updated 2019-12
Contents:
1. Piston Rings 2. Ring Info
3. Pistons Ring 4. Piston Info
1. Piston Rings
Listed as: D x h x w xxx Listed as: D x h1/h2 x w xxx Listed as: D x h1/h2 x w1/w2 xxx Listed as: N or I xxxxxxxxxxx
GN gap (aka FG)
pin on side of groove
Meanings:
D is the cylinder diameter that the ring would have a 0.004 to 0.008″ gap in
height is the thickness up-and-down. T & L rings have 2 heights, outer & inner
width is the depth inward-and-out. L rings have two widths, outer and inner
type C = Common “square” shape (cross-section)
type T = Trapezoidal “slant top” shape (cross-section)
type L = L-shape aka “Dykes” shape (cross-section)
GI gap style
pin inside groove
gap GN Grano Normale gap style is for ring pin on side of ring groove
gap GI Grano Interno = gap style is for ring pin in center of ring groove
gap (blank) is for L-ring gap style, ring is like a GI but groove is like a GN
price is for each ring, unless noted. All rings are for 50cc engines, unless noted.
R I N G S
0 size x height x width type gap price part number applications
36.50 x 1.50 1./x 1.7/0.7 C N $10.0 0 0000 222812 Tomos MC36 36cc
38.00 x 1.50 1./x 1.7/0.7 C I $10.0 0 0215.100.100 Sachs 1979-on 504,505 1C,1D upper
38.00 x 1.50 1./x 1.7/0.7 C N cont.. 00.. 000000000 Zanetti (front engine)
38.00 x 1.5/1.3 x 1.60 /7 T N $17.0 0..0000 223707 Tomos A55 (2001-06) superseded in ’07 to 236802
38.00 x 1.50 1./x 1.7/0.7 C N $$9.0 0..0000 236802 Tomos A35 (1991-06), Tomos A55 (2007-on)
38.00 x 1.50 1./x 1.7/0.7 C N cont.. 0 000.672.5110 Derbi 1976-1986 lower only, Odyssey, Solo
38.00 x 2.0/1.0 x 1.5/0.5 L N $10.0 0 000.802.5110 Derbi 1976-1986 upper (fits Puch loose inner)
38.00 x 2.0/1.0 x 1.7/0.7 L N $21.0 0 328.110.9601 Puch 1979-1980 deluxe models upper
38.00 x 2.00 1./x 1.7/0.7 C N $13.0 0 331.110.1601 Puch rounded edge for aluminum cylinder
38.00 x 2.00 1./x 1.7/0.7 C N $$9.0 0 320.110.0601 Puch except some ’79-80 upper
38.00 x 2.00 1./x 1.7/0.7 C N cont.. 0 0215.009.000 Sachs 504, 505 1A,1B both, 1C,1D lower
38.00 x 2.00 1./x 1.7/0.7 C N cont.. 0..0000 044754 Tomos A3 1975-1990, AMF BHE900 rear engine
38.00 x 2.00 1./x 1.7/0.7 C N cont.. 00.000 26.1001 Morini S5K, S5K2, 2M, 3M, F48
38.00 x 2.50 x 1.50.7/0.7 C N $11.0 71.0802.0 4600 Minarelli V1 1hp 20mph, Sears Allstate, early Puch
38.00 x 2.50 1./x 1.7/0.7 C flat N/A 0.00000000000 Solex 45cc 1946-1954 use 38.00 x 2.50 C N
38.20 x 1.50 1./x 1.7/0.7 C N $10.0 0..0000 182518 Piaggio 79-later & some 78s lower ring
38.20 x 2.00 1./x 1.7/0.7 C N $16.0 00..000 166945 Piaggio 78-80 USA-type, must file down a 077775
38.00 x 2.00 1./x 1.7/0.7 C N cont.. 0000.0 26.1002 1os Morini S5K, S5K2, 2M, 3M, F48
38.20 x 2.0/1.0 x 1.8/.75 L N $14.0 0..0 000182519 Piaggio 79-later & some 78s upper ring
38.20 x 2.50 x 1.50.7/0.7 C N none.. 71.0852.7 4610 Minarelli 1os V1 1hp 20mph, Sears Allstate, early Puch
38.25 x 2.0/1.0 x 1.5/0.5 L N $11.0 0 000.802.5110 1os Derbi 1976-1986 upper ring
38.25 x 1.50 1./x 1.7/0.7 C N $15.0 0 000.672.2511 1os Derbi lower
38.40 x 1.50 1./x 1.7/0.7 C N $14.0 00 000 132515 std or 1os Piaggio lower ring, 79-later & some 78s
38.40 x 1.5/1.3 x 1.60 /7 T N N/A 0 000 3010010 Kinetic TFR (Vespa Si remake) 95-later
38.40 x 2.00 1./x 1.7/0.7 C N $12.0 0 0000 077775 Piaggio 77-earlier & some 78s, early Kinetic
38.40 x 2.0/1.0 x 1.8/.75 L N none.. 0 000 G.68473 std or 1os Piaggio upper ring, 79-later & some 78s
38.40 x 2.50 x 1.50.7/0.7 C N $9.00 71.0852.7 4620 Minarelli 2os V1 1hp 20mph, Sears Allstate, early Puch
38.50 x 1.50 1./x 1.7/0.7 C N $12.0 0 0000 227758 1os Tomos A35
38.50 x 2.00 1./x 1.7/0.7 C N $10.0 0 0000 044751 1os Tomos A3
38.60 x 1.50 1./x 1.7/0.7 C N $9.00 000000 137693 1os or 2os Piaggio
38.60 x 2.00 1./x 1.7/0.7 C N $14.0 0 00000 98196 1os Sachs 504, 505, 2os Piaggio 79- lower
38.60 x 2.0/1.0 x 1.8/.75 L N $13.0 0 00000 137690 1os or 2os Piaggio upper ring, 79-later & some 78s
38.70 x 1.50 1./x 1.7/0.7 C N $16.0 71.0803.0 4635 Minarelli V1 (US 1979-on and some ’78)
38.80 x 2.0/1.0 x 1.65/.6 L N $11.0 0 4.7470.5140 Demm Smily upper
38.80 x 1.50 x 1.50.7/0.7 C N cont.. 0000 68.0116.0 Minarelli P4 (export al-cyl, Compact System, Radiale) upper
38.80 x 2.0/1.0 x 1.8/.75 L N $11.0 000000 137691 2os Piaggio upper ring
38.80 x 1.50 x 1.50.7/0.7 C N $10.0 71.0805.0 4640 Minarelli V1 (US to-1978)
38.80 x 1.50 x 1.50.7/0.7 C N cont.. 0000 68.0115.0 Minarelli P4 (export iron-cyl, Sport Quadro) both
38.80 x 1.50 x 1.50.7/0.7 C N cont.. 0000 68.0115.0 Minarelli P4 (export al-cyl, Compact System, Radiale) lower
38.80 x 1.50 x 1.50.7/0.7 C N cont.. 00.00 137694 2os Piaggio upper ring
38.80 x 1.50 1./x 1.7/0.7 C I N/A 00000 22350-65 Aermacchi Harley Davidson M50 1965-66 stroke 42
38.80 x 2.00 1./x 1.7/0.7 C N $10.0 00 4.7470.5100 Demm Smily lower
39.00 x 1.00 1./x 1.7/0.7 C N $19.0 0.000 26.1060 Morini S5N, S5GS kids off road, both
39.00 x 1.2/1.0 x 1.70 /7 T I N/A 13011.GE2.305a Honda NS50 upper
39.00 x 1.20 x 1.85 /0..7 C I $10.013011.GE2.305b Honda NS50 lower
39.00 x 1.50 1./x 1.7/0.7 C N $10.0 71.0855.7 4650 1os Minarelli V1, P4, P4 (alum cyl) lower
39.00 x 1.50 1./x 1.7/0.7 C N cont.. 00.00 26.1044 Morini S5R, S5T, S5E, S5ET kids off road, lower
39.00 x 1.50 1./x 1.7/0.7 C I $10.0 0000 22351-65 1os Aermacchi Harley Davidson M50 1965-66
39.00 x 2.00 1./x 1.7/0.7 C I $12.0 000000 22148 Motobecane (GI after June 1976)
39.00 x 2.00 1./x 1.7/0.7 C N $10.0 000000 22148 Motobecane (FG before July 1975), DiBlasi mini-cycle
39.00 x 2.0/1.0 x 1.8/0.7 L N $11.0 00000 26.1003 Morini S5R, S5T alum. cylinder (upper ring)
39.03 x 2.00 1./x 1.7/0.7 C I $14.0 00 00 2812200 Jawa 207 1970-83 standard
39.20 x 1.50 1./x 1.7/0.7 C N $15.0 71.0855.7 4660 2os Minarelli V1, P4, P4 (al-cyl) lower
39.20 x 1.50 1./x 1.7/0.7 C I N/A 00000 22352-65 2os Aermacchi Harley Davidson M50 1965-66
39.25 x 1.2/1.0 x 1.70 /7 T I $19.013012.GE2.305a 1os Honda NS50 upper
39.25 x 1.20 x 1.85 /0..7 C I $10.013012.GE2.305b 1os Honda NS50 lower
39.28 x 2.00 x 1.65 /0..7 C I $14.0 00 00 2812201 1os Jawa 207 1970-83
39.40 x 1.50 1./x 1.7/0.7 C N N/A 71.0855.7 4670 3os Minarelli V1, P4, P4 (al-cyl) lower
39.40 x 1.50 1./x 1.7/0.7 C I N/A 00000 22353-65 3os Aermacchi Harley Davidson M50 1965-66
39.40 x 2.50 1./x 1.7/0.7 C N N/A 000 0 0000000 Rizzato Califfo 1978 (Rizzato 119 engine)
39.50 x 1.2/1.0 x 1.70 /7 T I N/A 13013.GE2.305a 2os Honda NS50 upper
39.50 x 1.20 x 1.85 /0..7 C I $10.013013.GE2.305b 2os Honda NS50 lower
39.50 x 1.70 x 1.60 /0..7 C flat $10.0 00 0000 60817 Solex rings (3) no locating pins
39.53 x 2.00 x 1.65 /0..7 C I $19.0 00 00 2812202 2os Jawa 207 1970-83
39.60 x 1.50 1./x 1.7/0.7 C N $17.0 71.0855.7 4680 4os Minarelli V1, P4, P4 (al-cyl) lower
39.80 x 1.50 1./x 1.7/0.7 C N $17.0 71.0855.7 4690 5os Minarelli V1, P4, P4 (al-cyl) lower
39.80 x 2.50 1./x 1.7/0.7 C N $10 000 0 0000000 1os Rizzato Califfo 1978 (Rizzato 119 engine)
40.00 x 1.2/1.0 x 1.60 /7 T N $14.0 000 00 633086 China 49cc two-strokes upper, most
40.00 x 1.2/1.0 x 1.70 /7 T I $14 2W1.11610.0000a Yamaha YSR50 upper, PGO Star 50 upper, others
40.00 x 1.20 x 1.85 /0..7 C I $13 2W1.11610.0000b Yamaha YSR50 lower, PGO Star 50 lower, others
40.00 x 1.5/1.3 x 1.80 /7 T N $14.0 13011.147.005a Dailim Trac, upper for Honda NC50,PA50,Yamaha QT50
40.00 x 1.50 1./x 1.7/0.7 C N $10.0 00 0000 55196 Batavus M48, M56, Trac (not Daelim), Flandria Bermuda
40.00 x 1.50 1./x 1.7/0.7 C N cont.. 13011.147.005b Honda lower for NC50,PA50, Yamaha QT50 lower
40.00 x 1.50 1./x 1.7/0.7 C N cont.. 000000 G7347 Benelli G2, 1965-75 Ward Riverside, Benelli mini-cycles
40.00 x 1.50 1./x 1.7/0.7 C N cont.. 00000 26.1044 Morini S5R, S5T alum. cylinder (lower ring)
40.00 x 1.50 1./x 1.7/0.7 C I $10.0 00000 551913 Morini MO Gyromat,Convert (early ’70s MO1,MO2)
40.00 x 1.50 1./x 1.7/0.7 C I cont.. 0F0.250.0111 Derbi 1986-1989 flat reed, Kreidler Flory
40.00 x 2.00 1./x 1.7/0.7 C N $10.0 00 307.021.00 Garelli all 1970’s, 00’s Avanti/Mont (most)
40.00 x 2.00 1./x 1.7/0.7 C N cont.. 00 307.021.00 Casal K177, 2000’s Hero Majestic Pacer
40.00 x 2.0/1.0 x 1.8/0.7 L N $11.0 00 310.001.00 Garelli Monza GT upper
40.00 x 2.50 1./x 1.7/0.7 C I $15.0 0000000 38315 Peugeot 102, 103 (almost all US models)
40.20 x 1.50 1./x 1.7/0.7 C N $22.0 0000 G7347/2 1os Benelli, 1os M Ward, filed down 40.25
40.20 x 2.00 1./x 1.7/0.7 C N $15.0 00 308.027.00 1os Garelli
40.25 x 1.00 1./x 1.7/0.7 C N $12.0 000..00 633087 1os China 49cc two-stroke scooter
40.25 x 1.5/1.3 x 1.80 /7 T N N/A 13021.147.005a 1os Honda NC50, PA50 upper
40.25 x 1.50 1./x 1.7/0.7 C N $15.013021.147.005b 1os Honda NC50, PA50 lower, 480511 1os Laura M48
40.30 x 1.50 1./x 1.7/0.7 C N $19.0 000000 4641b Minarelli V1HL and V1L lower, filed down 40.5
40.30 x 2.0/1.0 x 1.8/0.7 L N N/A 000000 4641a Minarelli V1L upper
40.40 x 1.50 1./x 1.7/0.7 C N N/A 0000 G7347/4 2os Benelli G2, 2os M Ward and mini-cycles
40.40 x 1.50 1./x 1.7/0.7 C I $$9.0 00 00 26.1045 Morini MO1, MO2, MO4, M1
40.40 x 2.00 1./x 1.7/0.7 C N $12.0 0 0 308.028.00 2os Garelli
40.50 x 1.5/1.3 x 1.80 /7 T N N/A 13031.147.005a 2os Honda NC50, PA50 upper
40.50 x 1.50 1./x 1.7/0.7 C N $12.013031.147.005b 2os Honda NC50, PA50 lower, 2os Laura M48
40.50 x 2.50 1./x 1.7/0.7 C I $12.0 00 0000 33648 1os Peugeot 102, 103 (some, but none in CA)
40.60 x 1.50 1./x 1.7/0.7 C N $16.0 00000 G7347/6 3os Benelli, 3os M Ward
40.60 x 1.50 1./x 1.7/0.7 C N cont.. 71.0860.7 4651b 1os Minarelli V1L lower
40.60 x 1.50 1./x 1.7/0.7 C I $12.0 0000 26.1046/6 1os Morini MO1, MO2, MO4, M1
40.60 x 2.00 1./x 1.7/0.7 C N $10.0 0 0 308.029.00 3os Garelli
40.60 x 2.0/1.0 x 1.65/.6 L N $15.071.0860.7 4651a 1os Minarelli V1L upper
40.75 x 1.5/1.3 x 1.80 /7 T N N/A 13041.147.005a 3os Honda NC50, PA50 upper
40.75 x 1.50 1./x 1.7/0.7 C N N/A 13041.147.005b 3os Honda NC50, PA50 lower
40.80 x 1.50 1./x 1.7/0.7 C I $12.0 000 26.1046/8 2os Morini MO1, MO2, MO4, M1
40.80 x 1.50 1./x 1.7/0.7 C N $9.0 71.0860.7 4661b 2os Minarelli V1L lower
40.80 x 2.0/1.0 x 1.65/.6 L N N/A 71.0860.7 4661a 2os Minarelli V1L upper
40.80 x 2.00 1./x 1.7/0.7 C N $10.0 00 308.030.00 4os Garelli
41.00 x 1.2/1.0 x 1.90 /7 T I $14 13010.GJ5.015a Honda TG50, NN50 Gyro upper
41.00 x 1.2/1.0 x 1.90 /7 C I N/A 13010.GJ5.015b Honda TG50, NN50 Gyro lower
41.00 x 1.5/1.3 x 1.80 /7 T I $14.0 0 12140-16B10 Suzuki FY50, FZ50, FA50 upper
41.00 x 1.50 1./x 1.7/0.7 C N $10.0 0000000 00000 Minarelli V1 Industriale 53cc stroke 42
41.40 x 1.50 1./x 1.7/0.7 C I $12.0 0000000 00000 Unknown only one
42.00 x 1.50 1./x 1.7/0.7 C N N/A 0 00000 00000 Minarelli V1 Carabela 58cc stroke 42
42.00 x 2.00 1./x 1.7/0.7 C N $12.0 0000000 00000 Unknown only two
42.00 x 1.50 1./x 1.7/0.7 C flat $40/set E660-00-50 Indian 4-stroke ring set comp(2) oil(1)
42.25 x 1.50 1./x 1.7/0.7 C flat $40/set E660-10-50 1os Indian 4-stroke set comp(2) oil(1)
42.50 x 1.50 1./x 1.7/0.7 C flat N/A E660-20-50 2os Indian 4-stroke set comp(2) oil(1)
42.75 x 1.50 1./x 1.7/0.7 C N $12.0 0000000 00000 big bore kit appr 60cc only two
43.00 x 1.50 1./x 1.7/0.7 C N $12.0 0000000 00000 big bore kit appr 60cc only one
43.00 x 2.0/1.0 x 1.65/.6 L N $16.0 0000000 00000 big bore kit appr 60cc only one
43.50 x 1.50 1./x 1.7/0.7 C N $10.0 0000000 00000 big bore kit appr 60cc
44.00 x 1.50 1./x 1.7/0.7 C N $10.0 0000000 G-591 Benelli Dynamo 65 59cc stroke 39
44.00 x 1.50 1./x 1.7/0.7 C N cont.. 00000 MF-554 big bore kit Peugeot 103 59cc
44.00 x 1.50 1./x 1.7/0.7 C I N/A 00000 22350-67 Aermacchi Harley Davidson M65 1967-72 64cc stroke 42
44.20 x 1.50 1./x 1.7/0.7 C I N/A 00000 22351-67 1os Aermacchi Harley Davidson M65 1967-72 64.5
44.40 x 1.50 1./x 1.7/0.7 C I N/A 00000 22352-67 2os Aermacchi Harley Davidson M65 1967-72 65cc
45.00 x 1.50 1./x 1.7/0.7 C N N/A 0 0000. 71.8187 Minarelli P4-70, P6-70 67cc
45.20 x 1.50 1./x 1.7/0.7 C N N/A 0 0000. 71.8187 1os Minarelli P4-70, P6-70 67cc
45.40 x 1.50 1./x 1.7/0.7 C N N/A 0 0000. 71.8187 2os Minarelli P4-70, P6-70 67cc
2. Ring Information
Pinned or Not Pinned: Most moped piston rings are two-stroke style, where there are pins in the ring grooves of the piston that keep the rings from rotating around. Two stroke cylinders have holes or ports that the ring ends can snag on. So two stroke rings are pinned to the piston. Four stroke cylinders do not have any holes, so four stroke rings are not pinned. Knowing about those pins is important when installing.
Getting the right rings: If your model is not in the applications, then you must measure the bore and the ring thickness. A calipers is the best tool to measure the bore (ring diameter) and ring thickness. Sometimes your rings might not be original, for many reasons. The piston might be aftermarket with thinner rings. The cylinder might be bored out to an oversize bore. Some mopeds came with more than one piston size or ring style.
Break a ring, how not to: Two stroke pistons have little pins (stumps, bumps) in the piston ring grooves that prevent the rings from rotating. Knowing where each ring locating pin is, and aligning the ring gap over the pin during cylinder installation, is the key to not breaking the ring.
Measuring wear: A new piston ring is a the best tool to measure how worn a cylinder is. Conversely, a new cylinder is the best tool to measure how worn a ring is. To measure the wear of a ring, you need a perfectly round cylinder of a precisely known bore. A worn cylinder that has not been honed will still have it’s original new bore at the very top, above where the rings rub at. A new ring in a new cylinder should have a very small end gap of .004 to .008″. A worn but still OK cylinder with a new ring will have a gap of .0010 to .018″. A worn cylinder and ring both will have an end gap of over .020″(.5mm). A badly worn cylinder and/or ring will have a huge gap, over .030″(.75mm). You measure ring gap with a feeler gauge.
Classifying Piston Rings
Classifying rings: Rings get mixed up and are difficult to tell the size, unless a perfectly round cylinder of an appropriate size is available to place the ring in. If you try to squeeze a piston ring into a circle with just fingers, it inevitably becomes a very rounded polygon, or at best an ellipse. So the measurement becomes inaccurate. At right is how Myrons Mopeds’s Jawa piston rings were classified, using a piece of aluminum tubing with a tight fitting piston inside it to hold the tube round, and the test ring square. From top to bottom, 39.03 x 2.0, 39.28 x 2.0, 39.53 x 2.0, 39.78 x 2.0mm. Each ring increases in diameter by 0.25mm, so the circumference increases by Pi times that, or about 0.8mm. Here the inside of an old fishing pole tube is 39.78mm, perfect for the 3rd oversize 39.78 ring, on the bottom, with a gap of almost zero. Each gap is 0.8mm more because each ring is 0.25mm less diameter. It is important that the piston and ring fit the cylinder properly.
Filing down: To make a ring slightly smaller, one of the two ring ends can be filed down, while preserving the shape. To reduce the size (diameter) by 0.20 mm, the end must be filed down by pi times that, 0.63 mm. When a filed down ring is installed in a cylinder smaller than it was designed for, two things change. The tension is greater, and the shape is slightly non-circular. So filed rings need a longer break-in period, to wear down the higher places. With 38 to 41 mm rings, the size can be reduced by 0.2mm with about 30 minutes of break-in, and by 0.5mm with about 2 hours of break-in. After break-in the rings have a mirror polish all around.
Why is the width not specified? Because the inner side of the ring does not touch anything. The ring has spring tension pushing it outwards, keeping the bottom (inner) surface from touching the bottom of the ring groove. So the ring width can be any amount, from about half the groove depth, to the groove depth. The exact ring width is not important. Exact ring height and diameter are important.
3. Pistons
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.
Alphabetical Name Index of Section Numbers
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 engine
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
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
10-18 1974-91 Tomos A3, 50’s-60’s Puch and Tomos
000000 part# lower @skirt ring1 ring2 maker price 38.0 bore, 10 pin, 18 upper
0000002074?? 24.0 37.94 c2.0n c2.0n Mahle none original Tomos A3 1.0hp (55 total height, 52 at edge)
000000207407 21.0 37.94 c2.0n c2.0n Mahle none original Tomos A3 1.5hp (52 total height, 49 at edge)
000000207403 19.0 37.94 c2.0n c2.0n Mahle $50 original Tomos A3 2.0hp (50 total height, 47 at edge)
000000207403a 19.0 37.95 c1.5n c1.5n generic $60 re-make Tomos A3
000000206200 18.0 37.9x c2.0n c2.0n generic none re-make Tomos A3
000501.1006.2 ???? 37.9x c2.5n c2.5n Mahle none original Sears Allstate
000000 part# lower @skirt ring1 ring2 maker price 38.5 bore, 10 pin, 18 upper
000000202420 19.0 38.45 c2.0n c2.0n Mahle none original Tomos A3 oversize
Tomos A3
50’s-60’s Puch
Tomos and Solo
Angel and Batavus
10-19 1976-80 Solo on Odyssey,Columbia, ’77-84 TYM Angel
000000 part# lower @skirt ring1 ring2 maker price 38.0 bore, 10 pin, 19 upper
0000002200593 22.0 37.9x c1.5n c1.5n Mahle none original Solo piston “N”
0000002200600 22.0 37.9x c1.5n c1.5n Mahle none original Solo piston “U”
000000 part# lower @skirt ring1 ring2 maker price 40.0 bore, 10 pin, 19 upper
0000000000000 15.0 39.92 c1.5n c1.5n generic none original Angel/Speed Bird
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.
10-20 1977-83 Honda NC50 PA50, Yamaha QT50 PW50
000000 part# lower @skirt ring1 ring2 maker price 40.0 bore, 10 pin, 20.5 upper
13101.147.000 18.0 39.95 t1.5n c1.5n Honda none original Honda NC50 and PA50 (has decomp cut)
13101.147.000a 18.0 39.95 t1.5n c1.5n generic $43.0 re-make Honda NC50, PA50
3L5.11630.00.00 17.5 39.9x t1.5n c1.5n Yamaha none original Yamaha QT50 Yamahopper and PW50
Honda NC50, PA50
Honda NC50
Yamaha QT50, PW50
Vespa Euro
Eton scooter
10-21 1990’s Vespa (Euro), China scooters
000000 part# lower @skirt ring1 ring2 maker price 38.2 bore, 10 pin, 21 upper
000000000000 17.0 38.13 L2.0n c1.5n Meteor $60 original Vespa 84-85 Ciao & Si, Euro models
000000 part# lower @skirt ring1 ring2 maker price 40.0 bore, 10 pin, 21 upper
000000632964 18.0 39.9x t1.2n t1.2n generic $60 re-make E-Ton 50cc 2-stroke scooter
000000 part# lower @skirt ring1 ring2 maker price 40.25 bore, 10 pin, 21 upper
000000632965 18.0 40.1x t1.2n t1.2n generic $60 re-make 1os E-Ton 50cc 2-stroke scooter
Rizzato
12-15 Rizzato 119 engine on Califfo, Atala
000 part# lower @skirt ring1 ring2 maker price 39.4 bore, 12 pin, 15 upper
000000000 23.0 39.32 c2.5n c2.5n generic none original Rizzato Califfo (no rings)
000 part# lower @skirt ring1 ring2 maker price 39.8 bore, 12 pin, 15 upper
000000000 23.0 39.72 c2.5n c2.5n generic $65.0 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. More about this later…
12-16 Peugeot 103 102, Morini MO1 MO2 M1 M101, 90’s Hero
000000 part# lower @skirt ring1 ring2 maker price 39.0 bore, 12 pin, 16 upper
00013001.1074 18.0 38.95 t1.2n t1.2n generic none original Kawasaki AR50
000000 part# lower @skirt ring1 ring2 maker price 40.0 bore, 12 pin, 16 upper
000000069707 17.0 39.88 c2.5i c2.5i Peugeot $70 original Peugeot Sort A
000000069708 17.0 39.89 c2.5i c2.5i Peugeot $70 original Peugeot Sort B
000000069709 17.0 39.90 c2.5i c2.5i Peugeot $70 original Peugeot Sort C (=AA)
000000069710 17.0 39.91 c2.5i c2.5i Peugeot none original Peugeot Sort D (=BB)
000000000000 17.0 39.92 c1.5i c1.5i Asso 00 none original Verona (like MO1), 3mm skirt cut
000000000000 17.0 39.9x c2.0n c2.0n generic none original Hero Pacer, Panther
000000069711 17.0 39.92 c2.5i c2.5i Peugeot $70 original Peugeot Sort E (=CC) most common
000000069712 17.0 39.93 c2.5i c2.5i Peugeot $70 original Peugeot Sort F (=DD)
00000MF553-F 17.0 39.93 c1.5i c2.5i generic $70 re-make MMI for Peugeot
000000069713 17.0 39.94 c2.5i c2.5i Peugeot $70 original Peugeot Sort G (=EE)
000000069714 17.0 39.95 c2.5i c2.5i Peugeot $70 original Peugeot Sort H (=FF)
00000MF553-C 17.0 39.95 c2.5i c1.5i generic $70 re-make MMI for Peugeot
000000069715 17.0 39.96 c2.5i c2.5i Peugeot none original Peugeot Sort I (=GG)
00000069715a 17.0 39.97 c2.5i c2.5i Peugeot none original Peugeot Sort HH
00000069715b 17.0 39.98 c2.5i c2.5i Peugeot none original Peugeot Sort II
000000 part# lower @skirt ring1 ring2 maker price 40.4 bore, 12 pin, 16 upper
000000000000 17.0 40.33 L2.0n c1.5i Asso none original Morini MO4, 3mm sk. cut ASSO 1929MO4
00000023.0125 17.0 40.31 c1.5I c1.5i generic none original Morini MO1,2, 3mm skirt cut says nothing
00000023.0125 17.0 40.32 c1.5I c1.5i Asso none original Morini MO1,2, 3mm skirt cut ASSO.W 2352
00000023.0134 17.0 40.32 c1.5I c1.5i Asso none original Morini M1, zero skirt cut, ASSO W 1929M1
00000023.0134 17.0 40.32 c1.5I c1.5i Meteor $60 generic Morini M1, zero skirt cut,
00000023.0125 17.0 40.32 c1.5I c1.5i Asso none original Morini MO1,2, 3mm skirt cut ASSO 1929
00000023.0125 17.0 40.35 c1.5I c1.5i Asso $70 original Morini MO1,2, 5mm skirt cut ASSO.W 2351
00000023.0136 17.0 40.3x c1.5I c1.5i Asso none original Morini M101 variator engine
000000 part# lower @skirt ring1 ring2 maker price 40.5 bore, 12 pin, 16 upper
000000069716 17.0 40.44 c2.5i c2.5i Peugeot $60 original 1os Peugeot oversize Sort K
000000069717 17.0 40.45 c2.5i c2.5i Peugeot $60 original 1os Peugeot oversize Sort L
000000069718 17.0 40.46 c2.5i c2.5i Peugeot $60 original 1os Peugeot oversize Sort M
000000069719 17.0 40.47 c2.5i c2.5i Peugeot $60 original 1os Peugeot oversize Sort N
000000069720 17.0 40.48 c2.5i c2.5i Peugeot $60 original 1os Peugeot oversize Sort P
000000069721 17.0 40.49 c2.5i c2.5i Peugeot $60 original 1os Peugeot oversize Sort Q
000000 part# lower @skirt ring1 ring2 maker price 40.6 bore, 12 pin, 16 upper
000023.0126/6 17.0 40.53 c1.5i c1.5i Asso $70 original 1os Mor MO1,2, 3mm skirt cut ASSO 1929
000023.0135/6 17.0 40.5x c1.5i c1.5i Asso none original 1os Mor M1, zero skirt cut ASSO W 1929M1
000023.0136/6 17.0 40.5x c1.5i c1.5i Asso none original 1os Morini M101 variator engine
000000 part# lower @skirt ring1 ring2 maker price 40.8 bore, 12 pin, 16 upper
000023.0126/8 17.0 40.72 c1.5i c1.5i Asso $75 original 2os Mor MO1,2, 3mm skirt cut ASSO 1929
000023.0135/8 17.0 40.7x c1.5i c1.5i Asso none original 2os Mor M1, zero skirt cut ASSO W 1929M1
000023.0136/8 17.0 40.7x c1.5i c1.5i Asso none original 2os Morini M101 variator engine
000000 part# lower @skirt ring1 ring2 maker price 41.0 bore, 12 pin, 16 upper
000023.0126/0 17.0 40.90 c1.5i c1.5i generic $70 original 3os Mor MO1,2, 3mm skirt cut says nothing
Peugeot 103
Peugeot and Morini
Morini Pistons Nov 2013
Morini M101
1995 Hero Panther
Morini made a variety of 50cc engines. These pistons shown here are only for 1960’s to 80’s moped-type engines Morini MO, MO1, MO2, M1, MO2 foot shift, MO4, all 40.4mm. They also fit Verona, early Gyromat, and Benelli mopeds, originally 40.0mm, as an oversize. All of the rings and ring pin locations are the same.
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.
12-17 1969-86 Puch, 91-18 Tomos, 74-86 Derbi, 65-80 Benelli
000000 part# lower @skirt ring1 ring2 maker price 36.5 bore, 12 pin, 17 upper
000000229803 18.0 36.43 c1.5n c1.5n Vertex $55 original Tomos MC36 36cc kids dirt bike
000000 part# lower @skirt ring1 ring2 maker price 38.0 bore, 12 pin, 17 upper
000000406300 19.0 37.91 c2.0n c2.0n generic $30 re-make Puch early 2000’s, way too small
000000406300 18.0 37.93 c2.0n c2.0n generic $40 re-make Puch Step II, made small to fit all
0000000037A-C 23.0 37.94 c2.0n c2.0n GOL $60 re-make Puch, made in Italy by GOL
0000000037A-D 23.0 37.95 c2.0n c2.0n GOL $60 re-make Puch, made in Italy by GOL
000000the real 1 20.0 37.96 c1.5n c1.5n generic $55 re-make Puch, made in Taiwan
000000233709 20.6 37.95 t1.5n t1.5n Vertex none original Tomos A55 alu cyl, pre-07 with trap. rings
000000233709 20.6 37.95 c1.5n c1.5n Vertex none original Tomos A55 alu cyl = 37.98 07-09 14140 37.98
000000409000 18.0 37.95 c1.5n c1.5n generic none re-make Tomos A35
000000223747 18.0 37.95 c1.5n c1.5n Vertex $68 original Tomos A35 std, has windows on in side
0000.802.5090 23.0 37.95 L2.0n c1.5n Mahle $70 original Derbi 1976-86 says B
000000 000000 20.5 37.95 c2.0n none Mahle $72 original Puch ’84 alu 37.99 sort C says 38 C 1734
349.110.0069/21 20.5 37.95 c2.0n c2.0n Mahle none original Puch alu cyl 37.98 sort 1 says 38 1 1019
349.110.0069/22 20.5 37.96 c2.0n c2.0n Mahle none original Puch alu cyl 37.99 sort 2 says 38 2 1019
349.110.0069/23 20.5 37.97 c2.0n c2.0n Mahle none original Puch alu cyl 38.00 sort 3 says 38 3 1019
349.110.0069/24 20.5 37.98 c2.0n c2.0n Mahle $65 original Puch alu cyl 38.01 sort 4 says 38 4 1019
349.110.0069/25 20.5 37.99 c2.0n c2.0n Mahle $75 original Puch alu cyl 38.02 sort 5 says 38 5 1019
350.310.0069/03 22.0 37.95 c2.0n c2.0n Mahle none original Puch HT cyl 38.00 sort 11 says 38 1 1116
350.310.0069/04 22.0 37.96 c2.0n c2.0n Mahle none original Puch HT cyl 38.01 sort 22 says 38 2 1116
349.210.5069/11 23.0 37.95 L2.0n c2.0n Mahle none original Puch HT cyl 38.00 sort 11 says 38.0 11 1593a
349.210.5069/22 23.0 37.96 L2.0n c2.0n Mahle none original Puch HT cyl 38.01 sort 22 says 38.0 22 1593a
349.210.5069/33 23.0 37.97 L2.0n c2.0n Mahle $65 original Puch HT cyl 38.02 sort 33 says 38.0 33 1593a
000000 part# lower @skirt ring1 ring2 maker price 38.25 bore, 12 pin, 17 upper
0000.802.5091 20.0 38.18 L2.0n c1.5n Mahle $40 original 1os Derbi 1976-86 says 0.25 B or 0.25 C
0000.802.5091 20.0 38.18 L2.0n L2.0n Mahle $40 original 1os Derbi same but both rings L-type!
0000.802.5091 20.0 38.18 L2.0n c1.5n Mahle $35 original 1os Derbi 1976-86 says 38.205 JG 0.045
349.310.4669/03 23.0 38.19 L2.0n c2.0n Mahle $75 original 1os Puch HT cyl 11 says 38.25 11 1593a
349.310.4669/04 23.0 38.20 L2.0n c2.0n Mahle $75 original 1os Puch HT cyl 22 says 38.25 22 1593a
000000 part# lower @skirt ring1 ring2 maker price 38.4 bore, 12 pin, 17 upper
0000.802.5092 20.0 38.3? L2.0n c1.5n Mahle none original 2os Derbi 1976-1986
000000 part# lower @skirt ring1 ring2 maker price 38.5 bore, 12 pin, 17 upper
000000227334 20.5 38.4x c1.5n c1.5n Vertex none original 1os Tomos A35
000000409001 20.x 38.4x c1.5n c1.5n generic $60 re-make 1os Tomos A35
000000 part# lower @skirt ring1 ring2 maker price 38.7 bore, 12 pin, 17 upper
0000.802.5093 20.0 38.6x L2.0n c1.5n Mahle none original 3os Derbi 1976-1986
000000 part# lower @skirt ring1 ring2 maker price 38.9 bore, 12 pin, 17 upper
0000.802.5094 20.0 38.8x L2.0n c1.5n Mahle none original 4os Derbi 1976-1986
000000 part# lower @skirt ring1 ring2 maker price 40.0 bore, 12 pin, 17 upper
00 70.06.04.00 18.0 39.9x c1.5n c1.5n Asso none original Benelli 1965-80 (old# G7346)
00 70.06.04.00a 18.0 39.95 c1.5n c1.5n GOL $65 re-make Benelli 1965-80
000000000000 19.0 39.94 t1.5n t1.5n Yamaha $60 original Yamaha model? complete
000000 part# lower @skirt ring1 ring2 maker price 40.2 bore, 12 pin, 17 upper
00 70.06.04.02 18.0 40.1x c1.5n c1.5n Asso none original 1os Benelli 1965-80 (old# G7346/2)
000000 part# lower @skirt ring1 ring2 maker price 40.25 bore, 12 pin, 17 upper
000000000000 19.0 40.22 t1.5n t1.5n Yamaha $30 original 1os Yamaha model? without rings
000000 part# lower @skirt ring1 ring2 maker price 40.4 bore, 12 pin, 17 upper
00 70.06.04.04 18.0 40.3x c1.5n c1.5n Asso none original 2os Benelli 1965-80 (old# G7346/4)
Puch
Derbi pre-’87
Tomos A35
Benelli
Tomos A55
12-18 86-89 Derbi, 70-90 Garelli, 72-80 Batavus, 81-89 Trac
000000 part# lower @skirt ring1 ring2 maker price 40.0 bore, 12 pin, 18 upper
0F0.250.0091/A 19.0 39.945 c1.5i c1.5i Mahle none original Derbi 1986-1989 flat reed eng, Sort A
0F0.250.0091/B 19.0 39.95 c1.5i c1.5i Mahle none original Derbi 1986-1989 flat reed eng, Sort B
0F0.250.0091/C 19.0 39.955 c1.5i c1.5i Mahle none original Derbi 1986-1989 flat reed eng, Sort C
0F0.250.0091/D 19.0 39.96 c1.5i c1.5i Mahle none original Derbi 1986-1989 flat reed eng, Sort D
0F0.250.0091/E 19.0 39.965 c1.5i c1.5i Mahle none original Derbi 1986-1989 flat reed eng, Sort E
0000000408211 14.0 39.92 c1.5n c1.5n generic $70 re-make Daelim (Trac) aftermarket (rect. rings)
0000000408201 16.0 39.92 c2.0n c2.0n generic $60 re-make Garelli/Batavus aftermarket
000000 0?????? 14.0 39.9x t1.5n t1.5n generic none original Daelim (Trac) original (trap. rings)
0000000480580 14.0 39.95 c1.5n c1.5n Mahle none original Batavus M48 original says 39.95
0000000080016 14.0 39.9x c1.5n c1.5n Mahle none original Batavus/Trac M56 original Sort A
0000000080017 14.0 39.9x c1.5n c1.5n Mahle none original Batavus/Trac M56 original Sort B
0000000080018 14.0 39.98 c1.5n c1.5n Mahle none original Batavus/Trac M56 original Sort C
0000000080019 14.0 39.9x c1.5n c1.5n Mahle none original Batavus/Trac M56 original Sort D
0000000080020 14.0 40.0x c1.5n c1.5n Mahle none original Batavus/Trac M56 original Sort E
0000000 ?????? 14.0 40.0x c1.5n c1.5n Mahle none original Batavus/Trac M56 original Sort F
00205058.2.150 xx.x 39.9x c2.0n c2.0n Asso none original flat top, Garelli alum cylinder 20, 25mph
00205088.2.150 xx.x 39.9x c2.0n c2.0n Asso none original flat top, Garelli alum. cylinder 30mph
00200001.2.150 16.0 39.9x c2.0n c2.0n Asso none original Garelli iron cylinder 20,30mph
00205053.2.150 17.0 39.9x c2.0n c2.0n Asso none original Garelli iron cylinder 25mph
000000 part# lower @skirt ring1 ring2 maker price 40.2 bore, 12 pin, 18 upper
00200001.2.151 16.0 40.1x c2.0n c2.0n Asso none original 1os Garelli iron cylinder 20, 30mph
00205053.2.151 17.0 40.1x c2.0n c2.0n Asso none original 1os Garelli iron cylinder 25mph
000000 part# lower @skirt ring1 ring2 maker price 40.25 bore, 12 pin, 18 upper
0000000480581 14.0 40.20 c1.5n c1.5n Mahle $75 original 1os Batavus with Laura M48 engine
000000 part# lower @skirt ring1 ring2 maker price 40.40 bore, 12 pin, 18 upper
00200001.2.152 16.0 40.3x c2.0n c2.0n Asso none original 2os Garelli iron cylinder 20, 30mph
00205053.2.152 17.0 40.3x c2.0n c2.0n Asso none original 2os Garelli iron cylinder 25mph
0000000534404 17.0 40.33 c2.0n c2.0n GOL $55 re-make 2os Garelli (made in Italy)
000000 part# lower @skirt ring1 ring2 maker price 40.60 bore, 12 pin, 18 upper
00200001.2.153 16.0 40.5x c2.0n c2.0n Asso none original 3os Garelli iron cylinder 20, 30mph
00205053.2.153 17.0 40.5x c2.0n c2.0n Asso none original 3os Garelli iron cylinder 25mph
000000 part# lower @skirt ring1 ring2 maker price 40.80 bore, 12 pin, 18 upper
00200001.2.154 16.0 40.7x c2.0n c2.0n Asso none original 4os Garelli iron cylinder 20, 30mph
00205053.2.154 17.0 40.7x c2.0n c2.0n Asso none original 4os Garelli iron cylinder 25mph
Daelim (Trac)
Batavus
Garelli
Garelli piston markings
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 1970’s Kreidler Flory, 1990 Honda NS50
000000 part# lower @skirt ring1 ring2 maker price 39.0 bore, 12 pin, 19 upper
13101-GE2-305 16.0 38.94 t1.2n c1.2n generic none Honda NS50 1990
000000 part# lower @skirt ring1 ring2 maker price 39.25 bore, 12 pin, 19 upper
13102-GE2-305 16.0 39.19 t1.2n c1.2n generic none 1os Honda NS50 1990
000000 part# lower @skirt ring1 ring2 maker price 39.5 bore, 12 pin, 19 upper
13103-GE2-305 16.0 39.44 t1.2n c1.2n generic none 2os Honda NS50 1990
000000 part# lower @skirt ring1 ring2 maker price 39.75 bore, 12 pin, 19 upper
13104-GE2-305 16.0 39.69 t1.2n c1.2n generic none 3os Honda NS50 1990
000000 part# lower @skirt ring1 ring2 maker price 40.0 bore, 12 pin, 19 upper
00002150383d 15.2 39.93 c1.5i c1.5i Mahle $80 Kreidler Flory alu cyl 39.98 sort D says R021 40154+
00002150383f 15.2 39.96 c1.5i c1.5i Mahle none Kreidler Flory alu cyl 39.99 sort F says R021 40154+
00002150383h 15.2 39.73 c1.5i c1.5i Mahle $60 (worn used) alu cyl 40.00 sort H says R021 40154+
00002150383m 15.2 39.98 c1.5i c1.5i Mahle none Kreidler Flory alu cyl 40.01 sort M says R021 40154+
12-20 Vespa (Piaggio), 1995-05 Kinetic TFR
part# lower @skirt ring1 ring2 maker price 38.2 bore, 12 pin, 20 upper
182591 16.0 38.12 2.0FG 2.0FG Piaggio $60 original Vespa US ’78-80 Ciao Bravo Grande says USA
191034 16.0 38.1x Dykes 1.5FG Piaggio none original Vespa US ’79-86 Si, ’80-86 Ciao Bravo Grande
part# lower @skirt ring1 ring2 maker price 38.4 bore, 12 pin, 20 upper
Kinetic 16.0 38.30 1.5-3F 1.5-3F generic none original Kinetic ’95-05 (Vespa remake) no arrow
112979 16.0 38.3x 2.0FG 2.0FG Piaggio none original Vespa all ’67-76 Ciao & Boxer, new# is 132521
132521 16.0 38.32 2.0FG 2.0FG Piaggio $50 original Vespa US ’76-78 Ciao, ’77-78 Bravo
182592 16.0 38.32 Dykes 1.5FG Piaggio $65 original 1os Vespa US ’78-86 Ciao Bravo Grande Si says 1M
part# lower @skirt ring1 ring2 maker price 38.6 bore, 12 pin, 20 upper
152381 16.0 38.54 2.0FG 2.0FG Piaggio none original 1os Vespa all ’67-76 Ciao & Boxer, new# is 137681
137681 16.0 38.54 Dykes 2.0FG Piaggio none original 1os Vespa US ’76-78 Ciao, ’77-78 Bravo says 1M
182593 16.0 38.5x Dykes 1.5FG Piaggio none original 2os Vespa US ’78-86 Ciao Bravo Grande Si says 2M
part# lower @skirt ring1 ring2 maker price 38.8 bore, 12 pin, 20 upper
152382 16.0 38.74 2.0FG 2.0FG Piaggio $60 original 2os Vespa all ’67-76 Ciao & Boxer, new# is 137682
137682 16.0 38.74 Dykes 1.5FG Piaggio $60 original 2os Vespa US ’76-78 Ciao, ’77-78 Bravo says 2M
part# lower @skirt ring1 ring2 maker price 40.0 bore, 12 pin, 20 upper
633992 17.0 39.9x 1.2-0F 1.2-0F generic $60 re-make China 49cc two-strokes
20-12 x 38.4 Vespa
20-12 x 38.2 Vespa
20-12 x 40 China
Vespa moped “USA” piston and cylinder
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.
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: All of the Vespa moped pistons below have 12mm wrist pins. There are some (as yet unknown) non-US models with 10mm wrist pins.
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 Minarelli V1L V1HL V1HLE, Suzuki FA50 FS50 FZ50
0000000000 part# lower x = 2, 3, or 4
000000 part# lower @skirt ring1 ring2 maker price 40.3 bore, 12 pin, 21.5 upper
00000004541 15.0 40.2x Dykes 1.5FG Minn. none original Minarelli V1L case reed, all-iron cylinder
00000004543 15.0 40.2x 1.5FG 1.5FG Minn. none original Minarelli V1HL case reed, sleeved al. cyl.
000000 part# lower @skirt ring1 ring2 maker price 40.6 bore, 12 pin, 21.5 upper
00000004551 15.0 40.5x Dykes 1.5FG Minn. none original 1os Minarelli V1L
00000004553 15.0 40.5x 1.5FG 1.5FG Minn. none original 1os Minarelli V1HL, V1HLE
000000 part# lower @skirt ring1 ring2 maker price 40.8 bore, 12 pin, 21.5 upper
00000004561 15.0 40.7x Dykes 1.5FG Minn. none original 2os Minarelli V1L
00000004563 15.0 40.7x 1.5FG 1.5FG Minn. none original 2os Minarelli V1HL, V1HLE
000000 part# lower @skirt ring1 ring2 maker price 41.0 bore, 12 pin, 21 upper
0012110.43000 15.0 40.92 1.5-3G 1.3-3G Suzuki none original Suzuki FA50, FS50, FZ50
000000 part# lower @skirt ring1 ring2 maker price 41.5 bore, 12 pin, 21 upper
12100.35611.050 15.0 41.4x 1.5-3G 1.3-3G Suzuki none original 1os Suzuki FA50, FS50, FZ50
000000 part# lower @skirt ring1 ring2 maker price 42.0 bore, 12 pin, 21 upper
12100.35611.100 15.0 41.9x 1.5-3G 1.3-3G Suzuki none original 2os Suzuki FA50, FS50, FZ50
12 pin, 21 upper, Suzuki FA50
12-22 Minarelli V1, V1H, Sachs 504, 505, Morini S5
000000 part# lower @skirt ring1 ring2 maker price 38.0 bore, 12 pin, 22 upper
000000406500 . 13.5 37.95 1.5FG 2.0FG generic $55 re-make Sachs 504,505 1C,1D says 38
00286-378-051 14.0 37.95 1.5FG 2.0FG Mahle none original Sachs 504,505 1C,1D 553
000000000000 . 16.0 37.95 2.0FG 2.0FG AMF $60 original AMF BHE900 rear engine says 38
00286-378-005 16.0 37.96 2.0FG 2.0FG Mahle $75 original Sachs 504,505 1A,1B 552 says 37.98 G8
0000PC0922D 16.0 37.96 2.0FG 2.0FG Meteor $60 re-make Sachs 504,505 1A,1B Italian made
0000023-0101 16.0 37.93 2.0FG 2.0FG Asso none original Morini S5K, S5K2 says Asso 771
71.0455.0 4500 15.0 37.93 2.5FG 2.5FG Asso $75 original Minarelli V1 1hp 20mph says Asso 825
000000 part# lower @skirt ring1 ring2 maker price 38.2 bore, 12 pin, 22 upper
71.0455.7 4510 16.0 38.1x 2.5FG 2.5FG Asso none original 1os Minarelli V1 1hp 20mph
0000023-0102 17.0 38.1x 2.0FG 2.0FG Asso none original 1os Morini S5K2, can use Minarelli #4510?
000000 part# lower @skirt ring1 ring2 maker price 38.4 bore, 12 pin, 22 upper
71.0455.7 4520 16.0 38.3x 2.5FG 2.5FG Asso none original 2os Minarelli V1 1hp 20mph
000000 part# lower @skirt ring1 ring2 maker price 38.6 bore, 12 pin, 22 upper
71.0455.7 4530 16.0 38.5x 2.5FG 2.5FG Asso none original 3os Minarelli V1 1hp 20mph
00286-378-006 16.0 38.55 2.0FG 2.0FG Mahle $60 original 1os Sachs 504,505 1A,1B
00286-378-052 14.0 38.55 1.5FG 2.0FG Mahle none original 1os Sachs 504,505 1C,1D
000000 part# lower @skirt ring1 ring2 maker price 38.7 bore, 12 pin, 22 upper
71.0406.0 4535 16.0 38.62 1.5FG 1.5FG Minn. none original Minarelli V1 ’78-on-USA
000000 part# lower @skirt ring1 ring2 maker price 38.8 bore, 12 pin, 22 upper
000004540HP 15.5 38.73 Dykes 2.0FG Asso $60 original Demm Smily piston, fits Minarelli
71.0410.0 4540 16.0 38.72 1.5FG 1.5FG Minn. $75 original Minarelli V1 pre-’79-USA, P4 w/iron cyl
0000000034 16.0 38.72 1.5FG 1.5FG GOL $60 re-make Minarelli V1
000000 part# lower @skirt ring1 ring2 maker price 39.0 bore, 12 pin, 22 upper
71.0460.7 4550 16.0 38.92 1.5FG 1.5FG Minn. $75 original 1os Minarelli V1
000023-0133A 15.0 38.94 Dykes 2.0GI Asso none original Unknown, no rings, says Asso 1386
000023-0133A 16.0 38.98 Dykes 1.5FG Asso none original Morini S5R, S5T (alum cyl 1sp kick)
000023-0133B 16.0 38.97 Dykes 1.5FG Asso none original Morini S5R, S5T (alum cyl 1sp kick)
000023-0133C 16.0 38.96 Dykes 1.5FG Asso none original Morini S5R, S5T (alum cyl 1sp kick)
000023-0133D 16.0 38.95 Dykes 1.5FG Asso none original Morini S5R, S5T (alum cyl 1sp kick)
000023-0133E 16.0 38.94 Dykes 1.5FG Asso none original Morini S5R, S5T (alum cyl 1sp kick)
000023-0133F 16.0 38.93 Dykes 1.5FG Asso none original Morini S5R, S5T (alum cyl 1sp kick)
000000 part# lower @skirt ring1 ring2 maker price 39.2 bore, 12 pin, 22 upper
71.0460.7 4560 16.0 39.12 1.5FG 1.5FG Minn. none original 2os Minarelli V1
000000 part# lower @skirt ring1 ring2 maker price 39.4 bore, 12 pin, 22 upper
71.0460.7 4570 16.0 39.32 1.5FG 1.5FG Minn. $75 original 3os Minarelli V1
0000000000 16.0 39.3x 1.5FG 1.5FG Minn. none original Harley Davidson M50 std
000000 part# lower @skirt ring1 ring2 maker price 39.6 bore, 12 pin, 22 upper
71.0460.7 4580 16.0 39.52 1.5FG 1.5FG Minn. none original 4os Minarelli V1
000000 part# lower @skirt ring1 ring2 maker price 39.8 bore, 12 pin, 22 upper
71.0460.7 4590 16.0 39.7x 1.5FG 1.5FG Minn. none original 5os Minarelli V1
000000 part# lower @skirt ring1 ring2 maker price 40.0 bore, 12 pin, 22 upper
0208703.2.150 16.0 39.9x 1.5FG 1.5FG Asso? none original Garelli Monza GT, has port window(s), flat top
000000 part# lower @skirt ring1 ring2 maker price 45.4 bore, 12 pin, 22 upper
71.0485.7 0000 18.0 45.33 1.5FG 1.5FG Minn. $70 original Minarelli 70cc new in box
000000 part# lower @skirt ring1 ring2 maker price 46.0 bore, 12 pin, 21.5 upper
0000023-0140 14.5 45.93 Dykes 1.5GI Asso $70 original Morini 70cc, says Asso W 2508,
000000 part# lower @skirt ring1 ring2 maker price 47.1 bore, 12 pin, 22.5 upper
0000023-01?? 14.5 47.03 Dykes 1.5GI Asso $70 original Morini 70cc, says AW 2666, AA on top
12-22 Morini S5
12-22 x 39 Morini S5
Morini-Minarelli-Sachs connection
Minarelli V1
Sachs 504
.
<Left 1971-79? Morini S5K2 xxxxxxxxxx 23-0101 Ø38.0 22 x 12 x 17
<Right 1972-78 Sachs 504 xxxxxxx 0286.378.005 Ø38.0 22 x 12 x 16
Middle 1969-79 Minarelli V1 20 mph xxxxxx 4500 Ø38.0 22 x 12 x 16
Middle 1951-55 FBM P48, P3, 1956-66 Morini F1, 3M
Connection: Erio Testi worked in his father’s bicycle factory until 1953, when he was sent to Austria, at Fichtel and Sachs, to learn about small two stroke engines. After Testi returned, he transferred the two stroke engine knowledge to his friend Vittorio Minarelli, who was partners with Franco Morini at Fabricca Bologna Minarelli FBM. The two Italian engineers used many of German engineer Ernst Sachs production methods and knowledge, like casting and metallurgy, and design principles, like bore and stroke, port timing, sizes and thicknesses, geometry, etc. Later FBM split into Motori Morini Franco and Motori Minarelli. That’s why early Sachs, Morini, and Minarelli pistons share the same design!
ASSO Pistons
ASSO Factory
ASSO pistons were made in Italy mostly for Italian mopeds. ASSO stands for Assoluta Sicurezza Sempre Ovunque (Absolute Security Any time Anywhere). Early pistons said only “ASSO”, while later 1980’s ones said “ASSO.W”. Somehow ASSO merged with or was acquired by a German name, maybe some “kolben werke” to become ASSO Werke.
12-23 Casal M140 engine on K177, Zundapp?
part# lower @skirt ring1 ring2 maker price 40.0 bore, 12 pin, 23 upper
00Casal 16.0 39.9x c2.0n c2.0n Mahle none original Casal al cyl 39.9x sort D says <–saida D Mahle 401
00Casal 16.0 39.9x c2.0n c2.0n Mahle $70 original Casal al cyl 39.9x sort E says <–saida E Mahle 401
00Casal 16.0 39.9x c2.0n c2.0n Mahle none original Casal al cyl 39.9x sort F says <–saida F Mahle 401
part# lower @skirt ring1 ring2 maker price 48.0 bore, 12 pin, 23 upper
00Casal 16.0 47.9x c2.0n c2.0n Mahle none original Casal al cyl 47.9x sort D says <–saida D Mahle 481
00Casal 16.0 47.9x c2.0n c2.0n Mahle none original Casal al cyl 47.9x sort E says <–saida E Mahle 481
00Casal 16.0 47.9x c2.0n c2.0n Mahle none original Casal al cyl 47.9x sort F says <–saida F Mahle 481
0
Casal Ø40 top
says Mahle 401
Casal Ø48 top
says Mahle 481
Casal (made in Portugal) pistons are made in Germany by Mahle. They say “saida” on top, exhaust side, Portuguese for “outlet”. They 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 2.0 FG gap style, like Garelli.
Indian 4-stroke
13-13 Indian 78-84 AMI-50, 75-77 Honda PC50K1
000000 part# lower @skirt ring1 ring2 maker price 42.0 bore, 13 pin, 13.5 upper
bare E650-00-50 13.5 41.96 1.2flat 1.2flat generic none original Indian AMI50, Hon PC50K1
complete 6131 0 13.5 41.96 1.2flat 1.2flat generic $70 re-make Indian AMI50, Hon PC50K1
000000 part# lower @skirt ring1 ring2 maker price 42.25 bore, 13 pin, 13.5 upper
bare E650-10-50 13.5 42.21 1.2flat 1.2flat generic $45 original 1os In AMI50, Hon PC50K1
complete 6132 0 13.5 42.21 1.2flat 1.2flat generic $70 re-make 1os In AMI50, Hon PC50K1
13-15 Motobecane 1977-80 40, 50, 50V Mobylette
part# lower @skirt ring1 ring2 maker price 39.0 bore, 13 pin, 15.5 upper
22273 21.5 38.92 c2.0i c2.0i MBK $60 Motobecane alu cyl 38.95 sort 2
22274 21.5 38.93 c2.0i c2.0i MBK none Motobecane alu cyl 38.96 sort AA
22275 21.5 38.94 c2.0i c2.0i MBK none Motobecane alu cyl 38.97 sort A
22276 21.5 38.95 c2.0i c2.0i MBK none Motobecane alu cyl 38.98 sort C
22277 21.5 38.96 c2.0i c2.0i MBK $65 Motobecane alu cyl 38.99 sort E
22278 21.5 38.97 c2.0i c2.0i MBK $65 Motobecane alu cyl 39.00 sort G
22279 21.5 38.98 c2.0i c2.0i MBK none Motobecane alu cyl 39.01 sort J
22280 21.5 38.99 c2.0i c2.0i MBK none Motobecane alu cyl 39.02 sort L
22281 21.5 39.00 c2.0i c2.0i MBK $65 Motobecane alu cyl 39.03 sort N
22435 21.5 39.01 c2.0i c2.0i MBK $65 Motobecane alu cyl 39.04 sort P says P
part# lower @skirt ring1 ring2 maker price 39.15 bore, 13 pin, 15.5 upper
22435a 21.5 39.11 c2.0i c2.0i MBK $65 1os Motobecane cyl 39.14 very worn?
14-18 Jawa Babetta 207 series
000000 part# lower @skirt ring1 ring2 maker price 39.0 bore, 14 pin, 18 upper
0000281218a 15.0 38.94 Dykes none Meteor none re-make Jawa 210? 2 x 1 L-ring groove
000000 part# lower @skirt ring1 ring2 maker price 39.03 bore, 14 pin, 18 upper
0000281218A 15.0 38.97 2.0GI 2.0GI Jawa none original Jawa 207, no pin or clips, says A Y
0000281218B 15.0 38.98 2.0GI 2.0GI Jawa none original Jawa 207, no pin or clips, says B Y
0000281218C 15.0 38.99 2.0GI 2.0GI Jawa none original Jawa 207, no pin or clips, says C Y
000000 part# lower @skirt ring1 ring2 maker price 39.28 bore, 14 pin, 18 upper
0000281218/1A 15.0 39.22 2.0GI 2.0GI Jawa none original 1os Jawa, no pin or clips, says 1A Y
0000281218/1B 15.0 39.23 2.0GI 2.0GI Jawa $60 original 1os Jawa, no pin or clips, says 1B Y
0000281218/1C 15.0 39.24 2.0GI 2.0GI Jawa none original 1os Jawa, no pin or clips, says 1C Y
000000 part# lower @skirt ring1 ring2 maker price 39.53 bore, 14 pin, 18 upper
0000281218/2A 15.0 39.47 2.0GI 2.0GI Jawa none original 2os Jawa, no pin or clips, says 2A Y
0000281218/2B 15.0 39.48 2.0GI 2.0GI Jawa none original 2os Jawa, no pin or clips, says 2B Y
0000281218/2C 15.0 39.49 2.0GI 2.0GI Jawa none original 2os Jawa, no pin or clips, says 2C Y
000000 part# lower @skirt ring1 ring2 maker price 39.78 bore, 14 pin, 18 upper
0000281218/3A 15.0 39.72 2.0GI 2.0GI Jawa none original 3os Jawa, no pin or clips, says 3A Y
0000281218/3B 15.0 39.73 2.0GI 2.0GI Jawa none original 3os Jawa, no pin or clips, says 3B Y
0000281218/3C 15.0 39.74 2.0GI 2.0GI Jawa none original 3os Jawa, no pin or clips, says 3C Y
000000 part# lower @skirt ring1 ring2 maker price 40.03 bore, 14 pin, 18 upper
0000281218/4A 15.0 39.97 2.0GI 2.0GI Jawa none original 4os Jawa, no pin or clips, says 4A X
0000281218/4B 15.0 39.98 2.0GI 2.0GI Jawa $65 original 4os Jawa, no pin or clips, says 4B X
0000281218/4C 15.0 39.99 2.0GI 2.0GI Jawa none original 4os Jawa, no pin or clips, says 4C X
Jawa has 3 sorts times 5 sizes
Jawa pistons have 14mm piston pins, thicker than most other 50cc piston pins. There is not a good substitute for Jawa piston, not even one with a smaller pin.
Markings: The marking on top tells the sort (A,B or C) and the size (std or 1,2,3,4).
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 Flandria Bermuda
000000 part# lower @skirt ring1 ring2 maker price 40.0 bore, 14 pin, 24 upper
000000000000 11.5 39.9x 1.5FG 1.5FG Flandria none 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.
4. Piston Information
100’s more vintage replacement pistons of all sizes are in the GOL Pistons Vintage Catalog, a pdf download.