39.92 c1.5i c1.5i Asso 00 n.a. 23-01xx Morini early MO1 cut=3
12-16-17-40.00-1 39.9x c2.0n c2.0n generic n.a. original Hero Pacer, Panther
12-16-17-39.95-E 39.92 c2.5i c2.5i Peugeot $70 69711 Peugeot Sort E (=CC)
12-16-17-39.96-F 39.93 c2.5i c2.5i Peugeot $70 69712 Peugeot Sort F (=DD)
1995 Hero Panther
12-16-17-39.96-0 39.93 c1.5i c2.5i generic $70 re-make MMI MF553-F for Peugeot
12-16-17-39.97-G 39.94 c2.5i c2.5i Peugeot $70 69713 Peugeot Sort G (=EE)
12-16-17-39.98-H 39.95 c2.5i c2.5i Peugeot $70 69714 Peugeot Sort H (=FF)
12-16-17-39.98-0 39.95 c2.5i c1.5i generic $70 re-make MMI MF553-C for Peugeot
12-16-17-39.99-I 39.96 c2.5i c2.5i Peugeot n.a. 69715 Peugeot Sort I (=GG)
12-16-17-40.00-J 39.97 c2.5i c2.5i Peugeot n.a. 69715a Peugeot Sort HH
12-16-17-40.01-ii 39.98 c2.5i c2.5i Peugeot n.a. 69715b Peugeot Sort II
pin up lo bore M# skirt ring1 ring2 maker price 40.4 bore, 12 pin, 16 upper
12-16-17-40.40-L 40.33 L2.0 c1.5i Asso n.a. 23.01?? Morini MO4 cut=3 ASSO 1929MO4
12-16-17-40.40-0 40.35 c1.5i c1.5i Asso $70 23.0125 Morini MO1,2 cut=5 ASSO.W 2351
12-16-17-40.40-0 40.32 c1.5i c1.5i Asso n.a. 23.0125 Morini MO1,2 cut=3 ASSO 1929
12-16-17-40.40-0 40.31 c1.5i c1.5i generic n.a. 23.0125 Morini MO1,2 cut=3 says nothing
12-16-17-40.40-0 40.32 c1.5i c1.5i Asso n.a. 23.0125 Morini MO1,2 cut=3 ASSO.W 2352
12-16-17-40.40-1 40.32 c1.5i c1.5i Meteor $60 23.0134 Morini M1 cut=0
12-16-17-40.40-1 40.32 c1.5i c1.5i Asso n.a. 23.0134 Morini M1 cut=0 ASSO W 1929M1
Morini pistons
pin up lo bore M# skirt ring1 ring2 maker price 40.5 bore, 12 pin, 16 upper
12-16-17-40.47-K 40.44 c2.5i c2.5i Peugeot $60 69716 1os Peugeot Sort K
12-16-17-40.48-L 40.45 c2.5i c2.5i Peugeot $60 69717 1os Peugeot Sort L
12-16-17-40.49-M 40.46 c2.5i c2.5i Peugeot $60 69718 1os Peugeot Sort M
12-16-17-40.50-N 40.47 c2.5i c2.5i Peugeot $60 69719 1os Peugeot Sort N
12-16-17-40.51-P 40.48 c2.5i c2.5i Peugeot $60 69720 1os Peugeot Sort P
12-16-17-40.52-Q 40.49 c2.5i c2.5i Peugeot $60 69721 1os Peugeot Sort Q
pin up lo bore M# skirt ring1 ring2 maker price 40.6 bore, 12 pin, 16 upper
12-16-17-40.60-0 40.53 c1.5i c1.5i Asso $72 23.0126/6 1os Morini MO1,2 cut=3 ASSO 1929
12-16-17-40.60-1 40.5x c1.5i c1.5i Asso n.a. 23.0135/6 1os Morini M1 cut=0 ASSO W 1929M1
pin up lo bore M# skirt ring1 ring2 maker price 40.8 bore, 12 pin, 16 upper
12-16-17-40.80-0 40.72 c1.5i c1.5i Asso $72 23.0126/8 2os Morini MO1,2 cut=3 ASSO 1929
12-16-17-40.80-1 40.7x c1.5i c1.5i Asso n.a. 23.0135/8 2os Morini M1 cut=0 ASSO W 1929M1
pin up lo bore M# skirt ring1 ring2 maker price 41.0 bore, 12 pin, 16 upper
12-16-17-41.00-0 40.90 c1.5i c1.5i generic $74 23.0126/0 3os Morini MO1,2 cut=3 says nothing
Morini MO1 and MO2 pistons have a cut-out on the bottom intake side. It can be different heights 0, 3 or 5 mm. That’s what “cut=3” means. Inside the piston is an ID mark, such as “ASSO 1929”. This can tell the piston type but not the size.
Peugeot 103 pistons have slightly different sizes, aka “sorts”.
Left of the red line are the “standard” 40.0mm sorts A to II (39.88-39.98).
Right of the red line are the “oversize” 40.5mm sorts K to Q (40.45-40.50).
Upper half are chrome bore cylinders, pre-1979 with single letter sorts A to Q.
Lower half are nikasil bore cylinders, 1979-on with double letter sorts AA to II.
Peugeot 103 moped pistons are a very old design that has been in use at least since the 1950’s. The rings are thick, 2.5mm, like most old rings were. Peugeot 103 cylinders are all aluminum with a chrome plated (pre-1979) or nikasil plated (1979-on) cylinder wall. They expand along with the aluminum piston as they get hotter. Unlike a steel sleeve cylinder that fits slightly loose, when cold, and wiggles a tiny bit, these should be a light sliding fit, where the piston, without rings, pushes through by hand but does not fall through by it’s own weight. When the piston fit is too loose, it makes a tinkle sound when idling, and produces less torque. When it’s too tight, it simply won’t move easy, or at all, and when hot it will smear (melt off) the hot exhaust side and stick (seize). The procedure for “fitting” a Peugeot piston requires a flat stone cylinder hone (not a ball hone) for first making the cylinder wall flat by removing any high spots, and a Dremmel high speed rotary cutting tool for removing burrs from the edges of the ports, and a small round file for removing burrs and high spots from the piston, especially around the wrist pin holes. Sometimes just the act of pushing the wrist pin in and out will raise the corner edge and make the piston fit tighter. The bare piston is pushed into the cylinder in different ways. The high spots are located, by feel and sometimes vision, and removed. When all high spots are removed, and the piston still does not fall through under it’s own weight, then the fit is perfect. Worn cylinders need slightly bigger pistons. So a worn “C” cylinder might need a D, E, or F piston. Badly worn or “gouged” cylinders need to be replaced (unless the gouges are lower than the exhaust port). Peugeot has made plenty of “oversize” (40.5mm instead of 40.0mm) pistons. But there are no 40.5 cylinders in California, only 40.0mm. That’s why Myrons Mopeds has 40.5 pistons but no cylinders. Too bad it’s expensive to bore out and re-plate a nikasil cylinder. It is an option, made possible by the half millimeter bigger pistons available.
Tomos A55
12-17 pistons for ’69-86 Puch, 91-18 Tomos, 74-86 Derbi, 65-80 Benelli
pin up lo bore M# skirt ring1 ring2 maker price 36.5 bore, 12 pin, 17 upper
12-17-18-36.50-0 36.43 c1.5n c1.5n Vertex $55 229803 Tomos MC36 36cc off road
pin up lo bore M# skirt ring1 ring2 maker price 38.0 bore, 12 pin, 17 upper
12-17-18-38.00-0 37.93 c2.0n c2.0n generic $40 406300 Puch Step II, made small
12-17-18-38.00-A 37.95 c1.5n c1.5n generic n.a. 409000 Tomos A35 iron cyl, has windows
Tomos A35
12-17-18-38.00-B 37.95 c1.5n c1.5n Vertex $65 223747 Tomos A35 has windows on int. side
12-17-19-38.00-0 37.91 c2.0n c2.0n generic $30 406300 Puch early 2000’s, way small
12-17-20-38.00-0 37.96 c1.5n c1.5n generic $55 thereal1 Puch, well-made in Taiwan
12-17-21-37.99-0 37.95 c2.0n none Mahle $72 original Puch ’84 alu sort C 38 C 1734
12-17-21-37.98-1 37.95 c2.0n c2.0n Mahle n.a. 349.110.0069/21 Puch alu cyl sort 1 38 1 101
12-17-21-37.99-2 37.96 c2.0n c2.0n Mahle n.a. 349.110.0069/22 Puch alu sort 2 38 2 1019
12-17-21-38.00-3 37.97 c2.0n c2.0n Mahle n.a. 349.110.0069/23 Puch alu sort 3 38 3 1019
12-17-21-38.01-4 37.98 c2.0n c2.0n Mahle $65 349.110.0069/24 Puch alu sort 4 38 4 1019
12-17-21-38.02-5 37.99 c2.0n c2.0n Mahle $75 349.110.0069/25 Puch alu sort 5 38 5 1019
Puch
12-17-21-37.98-A 37.95 t1.5n t1.5n Vertex n.a. 233709 Tomos A55 alu cyl to-’06 trap. rings
12-17-21-37.98-B 37.95 c1.5n c1.5n Vertex $65 233709 Tomos A55 alu cyl ’07-on 14140 37.98
12-17-22-38.00-1 37.95 c2.0n c2.0n Mahle n.a. 350.310.0069/03 Puch HT sort 11 38 1 1116
12-17-22-38.01-2 37.96 c2.0n c2.0n Mahle n.a. 350.310.0069/04 Puch HT sort 22 38 2 1116
12-17-23-38.00-C 37.94 c2.0n c2.0n GOL $60 0037A-C Puch, made in Italy by GOL
12-17-23-38.00-D 37.95 c2.0n c2.0n GOL $60 0037A-D Puch, made in Italy by GOL
12-17-23-38.00-0 37.95 L2.0 c1.5n Mahle $70 000.802.5090 Derbi 1976-86 says B9
12-17-23-38.00-1 37.95 L2.0n c2.0n Mahle n.a. 349.210.5069/11 Puch HT 11 38.0 11 1593a
12-17-23-38.01-2 37.96 L2.0n c2.0n Mahle n.a. 349.210.5069/22 Puch HT 22 38.0 22 1593a
12-17-23-38.02-3 37.97 L2.0n c2.0n Mahle $65 349.210.5069/33 Puch HT 33 38.0 33 1593a
Derbi-’86
pin up lo bore M# skirt ring1 ring2 maker price 38.25 bore, 12 pin, 17 upper
12-17-20-38.25-0 38.18 L2.0n c1.5n Mahle $40 000.802.5091 1os Derbi 76-86 0.25 B or 0.25 C
12-17-20-38.25-ll 38.18 L2.0n L2.0n Mahle $40 000.802.5091 1os same but both L-rings!
12-17-20-38.25-0 38.18 L2.0n c1.5n Mahle $35 000.802.5091 1os Derbi 76-86 38.205 JG 0.045
12-17-23-38.25-1 38.19 L2.0n c2.0n Mahle $75 349.310.4669/03 1os Puch 11 38.25 11 1593a
12-17-23-38.25-2 38.20 L2.0n c2.0n Mahle $75 349.310.4669/04 1os Puch 22 38.25 22 1593a
pin up lo bore M# skirt ring1 ring2 maker price 38.4 bore, 12 pin, 17 upper
12-17-20-38.40-0 38.3? L2.0n c1.5n Mahle n.a. 000.802.5092 2os Derbi 1976-1986
pin up lo bore M# skirt ring1 ring2 maker price 38.5 bore, 12 pin, 17 upper
12-17-21-38.50-0 38.4x c1.5n c1.5n Vertex n.a. 227334 1os Tomos A35
12-17-21-38.50-1 38.4x c1.5n c1.5n generic $60 409001 1os Tomos A35
pin up lo bore M# skirt ring1 ring2 maker price 38.7 bore, 12 pin, 17 upper
12-17-20-38.70-0 38.6x L2.0n c1.5n Mahle n.a. 000.802.5093 3os Derbi 1976-1986
pin up lo bore M# skirt ring1 ring2 maker price 38.9 bore, 12 pin, 17 upper
12-17-20-38.90-0 38.8x L2.0n c1.5n Mahle n.a. 000.802.5094 4os Derbi 1976-1986
Benelli
pin up lo bore M# skirt ring1 ring2 maker price 40.0 bore, 12 pin, 17 upper
12-17-18-40.00-0 39.9x c1.5n c1.5n Asso n.a. 70.06.04.00 Benelli ’65-80 #G7346
12-17-18-40.00-1 39.95 c1.5n c1.5n GOL $65 70.06.04.00a Benelli ’65-80
12-17-19-40.00-0 39.94 t1.5n t1.5n Yamaha $60 original Yamaha model? complete
pin up lo bore M# skirt ring1 ring2 maker price 40.2 bore, 12 pin, 17 upper
12-17-18-40.20-0 40.1x c1.5n c1.5n Asso n.a. 70.06.04.02 1os Benelli ’65-80 #G7346/2
pin up lo bore M# skirt ring1 ring2 maker price 40.25 bore, 12 pin, 17 upper
12-17-19-40.25-0 40.22 t1.5n t1.5n Yamaha $30 original 1os Yamaha model? without rings
pin up lo bore M# skirt ring1 ring2 maker price 40.4 bore, 12 pin, 17 upper
12-17-18-40.40-0 40.3x c1.5n c1.5n Asso n.a. 70.06.04.04 2os Benelli ’65-80 #G7346/4
Daelim
12-18 pistons for 86-89 Derbi, 70-90 Garelli, 72-80 Batavus, 81-89 Trac
pin up lo bore M# skirt ring1 ring2 maker price 40.0 bore, 12 pin, 18 upper
12-18-14-40.00-T 39.9x t1.5n t1.5n generic n.a. ?????? Daelim (Trac) original (trap. rings)
12-18-14-40.00-0 39.95 c1.5n c1.5n Mahle n.a. 480580 Batavus M48 original says 39.95
12-18-14-40.00-1 39.92 c1.5n c1.5n generic $70 408211 Daelim (Trac) replica (rect. rings)
12-18-14-39.99-A 39.96 c1.5n c1.5n Mahle n.a. 80016 Batavus/Trac M56 original Sort A
12-18-14-40.00-B 39.97 c1.5n c1.5n Mahle n.a. 80017 Batavus/Trac M56 original Sort B
12-18-14-40.01-C 39.98 c1.5n c1.5n Mahle n.a. 80018 Batavus/Trac M56 original Sort C
Batavus
12-18-14-40.02-D 39.99 c1.5n c1.5n Mahle n.a. 80019 Batavus/Trac M56 original Sort D
12-18-14-40.03-E 40.00 c1.5n c1.5n Mahle n.a. 80020 Batavus/Trac M56 original Sort E
12-18-14-40.00-F 40.0x c1.5n c1.5n Mahle n.a. ?????? Batavus/Trac M56 original Sort F
12-18-16-40.00-0 39.93 c2.0n c2.0n generic $60 Treats Garelli/Batavus aftermarket
12-18-16-40.00-1 39.95 c2.0n c2.0n GOL $60 0037 Garelli/Batavus aftermarket
12-18-16-40.00-0 39.9x c2.0n c2.0n Asso n.a. 200001.2.150 Garelli iron cylinder 20,30mph
12-18-?? -40.00-0 39.9x c2.0n c2.0n Asso n.a. 205058.2.150 flat top, Garelli al cyl 20,25mph
12-18-?? -40.00-0 39.9x c2.0n c2.0n Asso n.a. 205088.2.150 flat top, Garelli alu cyl 30mph
12-18-17-40.00-0 39.9x c2.0n c2.0n Asso n.a. 205053.2.150 Garelli iron cylinder 25mph
12-18-19-39.97-A 39.945c1.5i c1.5i Mahle n.a. 0F0.250.0091/A Derbi ’86-89 flat reed, sort A
12-18-19-39.97-B 39.950c1.5i c1.5i Mahle n.a. 0F0.250.0091/B Derbi ’86-89 flat reed, sort B
12-18-19-39.98-C 39.955c1.5i c1.5i Mahle n.a. 0F0.250.0091/C Derbi ’86-89 flat reed, sort C
12-18-19-39.98-D 39.960c1.5i c1.5i Mahle n.a. 0F0.250.0091/D Derbi ’86-89 flat reed, sort D
12-18-19-39.99-E 39.965c1.5i c1.5i Mahle n.a. 0F0.250.0091/E Derbi ’86-89 flat reed, sort E
Garelli
pin up lo bore M# skirt ring1 ring2 maker price 40.2 bore, 12 pin, 18 upper
12-18-16-40.20-0 40.1x c2.0n c2.0n Asso n.a. 200001.2.151 1os Garelli iron cylinder 20, 30mph
12-18-17-40.20-0 40.1x c2.0n c2.0n Asso n.a. 205053.2.151 1os Garelli iron cylinder 25mph
pin up lo bore M# skirt ring1 ring2 maker price 40.25 bore, 12 pin, 18 upper
12-18-14-40.25-0 40.20 c1.5n c1.5n Mahle $75 480581 1os Batavus with Laura M48 engine
pin up lo bore M# skirt ring1 ring2 maker price 40.40 bore, 12 pin, 18 upper
12-18-16-40.40-0 40.3x c2.0n c2.0n Asso n.a. 200001.2.152 2os Garelli iron cylinder 20, 30mph
12-18-17-40.40-0 40.3x c2.0n c2.0n Asso n.a. 205053.2.152 2os Garelli iron cylinder 25mph
12-18-17-40.40-0 40.33 c2.0n c2.0n GOL $55 534404 2os Garelli (made in Italy)
pin up lo bore M# skirt ring1 ring2 maker price 40.60 bore, 12 pin, 18 upper
12-18-16-40.60-0 40.5x c2.0n c2.0n Asso n.a. 200001.2.153 3os Garelli iron cylinder 20, 30mph
12-18-17-40.60-0 40.5x c2.0n c2.0n Asso n.a. 205053.2.153 3os Garelli iron cylinder 25mph
pin up lo bore M# skirt ring1 ring2 maker price 40.80 bore, 12 pin, 18 upper
12-18-16-40.80-0 40.7x c2.0n c2.0n Asso n.a. 200001.2.154 4os Garelli iron cylinder 20, 30mph
12-18-17-40.80-0 40.7x c2.0n c2.0n Asso n.a. 205053.2.154 4os Garelli iron cylinder 25mph
Garelli pistons
Garelli 4th oversize 40.8mm piston, made by Asso, says “40.8”. You can see it’s bigger. Middle, Garelli standard 40.0mm piston, made by Asso, says “40” and “S”. The “S” means scoria, Italian for exhaust. Right, Garelli standard 40.0mm piston, aftermarket. All three are oriented with the exhaust side down, like in the engine.
Kreidler
12-19 pistons for 1970’s Kreidler Flory, 1990 Honda NS50
and ’75-80 Morini MO, MO1, MO2, M1 with all-iron cylinder fins
pin up lo bore M# skirt ring1 ring2 maker price 39.0 bore, 12 pin, 19 upper
12-19-16-39.00-0 38.94 t1.2n c1.2n generic none 13101-GE2-305 Honda NS50 ’90
pin up lo bore M# skirt ring1 ring2 maker price 39.25 bore, 12 pin, 19 upper
12-19-16-39.25-0 39.19 t1.2n c1.2n generic none 13102-GE2-305 1os Honda NS50 ’90
pin up lo bore M# skirt ring1 ring2 maker price 39.5 bore, 12 pin, 19 upper
12-19-16-39.50-0 39.44 t1.2n c1.2n generic none 13103-GE2-305 2os Honda NS50 ’90
pin up lo bore M# skirt ring1 ring2 maker price 39.75 bore, 12 pin, 19 upper
12-19-16-39.75-0 39.69 t1.2n c1.2n generic none 13104-GE2-305 3os Honda NS50 ’90
pin up lo bore M# skirt ring1 ring2 maker price 40.0 bore, 12 pin, 19 upper
12-19-15-39.98-D 39.93 c1.5i c1.5i Mahle $80 2150383d Kreidler Flory al cyl D R021 40154+
12-19-15-39.99-E 39.96 c1.5i c1.5i Mahle none 2150383f Kreidler Flory al cyl F R021 40154+
12-19-15-40.00-H 39.73 c1.5i c1.5i Mahle $60 2150383h (worn used) al cyl H R021 40154+
12-19-15-40.01-M 39.98 c1.5i c1.5i Mahle none 2150383m Kreidler Flo. al cyl M R021 40154
pin up lo bore M# skirt ring1 ring2 maker price 40.4 bore, 12 pin, 19.5 upper
12-19-17-40.40-0 40.32 c1.5i c1.5i Asso n.a. 23.0130 Morini MO1, MO2 all-iron cyl Asso 2139
12-19-17-40.40-1 40.3x c1.5i c1.5i Asso n.a. 23.0136 Morini M1 (reed) with all-iron cylinder
pin up lo bore M# skirt ring1 ring2 maker price 40.6 bore, 12 pin, 19.5 upper
12-19-17-40.60-0 40.5x c1.5i c1.5i Asso n.a. 23.0131/6 1os Morini MO1, MO2 all-iron cyl Asso 2139
12-19-17-40.60-1 40.5x c1.5i c1.5i Asso n.a. 23.0137/6 1os Morini M1 with all-iron cylinder
pin up lo bore M# skirt ring1 ring2 maker price 40.8 bore, 12 pin, 19.5 upper
12-19-17-40.80-0 40.7x c1.5i c1.5i Asso n.a. 23.0131/8 2os Morini MO1, MO2 all-iron cyl Asso 2139
12-19-17-40.80-1 40.7x c1.5i c1.5i Asso n.a. 23.0137/8 2os Morini M1 with all-iron cylinder
38.2 Vespa
12-20 pistons for Vespa (Piaggio), 1995-05 Kinetic TFR
Abbreviations: C is Ciao, B is Bravo, G is Grande, S is Si
pin up lo bore M# skirt ring1 ring2 maker price 38.2 bore, 12 pin, 20 upper
12-20-16-38.20-0 38.12 c2.0n c2.0n Piaggio $60 182591 Vespa US ’78-80 C B G says USA
12-20-16-38.20-1 38.1x L2.0n c1.5n Piaggio n.a. 191034 Vespa US ’79-86 Si, ’80-86 C B G
12-20-16-38.20-2 38.12 L2.0n c1.5n Asso $60 3517 replacement for above
38.4 Vespa
pin up lo bore M# skirt ring1 ring2 maker price 38.4 bore, 12 pin, 20 upper
12-20-16-38.40-K 38.30 t1.5n t1.5n generic n.a. Kinetic ’95-05 (Vespa remake) no arrow
12-20-16-38.40-0 38.3x c2.0n c2.0n Piaggio n.a. 112979 = 132521 Vespa ’67-76 Ciao, Boxer
12-20-16-38.40-1 38.32 c2.0n c2.0n Piaggio $50 132521 Vespa US ’76-78 Ciao, ’77-78 Bravo
12-20-16-38.40-2 38.32 L2.0n c1.5n Piaggio $65 182592 1os Vespa US ’78-86 C B G S says 1M
pin up lo bore M# skirt ring1 ring2 maker price 38.6 bore, 12 pin, 20 upper
12-20-16-38.60-0 38.54 c2.0n c2.0n Piaggio n.a. 152381 = 137681 1os Vespa ’67-76 C, Boxer
12-20-16-38.60-1 38.54 L2.0n c2.0n Piaggio n.a. 137681 1os Vespa US ’76-78 C B says 1M
12-20-16-38.60-2 38.5x L2.0n c1.5n Piaggio n.a. 182593 2os Vespa US ’78-86 C B G S says 2M
USA piston
& cylinder
pin up lo bore M# skirt ring1 ring2 maker price 38.8 bore, 12 pin, 20 upper
12-20-16-38.60-0 38.74 c2.0n c2.0n Piaggio $60 152382 = 137682 2os Vespa ’67-76 C, Boxer
12-20-16-38.60-1 38.74 L2.0n c1.5n Piaggio $60 137682 2os Vespa US ’76-78 C B says 2M
pin up lo bore M# skirt ring1 ring2 maker price 39.6 bore, 12 pin, 20 upper
12-20-16-38.60-0 39.47 L2.0n c1.5n Asso $48 3517 oversize for Vespa made in Italy
pin up lo bore M# skirt ring1 ring2 maker price 40.0 bore, 12 pin, 20 upper
12-20-17-40.00-0 39.9x t1.2n t1.2n generic $60 633992 China 49cc two-strokes
Ch-ch-changes: Vespa standard pistons changed in 1978 and 1980. Bikes made during those years can have either the older or the newer piston. There is no way to tell by ID numbers.
China
1978 bore reduction: In 1978 on US models the bore was reduced from 38.4 to 38.2mm. Some ’78’s have a 38.4 bore, and some have a 38.2 bore. Same thing happened to Minarelli at that same time (a reduction from 38.8 to 38.7). The pistons changed because of legal requirements.
1979-80 Dykes upper ring: In 1979 and 1980 the upper piston ring changed to L shape known as Dykes. Some ’79’s have regular top rings, and some have Dykes. Oversize Piaggio pistons already had Dykes upper rings since about 1977. This ring style was also adopted by Derbi in the mid-70’s and Puch in the late 70’s. It was mainstream in 1979! But by the mid-1980’s L-rings became out of style and obsolete. They did cost more to make, and broke easier. There was not much benefit. So all 90’s and later two-stroke moped engines have rectangular or trapezoidal top rings, mostly thinner than older designs.
SC means exhaust (scoria): All original pistons are made by Piaggio and say Piaggio or have the logo on the inner side. They all have an arrow on top with the letters “SC”. That means “scoria”, Italian for “exhaust”. During installation, the arrow points toward the exhaust. Vespa pistons have skirt cut-outs rotated 30 deg.
Ring gap: Piaggio specifies the ring gap to be 0.1 to 0.25 mm (0.004 to 0.010″)
10 or 12mm piston pins: Almost all of the Vespa mopeds in the USA had pistons with 12mm wrist pins, while Europe and other parts of the world have both 10 and 12mm piston pins. That is because the pin was 12mm from 1967 to 1984. And then 10mm from 1984 on. By 1984 there were not many USA moped sales. Then Vespa quit selling US mopeds in about 1985, but continued in Europe.
Piston versions: By having all of the Piaggio Parts Manuals, and especially the Parts Amendments 1, 2, 3 etc, it was possible to extract all of the Vespa (Piaggio) moped piston and ring part numbers. The millimeter sizes are not in any parts manual. They are from service manuals and actual parts new and used.
12-21 pistons for Minarelli V1L V1HL V1HLE, Suzuki FA50 FS50 FZ50
0000000000 part# lower x = 2, 3, or 4
pin up lo bore M# skirt ring1 ring2 maker price 40.3 bore, 12 pin, 21.5 upper
12-21-15-40.30-0 40.2x L2.0n c1.5n Mina. n.a. 4541 Minarelli V1L case reed, all-iron cyl
12-21-15-40.30-1 40.2x c1.5n c1.5n Mina. n.a. 4543 Minarelli V1HL same, sleeved al. cyl
pin up lo bore M# skirt ring1 ring2 maker price 40.6 bore, 12 pin, 21.5 upper
12-21-15-40.60-0 40.5x L2.0n c1.5n Mina. n.a. 4551 1os Minarelli V1L
12-21-15-40.60-1 40.5x c1.5n c1.5n Mina. n.a. 4553 1os Minarelli V1HL, V1HLE
pin up lo bore M# skirt ring1 ring2 maker price 40.8 bore, 12 pin, 21.5 upper
12-21-15-40.80-0 40.7x L2.0n c1.5n Mina. n.a. 4561 2os Minarelli V1L
12-21-15-40.80-1 40.7x c1.5n c1.5n Mina. n.a. 4563 2os Minarelli V1HL, V1HLE
Suzuki FA50
pin up lo bore M# skirt ring1 ring2 maker price 41.0 bore, 12 pin, 21 upper
12-21-15-41.00-0 40.92 t1.5n t1.5n Suzuki n.a. 12110.43000Suzuki FA50, FS50, FZ50
pin up lo bore M# skirt ring1 ring2 maker price 41.5 bore, 12 pin, 21 upper
12-21-15-41.50-0 41.4x t1.5n t1.5n Suzuki n.a. 12100.35611.050 1os Suzuki FA50, FS50, FZ50
pin up lo bore M# skirt ring1 ring2 maker price 42.0 bore, 12 pin, 21 upper
12-21-15-42.00-0 41.9x t1.5n t1.5n Suzuki n.a. 12100.35611.100 2os Suzuki FA50, FS50, FZ50
Sachs 504 1A
12-22 pistons for Minarelli V1, V1H, Sachs 504, 505, Morini S5
pin up lo bore M# skirt ring1 ring2 maker price 38.0 bore, 12 pin, 22 upper
12-22-14-38.00-0 37.95 c1.5n c2.0n Mahle n.a. 0286-378-051 Sachs 504,505 1C,1D 553
12-22-14-38.00-1 37.95 c1.5n c2.0n generic $55 406500 Sachs 504,505 1C,1D says 38
12-22-15-38.00-0 37.93 c2.5n c2.5n Asso $75 71.0455.0=4500 early Minarelli says Asso 825
12-22-15-38.00-0 37.93 c2.5n c2.5n Asso $00 ’56-70+ Min. P3, others ’69-79 Min. V1 1hp
12-22-15-38.00-0 37.93 c2.5n c2.5n Asso $00 ’51-55 FBM P48, P3, ’56-66 Morini F1, 3M
12-22-16-38.00-A 37.95 c2.0n c2.0n AMF $60 original AMF BHE900 rear eng, says 38
12-22-17-38.00-0 37.96 c2.0n c2.0n Mahle $75 0286-378-005 Sachs 504 1A,1B,
12-22-16-38.00-0 37.96 c2.0n c2.0n Mahle $00 Sachs 505 1A,1B 552 says 37.98 G8
12-22-17-38.00-1 37.93 c2.0n c2.0n Asso $59 23-0101 Morini S5K, S5K2 says Asso 771
12-22-17-38.00-2 37.96 c2.0n c2.0n Meteor $60 PC0922D Sachs 504,505 1A,1B Italian made
Morini S5K2
pin up lo bore M# skirt ring1 ring2 maker price 38.2 bore, 12 pin, 22 upper
12-22-16-38.20-0 38.1x c2.5n c2.5n Asso n.a. 71.0455.7=4510 1os Minarelli V1 1hp 20mph
12-22-17-38.20-1 38.1x c2.0n c2.0n Asso n.a. 23-0102 1os Morini S5K2, can use Min. 4510?
pin up lo bore M# skirt ring1 ring2 maker price 38.4 bore, 12 pin, 22 upper
12-22-16-38.40-0 38.3x c2.5n c2.5n Asso n.a. 71.0455.7=4520 2os Minarelli V1 1hp 20mph
pin up lo bore M# skirt ring1 ring2 maker price 38.6 bore, 12 pin, 22 upper
12-22-14-38.60-0 38.55 c1.5n c2.0n Mahle n.a. 0286-378-052 1os Sachs 504,505 1C,1D
12-22-16-38.60-0 38.5x c2.5n c2.5n Asso n.a. 71.0455.7=4530 3os Minarelli V1 1hp 20mph
Minarelli
12-22-17-38.60-1 38.55 c2.0n c2.0n Mahle $60 0286-378-006 1os Sachs 504,505 1A,1B
pin up lo bore M# skirt ring1 ring2 maker price 38.7 bore, 12 pin, 22 upper
12-22-16-38.70-0 38.62 c1.5n c1.5n Mina. n.a. 71.0406.0=4535 Minarelli V1 ’78-on-USA
pin up lo bore M# skirt ring1 ring2 maker price 38.8 bore, 12 pin, 22 upper
12-22-16-38.80-0 38.72 c1.5n c1.5n Mina. $75 71.0410.0=4540 Min.V1 pre-’79-US
12-22-16-38.80-0 38.72 c1.5n c1.5n Minn. $00 Minarelli P4 iron cyl
12-22-16-38.80-1 38.72 c1.5n c1.5n GOL $60 0034 Minarelli V1 exact replacement
12-22-16-38.80-2 38.73 L2.0n c2.0n Asso $60 4540HP Demm Smily piston, fits Minarelli
Mor. S5R S5E
pin up lo bore M# skirt ring1 ring2 maker price 39.0 bore, 12 pin, 22 upper
12-22-16-39.00-0 38.92 c1.5n c1.5n Mina. $73 71.0460.7=4550 1os Minarelli V1
12-22-15-38.96-0 38.94 L2.0n c2.0i Asso $70 23-0133A Morini S5R, S5E Asso 1386
12-22-15-38.99-0 38.95 L2.0n c2.0i Asso n.a. 23-0133B Morini S5R, S5E Asso 1386
12-22-15-38.99-0 38.96 L2.0n c2.0i Asso n.a. 23-0133C Morini S5R, S5E Asso 1386
12-22-15-38.99-0 38.97 L2.0n c2.0i Asso n.a. 23-0133D Morini S5R, S5E Asso 1386
12-22-15-38.99-0 38.98 L2.0n c2.0i Asso n.a. 23-0133E Morini S5R, S5E Asso 1386
pin up lo bore M# skirt ring1 ring2 maker price 39.2 bore, 12 pin, 22 upper
12-22-16-39.20-0 39.12 c1.5n c1.5n Mina. n.a. 71.0460.7=4560 2os Minarelli V1
pin up lo bore M# skirt ring1 ring2 maker price 39.4 bore, 12 pin, 22 upper
12-22-16-39.40-0 39.32 c1.5n c1.5n Mina. $75 71.0460.7=4570 3os Minarelli V1
12-22-16-39.40-0 39.3x c1.5n c1.5n Minn. n.a. original Harley Davidson M50 std
Connection:
1950’s to 1970’s
pin up lo bore M# skirt ring1 ring2 maker price 39.6 bore, 12 pin, 22 upper
12-22-16-39.60-0 39.52 c1.5n c1.5n Mina. n.a. 71.0460.7=4580 4os Minarelli V1
pin up lo bore M# skirt ring1 ring2 maker price 39.8 bore, 12 pin, 22 upper
12-22-16-39.80-0 39.7x c1.5n c1.5n Mina. n.a. 71.0460.7=4590 5os Minarelli V1
pin up lo bore M# skirt ring1 ring2 maker price 40.0 bore, 12 pin, 22 upper
12-22-16-40.00-0 39.9x c1.5n c1.5n Asso? n.a. 208703.2.150 Garelli Monza GT,
12-22-16-40.00-0 39.9x c1.5n c1.5n Asso? none has port window(s), flat top
pin up lo bore M# skirt ring1 ring2 maker price 45.4 bore, 12 pin, 22 upper
12-22-18-45.40-0 45.33 c1.5n c1.5n Mina. $70 71.0485.7 Minarelli 70cc new in box
pin up lo bore M# skirt ring1 ring2 maker price 46.0 bore, 12 pin, 21.5 upper
12-22-15-46.00-0 45.93 L2.0n c1.5i Asso $70 23-0140 Morini 70cc, says Asso W 2508
pin up lo bore M# skirt ring1 ring2 maker price 47.1 bore, 12 pin, 22.5 upper
12-22-15-47.10-0 47.03 L2.0n c1.5i Asso $70 23-01?? Morini 70cc AW 2666, AA on top
Ø40 top
says 401
12-23 pistons for Casal M140 engine on K177, Zundapp?
pin up lo bore M# skirt ring1 ring2 maker price 40.0 bore, 12 pin, 23 upper
12-23-16-39.98-D 39.96 c2.0n c2.0n Mahle $70 Casal alum cyl 39.98 D Mahle 401
12-23-16-39.99-E 39.97 c2.0n c2.0n Mahle n.a. Casal alum cyl 39.99 E Mahle 401
12-23-16-40.00-F 39.98 c2.0n c2.0n Mahle n.a. Casal alum cyl 40.00 F Mahle 401
Ø48 top
says 481
pin up lo bore M# skirt ring1 ring2 maker price 48.0 bore, 12 pin, 23 upper
12-23-16-47.98-D 47.96 c2.0n c2.0n Mahle n.a. Casal alum cyl 47.98 D Mahle 481
12-23-16-47.99-E 47.97 c2.0n c2.0n Mahle n.a. Casal alum cyl 47.99 E Mahle 481
12-23-16-48.00-F 47.98 c2.0n c2.0n Mahle n.a. Casal alum cyl 48.00 F Mahle 481
Casal (made in Portugal) pistons are made in Germany by Mahle. They say “saida” on top, exhaust side, Portuguese for “outlet”.
Casal pistons have an unusual flat bottom. They have a total height of 50mm. Top edge to pin is 23mm, plus pin 12mm, plus pin to bottom edge 15mm. There are two bore choices 40 and 48mm, each with several 0.01mm (micro!) increments to get a precise fit. A cylinder of letter “F” should get a matching “F” piston, unless it is worn, then maybe a “G” or even an “H” would be best. If the piston fit is too loose the engine will be weak, noisy, and fussy. Too tight and it will seize and do damage. Piston rings are both size 40 x c2.0n (FG gap style), like Garelli.
Indian 4-stroke
13-14 pistons forIndian 78-81 AMI-50, Honda 75-77 PC50K1
pin up lo bore M# skirt xxxxooo price 42.0 bore, 13 pin, 13.5 upper
13-14-14-42.00-0 41.96 bare xxx $43 E650-00-50 Indian AMI50, Honda PC50K1
13-14-14-42.00-1 41.96 complete $78 6131 standard size
pin up lo bore M# skirt xxxxooo price 42.25 bore, 13 pin, 13.5 upper
13-14-14-42.25-0 42.21 bare xxx $45 E650-10-50 1os In. AMI50, Hon PC50K1
13-14-14-42.25-1 42.21 complete $78 6132 1os first over size
13-15 pistons for Motobecane 1977-80 40, 50, 50V Mobylette
pin up lo bore M# skirt ring1 ring2 maker price 39.0 bore, 13 pin, 15.5 upper
13-15-22-38.95-0 38.94 c2.0i c2.0i MBK n.a. 22273 Motobecane alu cyl 38.95 sort 2
13-15-22-38.96-0 38.95 c2.0i c2.0i MBK $70 22274 Motobecane alu cyl 38.96 sort AA
13-15-22-38.97-0 38.96 c2.0i c2.0i MBK $70 22275 Motobecane alu cyl 38.97 sort A
13-15-22-38.97-1 38.96 c2.0i c2.0i SC Θ $68 same
13-15-22-38.98-0 38.97 c2.0i c2.0i MBK n.a. 22276 Motobecane alu cyl 38.98 sort C
13-15-22-38.99-0 38.98 c2.0i c2.0i MBK $70 22277 Motobecane alu cyl 38.99 sort E
13-15-22-39.00-0 38.99 c2.0i c2.0i MBK $70 22278 Motobecane alu cyl 39.00 sort G
13-15-22-39.01-0 39.00 c2.0i c2.0i MBK n.a. 22279 Motobecane alu cyl 39.01 sort J
13-15-22-39.01-1 39.00 c2.0i c2.0i SC Θ $68 same
13-15-22-39.02-0 39.01 c2.0i c2.0i MBK n.a. 22280 Motobecane alu cyl 39.02 sort L
13-15-22-39.03-0 39.02 c2.0i c2.0i MBK $70 22281 Motobecane alu cyl 39.03 sort N
13-15-22-39.04-0 39.03 c2.0i c2.0i MBK $70 22435 Motobecane alu cyl 39.04 sort P says P
pin up lo bore M# skirt ring1 ring2 maker price 39.12 bore, 13 pin, 15.5 upper
13-15-22-39.12-0 39.11 c2.0i c2.0i O BK $68 22435a Motobecane cyl 39.12 oversize
14-18 pistons for Jawa Babetta 207 1970-83
Jawa original pistons were sold with rings, but without pin or clips.
pin up lo bore M# skirt ring1 ring2 maker price 39.0 bore, 14 pin, 18 upper
14-18-15-39.00-0 38.94 L2.0n none Meteor n.a. 281218a xxxx Jawa 210?
Jawa 207
pin up lo bore M# skirt ring1 ring2 maker price 39.03 bore, 14 pin, 18 upper
14-18-15-39.02-0 38.97 c2.0i c2.0i Jawa n.a. 281218A xxxx Jawa 207, says A Y
14-18-15-39.03-0 38.98 c2.0i c2.0i Jawa n.a. 281218B xxxx Jawa 207, says B Y
14-18-15-39.04-0 38.99 c2.0i c2.0i Jawa n.a. 281218C xxxx Jawa 207, says C Y
pin up lo bore M# skirt ring1 ring2 maker price 39.28 bore, 14 pin, 18 upper
14-18-15-39.27-0 39.22 c2.0i c2.0i Jawa n.a. 281218/1A 1os Jawa 207, says 1A Y
14-18-15-39.28-0 39.23 c2.0i c2.0i Jawa $60 281218/1B 1os Jawa 207, says 1B Y
14-18-15-39.29-0 39.24 c2.0i c2.0i Jawa n.a. 281218/1C 1os Jawa 207, says 1C Y
pin up lo bore M# skirt ring1 ring2 maker price 39.53 bore, 14 pin, 18 upper
14-18-15-39.52-0 39.47 c2.0i c2.0i Jawa n.a. 281218/2A 2os Jawa 207, says 2A Y
14-18-15-39.53-0 39.48 c2.0i c2.0i Jawa n.a. 281218/2B 2os Jawa 207, says 2B Y
14-18-15-39.54-0 39.49 c2.0i c2.0i Jawa n.a. 281218/2C 2os Jawa 207, says 2C Y
pin up lo bore M# skirt ring1 ring2 maker price 39.78 bore, 14 pin, 18 upper
14-18-15-39.77-0 39.72 c2.0i c2.0i Jawa n.a. 281218/3A 3os Jawa 207, says 3A Y
14-18-15-39.78-0 39.73 c2.0i c2.0i Jawa n.a. 281218/3B 3os Jawa 207, says 3B Y
14-18-15-39.79-0 39.74 c2.0i c2.0i Jawa n.a. 281218/3C 3os Jawa 207, says 3C Y
pin up lo bore M# skirt ring1 ring2 maker price 40.03 bore, 14 pin, 18 upper
14-18-15-40.02-0 39.97 c2.0i c2.0i Jawa n.a. 281218/4A 4os Jawa 207, says 4A X
14-18-15-40.03-0 39.98 c2.0i c2.0i Jawa $65 281218/4B 4os Jawa 207, says 4B X
14-18-15-40.04-0 39.99 c2.0i c2.0i Jawa n.a. 281218/4C 4os Jawa 207, says 4C X
Size translation: The table says a “1B” piston is 39.21 mm, measured “34,5mm from the base” just below the lower ring. Four “1B” pistons actually measured 39.21 there, and 39.23 at the skirt. Other “1B” pistons were 39.20 and 39.22, 39.21 and 39.22, and 0.02 more at the skirt. Other samples were “B” (standard) 38.94 and 38.96, “2B” 39.44 and 39.46, “3B” 39.70 and 39.73, “4B” two at 39.95 and 39.97, all 0.02 wider at the skirt. Based on these eleven new pistons, all measured the same way at the same time, the Jawa piston sizes can be translated to standard piston sizes. Jawa piston sizes (measured at the lower ring) are, on average, 0.02 mm less than standard piston sizes (measured at the skirt).
Piston to cylinder clearance: From the Puch service manual the piston to cylinder clearance for a similar steel sleeved aluminum cylinder, is min 0.030, max 0.055 mm. From the Jawa table of piston sizes (at right), it says the new piston-to-cylinder clearance is min 0.065, max 0.075 mm. Subtracting 0.02 mm from this gives min 0.045, max 0.055, more in agreement with Puch.
Flandria
14-24 pistons for Flandria Bermuda
pin up lo bore M# skirt ring1 ring2 maker price 40.0 bore, 14 pin, 24 upper
14-24-12-40.00-0 39.9x c1.5n c1.5n Fland. n.a. Flandria Bermuda 1977
This is unusual in many ways. The transfer flows through the piston instead of around it.
The wrist pin is lowered to allow more intake air flow. This upper length of 24 is the most for 50cc pistons. The wrist pin measures 13.98 x 33 mm.
100’s more vintage replacement pistons of all sizes are in the GOL Pistons Vintage Catalog, a pdf download.