From MopedWiki

This is a list of a lot of different moped & scooter engine strokes.

You can use this to see what cylinder matches your engine closely.

37.4mm= Suzuki FA50

37.4 mm = Morini scooter

37.5mm= suzuki katana

37.8mm =suzuki jr 50 (kids dirt bike)

38.0 mm = Batavus Laura M48/M56

38.0 mm = Piaggio/Gilera Hi-Per 2

39.0 mm = Garelli NOI/ horizontal

39.0 mm = Minarelli AM 4 5 & 6 (Shifter)

39.1 mm = Peugeot scooter (Also Fox, Wallaroo and 103)

39.2 mm = Minarelli horizontal LC/AC and vertical scooter. qt50, mj50, lb50 chappy, lc50 champ

39.3 mm = Piaggio scooter LC/AC

39.6 mm = Honda PA50/Hobbit/Camino

39.7 mm = Yamaha DT50MX shifter and Yamaha FS1

39.7 mm = Kreidler shifter

39.7 mm = Sachs 50SW

40.0 mm = Derbi shifter (85 mm conrod length)

40.8 mm = KTM 65 SX

41.4 mm = Kymco scooter

41.4 mm = Honda MT5/NSR50/MTX-sh/MTX-ot/MB5/MBX50/MBX80 shifter

41.6 mm = Kawasaki AR50/80 shifter

41.6 mm = Kawasaki KX65

41.8 mm = Zundapp shifter

41.8 mm = Morini shifter

42.0 mm = Minarelli RV4 shifter

42.0 mm = Sachs 504 and 505

43.0 mm = Gilardoni 43mm stroke cylinder (Minarelli horizontal LC)

43.0 mm = Simonini 80cc cylinder (Vespa)

43.0 mm = Parmakit 80cc cylinder (Minarelli horizontal AC&LC)

43.0 mm = Derbi FDS/FDX shifter

43.0 mm = Puch automatic

43.0 mm = Tomos automatic

44.0 mm = Parmakit 80cc cylinder (Piaggio AC+LC)

44.0 mm = Fabrizi 44mm stroke cylinder (Piaggio LC)

44.0 mm = Simonini 80cc cylinder (Minarelli horizontal LC)

44.0 mm = 2FAST4RACE 44mm stroke cylinder (Minarelli horizontal LC and Piaggio LC)

45.8 mm = Kawasaki KX85

45.8 mm = Simonini 89.9cc cylinder (Minarelli AM6)

46.0 mm = Simonini 90.23cc cylinder (Minarelli AM6)

46.0 mm = Simonini 100cc engine (Vespa)

47.0 mm = Zundapp KS-80 (AC and LC)

48.95 mm = KTM 85 SX

49.0 mm = (Franco) Morini M1 Reed Valve

50.8 mm = MT8/MB8 shifter

54.0 mm = Zundapp KS-175

Original from Puchforum.com

Translated by SchijnHeilig

MBK 51, engine AV10, stock stroke 41.8mm : 49mm = 78,8cc 47mm = 72,5cc 46mm = 69,4cc 45.5mm = 67,9cc 39mm = 49,9cc

MBK 51, engine AV10, long stroke (Malossi MHR crank) 43.8mm : 49mm = 82.6cc 47.8mm = 78.7cc 47mm = 76cc 46mm = 72.8cc 45.5mm = 71.2cc

MBK av10 Gr 2, Gr3, Europe, short stroke 39.7mm 40mm = 49.8cc

Peugeot 103 stock stroke 39.1mm : 50mm = 76,7cc 48mm = 70,7cc 47mm = 67,8cc 46mm = 65cc 45.5mm = 63,7cc 40mm = 49,9cc

Peugeot 103, long stroke (Malossi MHR crank) 43mm : 50mm = 84,4cc 48mm = 77,8cc 47mm = 74,6cc 46mm = 71,6cc 45.5mm = 69,9cc 40mm = 54cc

Puch maxi, stock stroke 43mm : 47mm = 74,6cc 46mm = 71,4cc 45mm = 68,9cc 44mm = 65,3cc 43.5mm = 63,9cc 42mm = 59,5cc 38mm = 48,7cc

Engine Minarelli V1, stock stroke 39.8mm : 53mm= 87.8cc 51mm= 81.3cc 48mm= 72cc 47mm= 69cc 43mm= 57.8cc 40mm= 50cc

Engine Minarelli V1, long stroke (competition) 42mm : 53mm = 92,6cc 51mm = 85,7cc 48mm = 76cc 47mm = 72,8cc 43mm = 60,9cc 40mm = 52,7cc

Engine Minarelli V1, long stroke (competition) 44mm : 53mm = 97cc 51mm = 89,8cc 48mm = 79,6cc 47mm = 76,3cc 43mm = 63,8cc 40mm = 55,2cc

Engine Minarelli V1, long stroke (competition) 54mm : 57mm = 137,8cc 53mm = 119,1cc 51mm = 110,3cc

Sachs 503, stock stroke 44mm : 48mm = 79.6cc 45mm = 69.9cc 38mm = 49.9cc

Tomos A35, stock stroke 44mm : 44mm = 66.9cc 38mm = 49.9cc

Piaggio (all models) stock stroke 43mm : 47mm = 74,6cc 46mm = 71,4cc 43mm = 62,4cc 41mm = 56,7cc 38,2mm = 49,2cc

Piaggio (all models) long stroke (competition) 44mm : 47mm = 76,3cc 46mm = 73,1cc 43mm = 63,9cc 41mm = 58cc 38,2mm = 50,4cc

Engine Simonini Piaggio, bore 48mm x stroke 46mm = 83,2cc Engine Sprocatti Racing Piaggio, bore 50mm x stroke 46mm : 90,3cc