Morini Engine Models

Table of Contents

1. 1950’s   47.7cc     2,3-speed vert. all-iron cyl. ∅38.0          P48, P3 (FBM)
1. 1950’s   47.7cc     2,3-speed vert. all-iron cyl. ∅38.0           2M, 3M
2. 1960’s   47.7cc  1,2,3-speed vert. all-iron cyl. ∅38.0  F48, 2M, 3M, 2B, 3B
3. 1960’s   49.6cc   3,4-speed vert. all-iron cyl. ∅38.8
  3CV, 4MP, 4MP-S, 4CL-S
4. 1970’s   49.0cc    1, 2-speed horiz. cylinder     ∅40.0  Gyromat, Convert
4. 1970’s   49.0cc  1,2,4-speed horiz all-iron cyl. ∅40.0  MO, Convert, MO4

4. 1970’s   49.9cc1,2,4-speed horiz. cylinder     ∅40.4  MO1, MO2, MO4, Gyrokick
4. 1970’s   49.9cc1,2,4-speed horiz all-iron cyl. ∅40.4  MO1, MO2, MO4, Gyrokick

5. 1970’s   47.7cc    one-speed vert. all-iron cyl. ∅38.0  S5K, S5K2
5. 1970’s   49.55cc  one-speed vertical cylinder  ∅39.0  S5R, S5E

6. 1980’s   49.9cc1,2,3-speed horiz. cylinder     ∅40.4  M1, M101, M1K, MO3
6. 1980’s   49.9cc    one-speed horiz all-iron cyl. ∅40.4  M1, M1K

7. 1980’s   49.55cc  one-speed vert all-alum cyl  ∅39.0  S5N, S5T

8. 1990’s   49.9cc    one-speed horiz. cylinder     ∅40.4  M1K
9. 1990’s   49.55cc  one-speed vert all-alum cyl  ∅39.0  S5GS





1. 1950’s 50-70cc 2, 3-speed vertical-cylinder engines


1954 FBM P3 kick start
47.7 cc (38 x 42) 3-speed

1954 FBM P48 pedal start
47.7cc (38 x 42mm) 2-speed

The first Morini and Minarelli engines in 1956-58 were mostly the same as 1954-55 Moto FBM. These 1950’s models have very rounded head fins.

1956? Morini 2M 2-speed hand-grip-shift
47.7 cc, 38.0 mm bore, 42.0 stroke










1958? Morini 2M pedal start
47.7 cc (38 x 42) 2-speed hand-shift









1960 Morini 70cc 3-speed foot shift











2. 1960’s 50cc 1, 2, and 3-speed vertical-cylinder engines

1961 Morini F48 1-speed with pedals

50’s look: The 1956-61 Franco Morini F48 1-speed looks like it’s predecessor, the 1954-55 Moto FBM P48 Pettiroso 2-speed. It has the rounded 1950’s head fins. But the F48 has no shift cable attachments and no foot shifter. That distinguishes it from the others that change gears. Otherwise it looks the same.

It is not yet known if the 1961 Morini F48 was automatic clutch or manual clutch (or both). Both types have clutch cables, and look the same on the outside. By 1968 it was automatic.

New logo: The earliest photo of the hourglass logo was this F48 from 1961.


Newer fins: The 1962-66 50cc motors below have the 1960’s style head fins, taller in front and less rounded (except for fan-cooled types). The shape of the cooling fins and engine case can indicate the year range. Newer fins are bigger and more square, less rounded. Newer engine cases are less rounded. 

1962? Morini 3M
3-speed hand-shift, 48cc, 55km/h
Dellorto T4 12 S1 carburetor (12mm)
47.7 cc, 38.0 mm bore, 42.0 stroke

1962? Morini booklet

1962? Morini F48 (pedals)
1-speed manual clutch 48cc, 40km/h
Dellorto T4 9 S1 carburetor (9mm)
47.7 cc, 38.0 mm bore, 42.0 stroke














1963? Morini 3M (pedal version)
47.7 cc (38.0 x 42.0) 3-spd hand-shift
export version 1.4 hp 40 km/h
Dellorto SHA 14/9 carb (9mm)

1964 Morini 3M (pedal version)
47.7 cc (38.0 x 42.0) 3-sp hand-shift
normal version 2.2 hp. 50 km/h
Dellorto SHA 14/12 carb (12mm)

1964 Morini 3M series













1964 Morini 3M parts
export version 1.4 hp 40 km/h
47.7 cc (38.0 x 42.0 mm)

1964 Morini 3M parts
clutch and transmission
47.7 cc (38.0 x 42.0 mm)

1964 Morini 3CV parts
(parts different from 3M)
49.6 cc (38.8 x 42.0 mm)
















1965 Morini 3CV fan-cooled 
3-speed foot-shift, kick-start
49.6 cc (38.8 x 42.0 mm)

1968 Morini 3 MCL/SP 49cc 3.8hp kick-start
3-speed grip-shift, Dellorto racing type carb












3. 1960’s 50cc 4-speed vertical-cylinder engines

1967 Morini 4 CLS 49.6 cc 4 hp kick-start
4-speed foot-shift, fan-cooled sport bike

Some time in the mid-1960’s, starting with the 3CV, the bore increased from 38.0 to 38.8mm. The piston and rings got bigger, but the rings also got thinner.

1969 Morini 4 MP/S Turbo
50cc 5 hp 4-speed foot-shift

1967 4 MP/S Turbo









1967? Morini 4 MP/S Turbo parts view
4-speed foot-shift kick-start
49.6 cc, 5 hp, 38.8 mm bore, 42.0 stroke


1972 Morini P4/S 49.6 cc 3.5?hp 4-speed














4. 1970’s 50cc 1, 2-speed horizontal cylinder engines

It’s hard to find info about these. Like other Morini and Minarelli engines, the engine identity is concealed or replaced with the bike maker name. The bike maker flyers are the best source of official photos and information.

1968 Morini ??? horizontal cylinder
49.0 cc (40.0 x 39.0) 1-spd manual clutch, 7.5 cr
1970-type aluminum cylinder steel sleeve 40.0
normal version 1.4 hp. 40 km/h
Dellorto SHA 14/12 carburetor (12mm)

1968 Malaguti line

The first horizontal-cylinder Morini one-speed moped engines were not automatic. The 1968 Malaguti flyer shows this. The Dribbling model with horizontal cylinder says “monomarcia” (one speed), while the Nuovo Europino vertical cylinder model says “monomarcia a frizone automatico” (one speed automatic clutch).  

1970-type aluminum cylinder: The late 60’s and early 70’s horizontal aluminum cylinders with all-horizontal fins, have a standard bore of 40.0 mm. 

iron cylinder: These cylinders are cast iron, darker, heavier, with top and bottom fins vertical and side fins horizontal. From the front view, the fins resemble a very thick plus sign. This all-iron cylinder replaced the 1970-type iron-sleeved aluminum cylinder in the early 70’s. At first in the early 1970’s the iron cylinder had a 40.0 mm standard bore, so it would interchange with the 1970-type. Later in the mid-1970’s it had a 40.4 mm standard bore, so it would interchange with the 1977-type. But not all changed to 40.4 in the mid 70’s. Some remained 40.0 bore into the late 1970’s. Some late 1970’s owners manuals specified 40.0 mm bore: 1976 NVT Easy Rider ER1, ER2, 1977 Intramotor-Gloria Scout. Most others of this period specified 40.4 mm. 

1977-type aluminum cylinder: These were iron sleeve aluminum cylinders with bigger fins, thicker plus sign style. They were made from the early 1970’s to about 1980. Most have a 40.4 bore, but some might have been made with 40.0 bore. That is what is shown and stated in the manuals mentioned above. Maybe 1 out of 10 Morini 1977-type cylinders on US models are 40.0. About 9 out of 10 are 40.4.


1969? Morini Gyromat, horiz. cyl with pedals
49.0 cc (40.0 x 39.0) 1-speed automatic, 7.5 cr
1970-type aluminum cylinder steel sleeve 40.0
normal version 1.4 hp. 40 km/h (26 mph)
Dellorto SHA 14/12 carburetor (12mm)

Gyromat: In about 1969 a new series of engines began, called Gyromat. These were pedal-start horizontal-cylinder one-speed automatic clutch Franco Morini moped engines.

Convert: In the mid-1970’s Morini developed a two-speed automatic version of the Gyromat, called the Convert. A Morini Convert is the precursor of the Morini MO-2.

Gyrokick: In the mid-1970’s Morini produced a kick-start version of the Gyromat, called the Gyrokick. 

1972? Morini Gyromat
1-speed automatic, pedals
1970-type alum cylinder 40.0

1975? Morini Convert
2-speed automatic, pedals
iron cylinder 40.0 or 40.4








1973? Malaguti Duomatic
same as Morini Convert
1970-type alum cylinder 40.0

1972? Itom Automatic
same as Morini Gyromat
1970-type alum cylinder 40.0

1976? Morini Gyrokick  horiz. cyl, kick-start
49.9cc (40.4 x 39.0) 1-speed automatic, 7.5 cr
1977-type aluminum cylinder steel sleeve 40.4









1976 Morini Gyromat MO1
iron cylinder 40.0 or 40.4

1978 Morini Gyromat MO1
1977-type alum cylinder 40.4


1978 Morini MO1
1977-type alum cylinder 40.4













Morini MO and MO1




20-0012 inner side

20-0012 with 13-5031

20-0012 outer side












Morini Pistons Nov 2013















Morini MO2




MO1 and MO2 Speed Versions – Differences

30mph 2.2hp 13T sprocket, 14/12 carb, Ø13 intake, same cylinder, 5mm piston skirt cut
25mph 1.4hp 12T sprocket, 14/12 carb, Ø12 intake, same cylinder, 3mm piston skirt cut
20mph 1.0hp 12T sprocket, 14/ 9  carb,  Ø9  intake, restricted cyl., 3mm piston skirt cut






1975? Morini MO4 horiz. 4-speed foot-shift
49.0 cc (40.0 x 39.0) 1-speed automatic,
iron cylinder 40.0 or 40.4 bore

1970 Morini MO4 horizontal 4-speed on Cimatti Mini Chic
49.0 cc (40.0 x 39.0) 1-speed automatic, foot-shift,
1970-type aluminum cylinder steel sleeve 40.0 bore
Dellorto SHB 18/15 carburetor (15mm)
Dansi magneto ⇐ MSL 168 7936B/63













5. 1970’s 50cc 1-speed vertical cylinder engines

1968-72 Morini S5K, 1-speed automatic 47.7cc (38.0 x 42.0)
from 1972 Indian JC5A, MM5A Parts Manual

S5K: The 1968? to 1972? Morini S5K had the same cast-iron cylinder and piston and head from the early 1960’s. The connecting rod had a brass bushing for the piston pin. The right-side kick start operates backward.  

1970 Morini S5K  1-speed automatic
backward kick, 47.7 cc, 2.2 or 1.4 hp
38.0 bore, 42.0 stroke, 6.5 comp. ratio












MF logo: The above logo says MF (Morini Franco), very stylized, and very 70’s, all straight lines.

S5K2: The 1972? to 1978? Morini S5K2 has improvements over the S5K. It has a needle bearing for the piston pin, instead of a brass bushing. It has a right-side kick start lever that operates forward, with an external return spring and improved mechanism.

Manufacturers that have used this 1970’s S5 engine, or the 1980’s to late 1990’s S5 versions, are as follows: Italjet/Indian, Malaguti, LEM, KTM, Husqvarna, DBM, Young Rider plus many others.

1974 Morini S5K2 1-speed 
47.7 cc automatic, forward kick
38.0 bore, 42.0 stroke, 6.5 cr
normal version 2.2 hp. 50 km/h
Dellorto SHA 14/12 carb (12mm)

1972-78? Morini S5K2, 1-speed automatic 47.7cc (38.0 x 42.0)
from 1974? Italjet M5A Parts Manual with 1978 late items added















1974 Morini S5K2 1-speed 
47.7 cc automatic, forward kick
38.0 bore, 42.0 stroke, 6.5 cr
slow version 1.4 hp. 40 km/h
Dellorto SHA 14/9 carb (9mm)

Left, 1972?-78? Morini S5K2
Mid 1969-79 Minarelli V1 1hp 
Mid 1951-55 FBM P48, P2, P3
Mid 1956-68? Morini F1, P3 Right, 1972-78 Sachs 504
All are 38mm and interchange.


Sachs design: The S5K2 piston is an old design used by Morini and Minarelli since before their beginnings. It is 38.0mm diameter, very tall (22mm) above the wrist pin (12mm) and short below (17mm). But why are these early Italian 50cc pistons the same dimensions and design as German pistons made by Sachs?

In the early 1950’s Vittorio Minarelli visited Fichtel and Sachs in Austria to learn about moped engines. When Minarelli returned he began building engines, along with partner Franco Morini, at FBM in the 1950’s. The 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.






1979 Morini S5E

Morini S5E and S5N, 1-speed automatic 49.6cc (39.0 x 41.5)








S5E, S5R piston 23-0133D








1978 Morini S5R “radiale” engine
49.6 cc 1-speed automatic, aluminum cylinder
39.0 mm bore, 41.5 mm stroke, 9.0 comp ratio
5.0 horsepower, Dellorto SHB 19/19 carb


S5E: In the late 1970’s the S5E “Electronic” replaced the S5K2. It had an electronic ignition system instead of points ignition system. The S5E still had a cast iron piston-port cylinder, but the fins were bigger and completely square, like a 70’s Volvo! The piston changed from a 1950’s design 38mm with two thick rectangular (regular) rings, to a late-70’s 39mm with upper L-type (Dykes) ring. The crankshaft changed from 42mm stroke to 41.5, and the piston pin small brass bushing became a bigger needle bearing. Other things changed, like the forward-kick lever became aluminum. But the rest of the S5E engine and transmission remained mostly the same as S5K2. This is apparent from the illustration. 

S5R: In the late 1970’s the S5R “Radiale” was a sport version of the S5E. It had a piston-port aluminum cylinder with very big fins and a distinctive radial-fin head.  The exhaust header pipe passed through the right side engine fins. It had a bigger carburetor and intake manifold than the S5E. Serious power for an 8-year-old, without any gear shifting!



6. 1980’s 50cc 1, 2-speed horizontal cylinder engines

M1: In 1979 Morini came out with the M1 engine, a one-speed with a case-type reed valve. The reed valve induction produced about 20-30% more torque. The result was acceleration about the same as a MO-2 two-speed, but at a much lower cost and complexity. So by about 1980, both the MO-1 and MO-2 were discontinued in favor of the M1.

Morini M1





M101: In 1981 the two-speed M101 came out, a variator-transmission belt-drive engine with a M1 top-end (cylinder, piston and head). The variable-ratio-pulley transmission resulted in increased acceleration over the fixed-ratio M1. The price increased and so did the weight and case length.

Morini M101




1983 – 1985 Morini MO3
3-speed cable-shift, kick-start












7. 1980’s 50cc 1-speed vertical cylinder engines

Morini S5N

Morini S5E, S5ET, S5NG, S5NG4

Morini 1980’s – 90’s S5 pistons









S5N: In the early 1980’s the S5N replaced the S5E. The S5N had an aluminum piston-port cylinder, lighter in color but with the same fins. The piston design changed from L-type upper ring to both rectangular thin 39 x 1.0. The thin rings made better compression at high rpm.

S5T: In the mid 1980’s the S5T replaced the S5N. The S5T had a reed valve in the cylinder, and much bigger cooling fins. With the reed valve the intake air mixture can flow through a window in the back side of the piston, and the cylinder can have additional transfer ports on the intake side. Those benefits outweigh the extra restriction of the reed valve.

Morini S5T, reed-valve cylinder

Morini S5T















8. 1990’s 50cc 1-speed horizontal cylinder engines

The Morini M1 was still in production in the 1990’s




9. 1990’s 50cc 1-speed vertical cylinder engines

Morini S5GS

Morini S5GS

S5GS: In the early 1990’s the S5GS replaced the S5T. It had larger cooling fins, larger carburetor, and a bigger reed valve with more reed petals, 4-reed instead of 2-reed.

Manufacturers which have used this engine include: Husqvarna, KTM (pre 2001), LEM, Rivara and DBM. The Husqvarna version of this engine was fitted with an O-ring head gasket & thicker base gasket in later years.