Minarelli P4, P4E, P6 engines



1. 1964 to 1975 Minarelli P4

P4 has a 4-speed, foot-shift, manual clutch, kick start.

 


’64?-65? Minarelli P4V (ovalino)
47.7 cc (38.0 x 42) dome top piston, 2.5 rings
M2-45 carburetor Dellorto SHA 14/12 with F27 cover
A2-11  = 71.0405.0 (o.s. 71.0455.7) piston
A2-8 crankshaft (albero) pork chop with p.p. bushing
A24-10 = 51.0132.7 piston pin bushing ∅12 ∅15 x 13

M2-27 exhaust (scarico) ∅28
M2-5 = 19.0315.0 cylinder ∅38.0 for ∅28 exhaust
M2-40 head (testa)
M2-19 magneto 6V 18w internal spark

 



’65-75? Minarelli P4S (ovalino)

49.6 cc (38.8 x 42) ball top piston, 1.5 rings
M00-00 carburetor Dellorto 12 to 19 mm
A24-31  = 71.0410.0 (o.s 71.0460.7) piston
A24-32 crankshaft (albero) cone ∅13 ’65-70 pork chop
A24-104 piston pin bearing 12 x 15 x 15

M24-21 exhaust (scarico) ∅32
M24-13 = 19.0306.0 cylinder ∅38.8 for ∅32 exhaust
M24-12 = 77.0152.0 head (testa) Sport QUADRO
M00-00 = 77.0161.0 head (testa) Sport RECORD
M2-19 magneto 6V 18w internal spark

P4S changes: Piston pin bushing A24-10 (∅12 ∅15 x 13) changed to needle bearing A24-104 (∅12 ∅15 x 15). The crank changed from A2-8 to A24-32 because the rod end got wider for the new needle bearing. The head changed from small round fins M2-40 to big straight fins M24-12.

This Minarelli P4S engine was on 1969-72 Indian Papoose, JC54 and SE54 (made by Italjet).

’72 Fantic Chopper

’73 Fantic Diablo

In 1967 the company name and logo changed, from F.B. Minarelli to Motori Minarelli. Above in the 1967 ad they showed off their new logo by making it as big as possible, filling an entire page width.

 


Transformation Kits (Serie Transformazoni) with bore ∅41:

’65?-70? P4 Transformation Mini Monza 
55.4 cc (41.0 x 42) flat top piston, L-ring
A24-50 = 71.0475.7 piston
M24-27 carburetor Dellorto UB20S with bell (cornetto)
M24-50 cylinder ∅41.0 (requires a ∅32 exhaust)
M24-51 head (testa)

’65?-70? P4 Transformation Monza 
same as Mini Monza except:
M24-50 cylinder ∅41.0 (requires a ∅35 exhaust)

’65?-70? P4 Transformation Super Monza 
same as Monza except:
M24-55 head (testa) with bigger fins

 


’67 Minarelli Cadetti 60

This late 1960’s Minarelli P4  engine family was intended for racing or sport riding. 

P4 Racing changes: The crank changed from A24-32 (cone ∅13 pork chop flywheel) to A42-100 (cone ∅15 full circle flywheel). The piston changed from A24-31 (dome top 2.5 rings) to A42-102 (flat top L2.0 and 1.5 rings). The carburetor and exhaust got bigger.

’65-70? P4 50 RG Regolarita (regularity)
49.6cc (38.8 x 42) flat top piston, L-ring
A42-102 = 71.0413.0 (o.s 71.0463.7) piston (testa piatta)
A42-100 = 38.0063.7 crankshaft cone ∅15 full circle
A24-104 piston pin bearing 12 x 15 x 15

M24-30 carburetor Dellorto UB20S with filter
M42-111 exhaust (scarico) ∅35 x 320
M42-102 cylinder ∅38.8 Special
M42-208 magneto 6V 18w int. spark, Ducati 31.02.37

’65-71? P4 50 SP Special (Velocita)
same as P4 50 RG Regolarita except for:
M42-107 exhaust (scarico) ∅35 x 300

’65-71? P4 50 CR Cross
same as P4 50 SP Special except for:
M24-30 carburetor Dellorto UB20S with filter
M42-208 magneto 6V 18w int. spark, Ducati 31.02.32 (no lights)

In 1965 a new 60 cc class was launched in Italy to replace the 50 class. In 1970 it returned to 50 cc.

’65-69 P4 60 CA Cadetti (Velocita)
59.2cc (41.4 x 44) piston port induction
A42-203 piston with 6.5mm advance (anticipo)
M24-27 carburetor Dellorto UB20S with bell (cornetto)
M42-211 exhaust (scarico) ∅35 x 295
M42-202 cylinder ∅41.0 Cadetti
M42-208 magneto 6V 18w int. spark, Ducati 31.02.37

’65-69 P4 60 CR Cross 
58.1cc (41.0 x 44) piston port induction
A42-205 piston with 5.5mm advance (anticipo)
M24-30 carburetor Dellorto UB20S with filter
M42-111 exhaust (scarico) ∅35 x 320
M42-202 cylinder ∅41.0 Cadetti
M42-208 magneto 6V 18w int. spark, Ducati 31.02.32 (no lights)

Top: 1965 Italjet Vampiro racer with P4 60 CA Cadetti (piston port induction) engine. The intake goes to the cylinder. The caption says “The Italjet Vampiro with Minarelli 60 engine presented in Monza shortly before the 1965 Milan Show. It will sell for 180 lire including the plastic fairing. Bore and stroke dimensions 41.4 x 44mm = 59.2cc. Note the built continuous double cradle frame and the four-shoe front brake.”

Bottom: 1967 Minarelli factory racer with P4 60 (rotary induction) engine. The intake goes to the crankcase. The caption says “The “lamellar” Minarelli prepared for the 1967 season has the same bore and stroke measurements as the conventionally fueled model, but delivers 9.5 HP at 10,800 rpm against the 9.0 at 10,800 rpm of the “first manner” Italjet which will also be referred to later. It comes from the “lamellar” propeller (rotary induction), with the 17 mm carburetor in direct communication with the crank arm. Always with 4% lubrication.”

In the 70’s and 80’s this engine was incorrectly referred to as a reed valve (lamellare) type, but it did not have a reed valve. Only 60 of these factory racers had this different intake system, according to moto gran premio e 50iniInstead of piston-controlled intake (induction), it had crankshaft-controlled (rotary valve) induction. That’s what Vespa Ciao had since 1968, and Yamaha had since 1961. The reed valve had not been invented yet. It was later invented by Yamaha and first produced in 1973. 

 

’65?-75? P4 60 OM (motor-car)
58.1cc (41.0 x 44) this also had that long stroke crank

 

 


1971 Broncco


’70?-72? Minarelli P4S-70 (ovalino)
66.8cc (45.0 x 42)
A52-4 = 71.0485.7 piston ∅45.0 with dome top 1.5 rings

 

 



2. 1971 to 1985 Minarelli P4E

Minarelli part numbers changed sometime around 1970.

P4E changes: In 1971 the P4E had the following improvements. The ’60’s rounded (ovalino) engine case became ’70’s not-rounded. This first happened with the first P6 in 1969. The pork-chop all-needle-bearing P4S crankshaft became a full circle type like the racer versions had already. Cylinder fins became bigger.

Variations: There were many versions; 5 different cylinders and heads, 5 different kick levers, 8 different  magnetos, 3 different carburetors, and more. 

 

 


 
’71-85? Minarelli P4E (all-iron cylinder)
38.8 bore, 49.6cc ball top piston, 1.5 rings
71.0410.0 (o.s 71.0460.7) = A24-31 piston
15.0029.9 carburetor Dellorto SHA 14/12 with F27 cover
19.0314.0 cylinder EXPORT GHISA for ∅32 exhaust
77.0115.0 head (testa) EXPORT GHISA
38.0063.7 crankshaft (biella) cone ∅15 full circle pp bearing
49.0124.8 woodruff key (chiavetta) #M85 3.0 x 3.6
49.0312.0 flywheel nut (dado) M10-1.25 x 14 hex 15
82.0014.9 magneto
Ducati 31.02.39 2-wire ⇐, ext. spark coil
82.0006.6 points (ruttore) CEV 04229 = M14
82.0132.6 condenser Ducati
∅17.9 = M17T

 

 



’71-80? Minarelli P4E (iron sleeved aluminum cylinder)
38.8 bore, 49.6cc flat top piston, L-ring
71.0413.0 (o.s 71.0463.7) = A24-102 piston
00.0000.0 carburetor Dellorto SHA 14/12
00.0000.0 carburetor Dellorto SHB 19/19B
00.0000.0 carburetor Dellorto SHB 19/19D
19.0002.0 cylinder SP for ∅32 exhaust
77.0110.0 head (testa) NORMALE
77.0111.0 head (testa) SP bigger fins

 


1971-73 P4CS

’71-82? Minarelli P4CS Compact System (iron/alum.)
38.8 bore, 49.6cc flat top piston, L-ring
71.0413.0 (o.s 71.0463.7) = A24-102 piston
00.0000.0 carburetor Dellorto 12 to 19 mm
19.0039.0 cylinder

1974-78 P4CS

1981 Testi Cricket 4M Minarelli P4 engine

1981 Testi Cricket 4M
P4CS-Compact System

 

 

 

 

 

 

 

 


 

’71-82? Minarelli P4R Radiale iron sleeved alum. cylinder
38.8 bore, 49.6cc flat top piston, L-ring
71.0413.0 (o.s 71.0463.7) = A24-102 piston
00.0000.0 carburetor Dellorto 12 to 19 mm
19.0038.0 cylinder

1976 Moto Meteora Minarelli M4 4-speed tubone type frame

1976 Moto Meteora
Minarelli P4R-Radiale

1981 Safari Commando
Minarelli P4R-Radiale

 

 

 

 

 

 

 


 

1973 P4E-70

 
’72?-74? Minarelli P4E-70 iron sleeved alum. cylinder
66.8cc (45.0 x 42)

 

 



3. 1969 to 1985 Minarelli P6

P6 has a 6-speed foot-shift manual clutch. Most were kick start. Some mid-70’s had pedals, for sale in England. 

 


’69-75? Minarelli P6 Sport Quadro (all-iron cylinder)
49.6 cc (38.8 x 42) ball top piston, 1.5 rings
15.0020.9 carburetor Dellorto SHA 14/12 jet 56, cover F27
71.0410.0  (o.s 71.0460.7) piston
M24-21 exhaust (scarico) ∅32
19.0305.0 cylinder ∅38.8 for ∅32 exhaust
77.0152.0 head (testa)

1975 Minarelli P6

1975 Minarelli P6

1975 Fantic 50 Chopper
Minarelli P6 with pedals

 

 

 

 

 

 

 

 

 


 

’71?-85? Minarelli P6R Radiale (iron sleeved aluminum cylinder)
49.6 cc (38.8 x 42)

 

 

 

 

 

 


 

’71?-85? Minarelli P6R Radiale (all-aluminum cylinder)
49.6 cc (38.8 x 42)

 

1976 Fantic RC Casa
P6R all-alum. cyl.

 

 


1973 P6-70

 
’73?-76? Minarelli P6-70 iron sleeved alum. cylinder
66.8cc (45.0 x 42) mostly the same as P4E-70
magneto Ducati 31.02.38 3-wire internal ign. ground
for 1974 Indian ME76 (US model with brake light)

 

 

 

 

 

 


 

page 66, 68 Minarelli P4 P6 magneto, carburetor parts (026 missing)

 

page 70: Minarelli P4 P6 transmission parts, covers, levers, tools

 

 

 

 

 

Minarelli magneto part #’s

M2-25     spark plug Marelli CW 225 = B5HS
11.0132.9 spark plug Bosch W145T1 = W8A = B5HS
11.0133.9 spark plug Bosch W175T1 = W7A = B6HS
11.0134.9 spark plug Bosch W225T1 = W5A = B7HS

82.0001.6 points Bosch         = M31
82.0004.6 points CEV 04221 = M18
82.0006.6 points Ducati        = M14
82.0008.6 points CEV 04229 = M14 

82.0130.6 condenser Bosch          = M32  screw-post
82.0131.6 condenser CEV 7365     = M17
82.0132.6 condenser Ducati
∅17.9 = M17T = modern M17

82.0180.6 greasing felt Bosch
82.0181.6 greasing felt Ducati
82.0182.6 greasing felt CEV 13448

82.0101.6  cam adjuster CEV  MMI 6050

82.0428.6 base plate CEV 13471  80 x 80
82.0429.6 base plate CEV 13373  80 x 94
82.0440.6 base plate Ducati

82.0014.6 stator assy Bosch for 0212.005.027
82.0018.6 stator assy Ducati for 31.02.30, 31.02.39
82.0019.6 stator assy Ducati for 31.02.74
82.0036.6 stator assy Ducati for 31.02.77
82.0038.6 stator assy CEV 04266 for 6932
82.0046.6 stator assy Ducati for 31.12.59
82.0047.6 stator assy Ducati for 31.12.37

82.0202.6 flywheel Bosch 0212.005.027
82.0212.6 flywheel Ducati 31.02.30
82.0214.6 flywheel Ducati 31.02.39
82.0215.6 flywheel Ducati 31.02.74
82.0221.6 flywheel CEV 6948
82.0231.6 flywheel Ducati 31.02.77
82.0233.6 flywheel ⇒ CEV 6932
82.0245.6 flywheel Ducati 31.12.37
82.0252.6 flywheel Ducati 31.12.59

82.0001.9 magneto ⇒ Ducati 31.03.61 2-wire, int spark 6V 18w
82.0002.9 magneto ⇒ Bosch 0212.005.027 2-w, int sp, 6V 18w
82.0004.9 magneto CEV 6931         2-wire, int. spark, 6V 18w
82.0012.9 magneto Ducati 31.02.30 2-wire, ex. spark 6V 18w
82.0014.9 magneto Ducati 31.02.39 2-wire, ex. spark 6V 18w
82.0015.9 magneto Ducati 31.02.74
82.0021.9 magneto CEV 6948
82.0031.9 magneto Ducati 31.02.77
82.0033.9 magneto ⇒ CEV 6932         3-wire, ex. spark 6V 25w
82.0045.9 magneto Ducati 31.12.37
82.0052.9 magneto Ducati 31.12.59