Posts

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

Vespa exhaust Exhaust bgm PRO MB Big Box Prototype

Vespa exhaust bgm PRO

NEW: Vespa sports exhaust Big Box Sports

Today we proudly present you the first pictures and the first results of the test bench runs of our new one bgm PRO exhaust systems for the Vespa.

The Vespa Big Box exhaust was developed in close cooperation with MB in England and is also the result of over 20 years Scooter Center Experience.

Advantages of the exhaust:

  • More efficient:
    • powerful like a resonance exhaust
    • significantly easier to turn than SIP Road
    • very wide speed range
    • no performance hole like a reso exhaust
  • Looks like the original
  • Quieter than racing exhaust
  • 200 mm outlet socket with Viton® Oring -> no more cracked exhaust ports on 200 mm aluminum cylinders
  • massive, thick-walled material
  • so far without approval
  • with serial number

Purpose of use:
Due to its original look and its low volume, the exhaust is particularly suitable for original tuning or touring setup.
Due to its power delivery, it can be used universally on original as well as heavily tuned engines at home.

First pictures:
Here are the images of the prototype. The exhaust will be available for the following models:
- Vespa PX 200 / Vespa Rally 200
- Vespa PX 125 / Vespa PX150 / Vespa SPRINT etc.

launch
We expect the exhaust from the beginning / middle of summer and are really looking forward to it. The test drives were great.

Test run performance diagrams:
The exhaust systems were made on the professional Scooter Center Ammerschläger P4 test bench tested with laboratory software:
Result: Significantly more power! eg:

  1. + 2PS more on PX200 compared to the original exhaust with significantly improved revving = top speed
  2. + 3PS more on Malossi 210 compared to comparable road exhaust systems
  3. + 5PS more on Malossi 166 (60mm shaft, exhaust made, 28mm carburettor on rotary valve) opposite Vespa Road exhaust

As the Test roller the following candidates were available:

The test runs were all done with the engine warm. The tests were carried out against the existing exhaust systems on the vehicles and against the SIP Road exhaust.
Almost all scooters were then tested for several kilometers on the road in order to really feel the change. That was the very subjective so-called Popometer test ;-)

The conclusion
Awesome part - this is how a Vespa exhaust has to be!
Both for the "laboratory test" with performance diagram and for subjective testing on the road:
The new bgm PRO exhaust puts you in a good mood. The engine turns out much more freely, the Vespa becomes much more flexible and faster and without the consumption or volume increasing noticeably.

Vespa BigBox Vespa exhaust

Development of a new Vespa exhaust system - the Vespa BigBox from Scooter Center

After we and Mark have brought the Lambretta BIG BOX so far that we can only wait for the manufacturer and, at most, issue reminders, we sent a few sets of PX exhaust shells to Doncaster.

Mark has all of his ideas regarding PX BIG BOX implemented directly after the Eurolambretta. On Monday morning the PX 200 BIG BOX was finally here in the store. A few minutes later the test bench computer started and the games could begin.

Vespa exhaust big box test

It was tested on:

Buy Vespa BigBox here

 

Vespa exhaust performance charts

Here is a small selection of diagrams. Uwe did a lot more runs that we will post over the next few days.