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Technische gegevens Morini V-twin motoren 250/350/500cc
Technical information Morini V-twin engines 250/350/500cc
Identification engine /
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Identificatie frame /
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Performance /

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the 250 single ("½ of the 500")

the 350 V-twin

Motor: Alle modellen: 2 cilinder, 4-takt V-motor, cilinderhoek 72o; rijwindkoeling; hangende kleppen, aangedreven door een tussenliggende nokkenas, stoterstangen en tuimelaars. Tandriem aangedreven nokkenas. Tweevoudig gelagerde krukas. De 250/500/507cc V-twin motoren zijn allen afgeleid van de 350cc V-twin. Daarnaast zijn er ook nog twee ééncilinders gebouwd: een 250cc (een "halve 500cc") en een 125cc (een "halve 250cc"). De verschillen tussen de 350cc Sport en de 350cc Strada motor betreft de compressie (1:11 en 1:10), die bij de Sport bereikt wordt door de toepassing van hogere zuigers. Het tweede verschil betreft de nokkenas. Voor ieder type motorblok 125/250/350/500/507 heeft Moto Morini een andere nokkenas gemonteerd. Lees onderaan deze pagina meer over de verschillende typen nokkenassen.
Engine: All models: 2 cylinder, 4 stroke, V-twin air-cooled engine. Angle between cylinders 72o. All V-twin engines have hanging valves, operated by a camshaft, pushrods and rockers. The camshaft is operated by a toothed belt (or cambelt). The 250/500/507cc V-twin engines were all derived from the 350cc V-twin. Apart from those, also two single engines were built: a 250cc ("half a 500cc") and a 125cc ("half a 250cc"). The differences between the 350cc Sport and the 350cc Strada engines are the compression ratio (1:11 for the Sport, versus 1:10 for the Strada). This is achieved with the Sport by higher pistons. The second difference is the camshaft. For every type of engine 125/250/350/500/507, Moto Morini used a different camshaft. At the bottom of this page you can read more on the various types.


peilstokken open engine engine 3½
Attentie: let op voldoende olie in het blok, want er zijn twee versies peilstokken. Voor een 3½, 3 liter olie !
Attention: make sure your bike's engine has enough oil, because there are two versions of the dip-sticks. A 3½ requires 3 liters of oil !

 Model: 350 T(ouring)
of Strada
350 S
500 V 501

250 V
 Cilinderinhoud: 344cc 344cc 478,6cc 507cc 239cc
 Boring x slag: 62 x 57mm 62 x 57mm 69 x 64mm 71 x 64mm 59 x 43,8mm
35/8200 39/8500 42/7500 42/7600 23/8800
 Topsnelheid: 155 km/u 170 km/u 180 km/u 164 km/u 140 km/u
 Compressie: 10:1 11:1 10:1 11,5:1 11,7:1
 Frame: Dubbel wiegframe Dubbel wiegframe Dubbel wiegframe Dubbel wiegframe (vierkante pijp) Dubbel wiegframe
 Versnellingen: 6 6 5,
>1981: 6
6 6
 Remmen voor: 200mm duplex
>1976: 260mm schijf
230mm dubbel simplex
>1976: 260mm (dubbele)schijf
260mm dubbele schijf 260mm enkele schijf 260mm schijf
160mm simplex 180mm simplex 260mm schijf 260mm schijf 160mm simplex
 Gewicht: 145 kg 145 kg 160 kg 168 kg 130 kg
 Gebouwd: '73 tot '84 '74 tot '81/82 als S
tot '88
als K,K1,K2 Sport
'78 tot '85 '86 tot '92 '80 tot '85
- - - - - -

  )* Voor de Excalibur (chopper) en de Camel (off-road) met 501cc motor gelden andere waarden.

Moto Morini camshafts
Source of the following information: "La Strega", the German Moto Morini magazine, number 33 (autumn 1995).
The article was written by Johannes Schwarzfischer/JSf. JsF agreed with publication on this site.
(The table at the bottom this page is based on factory-information, which was forwarded by German Moto Morini dealer Wolfgang Tritsch).

Camshafts for the 350 Strada and Sport models
The Moto Morini 3½; Strada (or Touring) was introduced back in 1973. The engine of this bike had a "tame" Touring camshaft with a "0" stamped in it. A year later, the Sport model was introduced and the camshaft of this model was stamped with an "S". These letters are stamped in the middle of the shaft and are sometimes bearly visible. Both "0" and "S" camshafts have the same base-diameter of 20mm. The stroke of the "S" camshaft is 0.5mm more than the stroke of the "0" shaft (5.6mm for the S shaft and 5.1mm for the 0 shaft).

Camshafts for the 125, 250 and 500 models
In 1978 both singles 125H and 250T were introduced, as well as the 500T, soon followed by the 500S. The 125 engine became "half" of the Touring ("0") shaft. As you can see in the table, timing of these camshafts are identical, but the cams for the rear cylinder are missing on the 125 camshaft. Also the part of the shaft normally used to fix the pickup was missing as well. This is because the 125 engine has its pickup inside the alternator.
The 500 (478cc) engines got cams with a stroke of 6.4mm (+ 0.7mm), but the base-diameter of the camshaft was reduced from 20mm to 17.5mm. This results in a stroke of 5.95mm for the inlet valve and 5.65mm for the outlet valve. Both 500T and 500S (478cc engine) camshafts are identical. There is no letter indication on this camshaft. The same camshaft can also be found in the 500cc models Camel, mk 1 and 500 SeiV. The 250T engine got a similar camshaft as the 500 (same reduced base-diamenter), but the cams on this shaft are almost identical to the Touring camshaft. Stroke is 5.5mm for both inlet and outlet side. In Germany, in the second half of the

camshaft of the 250T (single)

70s a so-called "27hp class" for motorcycles was introduced for insurance reasons. This was the reason that from 1982 onwards, both 350 Strada (Touring) and Sport models were produced for Germany with identical engines with camshafts of the Touring model. Very similar to the introduction of the 500cc, when both T and S models had identical camshafts. The only difference of the 350 Strada and Sport models in Germany were seat, handlebars, etc. The same Touring camshaft, stamped "0" can also be found in the first Kanguro and even in the 250V !

The 501 engines (507cc)
In 1985, the 501 models were introduced, like the Camel 501 and the 501K (Touring outfit). Again, these bikes had identical engines. Extras on the 507cc engines, compared to the 478cc models, were 28mm carburettors, gilnisil (nicasil ?) 71mm bores and a "sharper" camshaft, the "L5". Letter stamped in the camshaft: "L". The strokes of both inlet and outlet side are identical to the "old' 500, but the angle of opening was increased with 17o. Together with larger valves, this resulted in an engine which would rev. up much easier and also gave more power.
Apparently not enough: in 1988 the timing for the Camel 501 and Coguaro were increased again. This camshaft is also called "L5" but has a different partnumber. It has an openings-angle of 276o, which makes it the "hottest" camshaft for a normal, serial built Moto Morini.
For the 501 Chopper models, the "old" camshaft of the 500 engine was used, but because of the Kokusan ignition, the last part of the camshaft to fix the pickup to was left off. This shaft was stamped "J".
Also the smaller engines were constantly updated in the 1980s. First they had nicasil bores and a new camshaft as well, the "M". This made quite a positive difference to the first 350s of the 1970s. The engine with the "M" camshaft, used in both Canguro as in the 350K is probably one of the best engines of the 350 class. The "M" camshaft was until the end of production the standard camshaft for all 350s. You can find it in the 350 models: Coguaro, Excalibur, New York, Dart and also in the 400cc Dart.

Finally some details
The camshafts used by Moto Morini were not forged, but cast. Cast camshafts are not only cheaper to produce, but technically they are also better. The special steel cast, "sphaero" cast or bullit-graphit cast gives them excellent sliding properties and insures these shafts against quick wearing. It is a fact that camshafts of Morinis with a high mileage have near to new camshafts. The surface of the cams is like they are polished. Also the production tolerance of the camshafts was excellent (max. few /100 of a mm). The timing of new cams vary to a max. of 1 or 2 degrees only.


Nearly every type of engine has it's own camshaft, see the table below for the characteristics

Bench test curves for the 350cc Sport and Touring engines. Output (Bhp), torque (ft/lb) and fuel consumption. Click on image for large format

Print "M" on this camshaft


Type Inlet valve opens Inlet valve closes Outlet valve opens Outlet valve closes GK)1 Hub E/A)2 Valve clearance
to check
cam timing
Running valve
cold engine

Single 125H 12o 42o 42o 12o 20 5.1 1 0.1 ?
250T 14o 44o 44o 15o 17,5 5,5 1 0.1 none
V-Twin 350


Kanguro X1
12o 42o 42o 12o 20 5,1 1 0.1 O
Kanguro X1/X2)* 17o 44o 48o 14o ? ? 1 0.1 E
Kanguro X2
Excalibur, New York
24o 47/49?o 55o 23o 20 5,95/5,75 1 0.1 M
Sport 28o 55o 57o 25o 20 5,6 1 0.1 S
2+2 Race)** 29o 59o 52o 34o 17,5 6,6/5,65 1.0 0.15


V-Twin 250 O 12o 42o 42o 12o 20 5,95/5,1 1 0.1 O
V-Twin 400)*** M 24o 47/49?o 55o 23o 20 5,95/5,75 1 0.1 M
V-Twin 478 - 23o 51o 51o 22o 17,5 5,95/5,65 1 0.1 none
V-Twin 507 L5(I) 33o 58o 58o 32o 17,5 5,95/5,65 1.0 0.15 L
L5(II) 35o 61o 61o 34o 17,5 5,95/5,65 ? ? L
J)**** 23o 51o 51o 22o 17,5 5,95/5,65 ? ? J
)1 "GK" means "Grund Kreis" in German and "basic circle" in English. On certain models, the basic circle of the cams was reduced from 20mm to 17.5mm.
)2 "Hub E/A" means the lift of "E" (inlet) and "A" (oulet) cams.
)* the E camshaft has been found in both genuine Kanguro X1 and X2 models. Later X2 Kanguro's got the type M camshaft (see V-Twin 400).
)** the 2+2 camshaft was produced by the factory for racing and was not a standard cam.
)*** the M cam was fittend on Kanguro X2, Coguaro, 350K, Excalibur 350 and both Dart 350 & 400.
)**** fitted on the Excalibur 501.

(X-1, X-1D and 2+2 cams were fitted on Corsaro Regolarità (125/150/160cc of the 60s/70s).

Type Inlet valve opens Inlet valve closes Outlet valve opens Outlet valve closes GK Hub E/A Valve clearance
to check
cam timing
Running valve
cold engine

(single of the 60/70s)
2+2 Corsaro 52o 78o 75o 56o ? ? 0.25 ? ?
X1 Corsaro 55o 78o 75o 54o ? ? 0.25 ? ?

Part on camshafts: translation German/Dutch: TK. Translation Dutch/English: TK/JS.

The Moto Morini pistons
The pistons used in the V-Twin engines have the combustion chamber "on top", according to the "Heron-principle". The cylinder heads are flat. More technical details will follow. Below pistons of the 350cc engine. Further down this page you can also find details on the 478cc piston.

Pistons of a "Sport" model. The sides are slightly lower compared to "Strada" or "Touring" pistons, as the 350 Sport engine has a higher compression 1:11, versus 1:10

Topview of the Strada piston, which has the make "Sciam" stamped inside, as well as the following number: "785". Apart from the standard size, Morini pistons come in 3 over-sizes: 0.2/0.4/0.6mm. This Strada piston has an over-size of 0.6mm and has a netto weight (without rings) of 192.34 grams.

Again, the topview of the Strada piston, now with an indication to the different heights of the top with the combustion chamber. When we call the level of "area 3" 0, then "area 2" is 3mm higher and "area 1" is 7mm higher. With Sport pistons "area 1" is higher again.

the vertical split allows the piston to expand,
as it get's - with the combustion chamber on
top - rather hot.

on top of the Strada piston you can vaguely see
the "6" stamped in, making it a 0.6mm oversize.

478cc Pistons
478cc piston 478cc piston 478cc piston 478cc piston 478cc piston

the piston of the 478cc engine. Note it has large holes at the front. Further, the shape of the combustion chamber at the top is slightly different to the 350 version.

this illustration shows the top of the 350 piston in the engine.

here you can see that the front and rear cylinder are not straight in line. This sets the cylinders 5cm apart, which helps the cooling of the rear cylinder.

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