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221cc MALOSSI MHR cylinder for Vespa PX

Malossi MHR 221ccm, new cylinder for the 200cc Vespa with 60mm stroke

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Malossi follows suit with the MHR 221 long-stroke cylinder

After Polini with the Torque hammer 221cc an own Cylinder for their very beautiful 60mm stroke crankshaft, Malossi is also sending a version of the MHR cylinder for 60mm stroke into the race: Malossi MHR 221ccm for Vespa PX and Vespa Rally 200.

In the Scooter Center delivery

We can do that Malossi MHR 221 cylinder already delivering for Vespa 200 and have taken a look at it for you:

 

Malossi 221 002

 

The new flask is immediately noticeable. Here a piston ring keeps the combustion pressure in check. The piston has not undergone any further changes. In the 1-ring variant, the piston ring sits in the same place as the upper piston ring in the 2-ring variant.

The length of the piston skirt is also identical to that of the piston in the 57mm stroke variant. When assembling with a 60mm stroke crankshaft, the length of the piston skirt must also be taken into account with the 221 to avoid hitting the crankcase.

As a replacement for the piston with one piston ring, the normal piston with two rings can also be used.

 

 

Malossi 221 012Malossi specifies a compression ratio of 98,3: 10,5 for the 1mm cylinder, which is slightly longer. The cylinder head is borrowed from the little brothers MHR210 and Sport 210 and is centered with bushings on the cylinder to the bore. We also quickly looked at the heights of the canals. Since the overcurrent channels on the right and left were not identical, we have entered the mean value here as 47,2mm.

 

Malossi 221 007

The outlet width is a good 63% in the green area. The moderate chord size and the large corner radii make the piston ring

make life easy and make the cylinder a permanently reliable service provider even on longer tours.

We are looking forward to the first 221ccm engines with the new MALOSSI MHR 221 cylinder that will appear on our P4!

You can use the new Malossi MHR racing cylinder for your Vespa PX Order here !

The cylinder takes care of:

Vespa

  • 200 Rally (VSE1T - Femsa)
  • 200 Rally (VSE1T - Ducati)
  • What CL 200 (VSR1T)
  • 200 What CLX (VSR1T300)
  • 200 What FL (VSR1T301)
  • 200 PE (VSX1T - 1980)
  • 200 PX E Lusso (VSX1T - 1984-97)
  • 200 PX E (VSX1T - 1981-83)
  • 200 PX E Lusso (ZAPM18 - 1998-)

 

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Details Polini 221ccm cylinder for 60mm stroke

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Polini 221cc cylinder

Update: Malossi MHR 221ccm cylinder for Vespa PX 200 available Malossi MHR 221ccm cylinder

As with the new one Malossi Sport and MHR cylinders , we also dedicate ourselves to the details of the Polini 221cc cylinder for 60mm stroke crankshafts. We had already measured timing & co for the Polini 221 cylinder for the Vespa here: Polini 221ccm 60mm long stroke.

compression

The one included in the cylinder kit cylinder head is also with the current Polini 210cc used. Polini regulates the adjustment of the compaction simply by changing the pinch edge.

So let's grab the head and give it a suitable one Long thread spark plug and simply apply grease as a seal for our plexiglass instrument.

Cylinder head Polini221

With the Plexiglas plate in place, we fill the cylinder head with the burette in order to determine the exact cylinder head volume.

Cylinder head Polini221_2

The meniscus remains in our burette at 25ml. The volume of the combustion chamber in the cylinder head is therefore 25ccm.

To get the entire combustion chamber volume (Vc), we still need the volume of the domed piston crown. With a defined piston backing, in our case 6mm, we first calculate the volume of this “cylinder”.

piston head polini221
6,85 x 6,85 x 0,785 x 0,6 = 22,1ccm so is the volume.

Also sealed with grease and filled with lamp oil in a playful delicate rose, the burette reveals a value of 14,6ccm. So 22,1 - 14,6 = 7,5ccm for the Volume of the piston crown.

3_bottom polini221

The last ingredient is missing Volume of the pinch edge. Measured directly on the living object, i.e. directly on the engine, this is 2,2mm, which in turn has a volume of 8,1ccm requirements.

Combustion chamber volume

So we come to a total combustion chamber volume of:

Cylinder head 25ccm + pinch edge 8,1ccm - piston bottom 7,5ccm
= 25,6ccm

compression ratio

Does this result in a compression ratio? from
Cylinder displacement 221ccm + combustion chamber volume 25,6ccm / combustion chamber volume 25,6ccm
= 246,6ccm / 25,6ccm
? = 9,63

Polini 221ccm cylinder put to the test

Here is another example of the Polini 221 based on a customer engine.

So Polini 221cc, Polini crankshaft 60mm stroke, Dellorto PHBH 28, Polini intake manifold for rotary valve and ours bgm BigBox. With the original cylinder base seal, control angles of 120 ° / 170 ° result. For more information, see the diagram below.

Polini221

For a motor that is only plugged together, i.e. has not undergone any machining of the channel surfaces, 26Nm is a reasonable amount of torque. Especially when power and torque are available that early.

At 4000 rpm, 20Nm are already available, which is at least twice the value that an original PX200 reaches as a maximum.

Depending on the gearbox setting and application preferences, one can confidently longer primary can be used to achieve a solid cruising speed at low speeds on the motorway. The low-vibration running of the Polini crankshaft then contributes to the rest of the comfortable journey ...

120km / h cruising speed

With this motor and a longer reduction ratio should permanent 120km / h to be possible. Here ** as an example, once with the original gearbox and once with our bgm Superstrong clutch and DRT pinion extended by one tooth on the original primary of the PX200 with 65 teeth.

PX200 24_65

Since there are still 7000PS at 20rpm, it is possible to crack the often cited 120Km / h mark.

** The gear calculator "GearCalc" was kindly made available to us by GSF member Motorhead. Thanks very much!

Cylinder -POLINI 221 cc aluminum, 60mm stroke- Vespa PX200, Rally200

Article no. P1400084 http://www.scooter-center.com/product/P1400084

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