177ccm cylinder bgm PRO for Vespa PX, Sprint and Co

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BGM177 the cylinder for Vespa PX

BGM177 - the new cylinder from bgm PRO

Cylinder -bgm PRO 177 cc- Vespa PX125, PX150, Sprint150, GTR125, TS125, Cosa125, Cosa150

Here we want you the new one BGM177 cylinder imagine the starting April 2016 will be available.


First video BGM177 - the 177 cylinder for Vespa

We showed the cylinder for the first time at the Scooterists Meltdown. The new Online Scooter Magazine SLUK interviewed Philipp and created an exclusive video for our new cylinder:

Suitable for all Vespa 125/150 Largeframe Engines with 3 overcurrent channels.
These include:

  • Vespa PX125,
  • Vespa PX150,
  • Sprint 150Veloce,
  • Vespa GTR125,
  • Vespa TS125 and the
  • Cosa 125/150 models.


Powerful and reliable aluminum cylinder

With the BGM177 we provide you with a powerful and reliable companion.
Many ideas have flowed into the design of the cylinder, so that you can use the cylinder in one as possible wide performance range can use.


Like all modern cylinders, the BGM177 is also made of aluminum.
This has the advantage of very good heat dissipation, which benefits durability, consumption and performance.
A cast aluminum piston with two piston rings works in the extremely wear-resistant nickel-silicon-carbide-coated cylinder bore.

BGM177_8 002


Very light piston

Due to the design and the high silicon content in the material, the piston can be held very light at 193 grams with great thermal and mechanical stability.
This benefits the freedom of rotation and smoothness.
The 1mm thick piston rings are made by a well-known manufacturer in Italy who also supplies leading piston manufacturers such as Vertex and Meteor with high-quality piston rings. The slim rings minimize friction and thus increase performance. In addition, they enable the exhaust duct window to be expanded without any problems.
The piston pin has a biconical design, ie it is thinner at the ends than in the middle. This further helps to reduce the weight of the moving masses.

BGM177_8 011

Aluminum cylinder with ceramic coating and large transfer ports

In the cylinder, the large channel surfaces and the large volume of the overflow channels offer the best basic conditions for a broad performance characteristics and a early onset of torque.

The BGM177 can be combined with simple series components such as the original SI20 carburetor and an original exhaust. This means that the BGM177 already offers a significant increase in performance. The modern design of the cylinder helps him too much low consumption values at the same time high torque from the lower speed range.

Cylinders with great tuning potential

If you are looking for more power, the BGM177 offers sufficient potential and options to achieve the Performance with little effort to raise further. The cylinder reacts very well to a larger carburetor and a supporting exhaust system, such as the bgm BigBox Touring Exhaust system.

The overflow channels in the cylinder base can be expanded very easily. The two large overflow channels on the left and right are only covered by a small sprue in this area. These can easily be opened with a small hand milling cutter. Here, either the cylinder can be adapted to an already revised motor housing or the full duct cross-section can be transferred to a motor housing.

CNC milled cylinder head

The CNC-milled cylinder head is with many cooling surfaces and thanks to the clearance in the middle of the cylinder head, as little heat as possible is bound above the combustion chamber.
In the franking there is also a possibility of a Temperature sensor to assemble. The temperature can be reliably tapped this close to the combustion chamber.
The usual methods, in which, for example, a temperature sensor with an adapter ring is mounted under the spark plug or screwed to a cooling fin on the outside using a thread, do not show any useful values. They only allow you to assess how warm the cooling air near the spark plug or how warm the cylinder head is on the outside of the cooling fin - in our opinion, these positions are simply unsuitable for reliably determining a temperature value. Therefore, bgm uses the positioning very close to the combustion chamber.

BGM177_8 016

Combustion chamber for a wide range of services

The combustion chamber geometry is designed for a wide range of performance. The shape of the combustion chamber cap also allows the use of strong resonance exhaust systems with an appropriately adapted pinch edge. On a 57mm stroke with a touring or box exhaust, the pinch edge can be adjusted to 1mm using the enclosed seals.
If the cylinder is operated with a resonance exhaust and a stroke of 60mm, we recommend that you start with the pinch edge at 1,2mm.

Valve timing 57mm

On a motor with a 57mm stroke you will achieve the following values ​​with a pinch edge of 1mm:

  • Compression 10,3: 1
  • Overcurrent angle 118 °
  • Outlet angle 171 °

The large length of the cylinder enables the cylinder head to be centered in the bore of the cylinder with a 4mm thick shoulder. Due to the shoulder, the cylinder head gasket is still perfectly centered even in the event of a stroke change and cannot stand in the combustion chamber. If the stroke is changed to 60mm, the cylinder can also be raised further, depending on the planned motor concept, in order to achieve significantly larger overcurrent angles.

Valve timing 60mm

On a motor with a 60mm stroke, the following values ​​are achieved with a pinch edge of 1mm:

  • Compression 10,8: 1
  • Overcurrent angle 123 °
  • Outlet angle 173 °

The outlet width is 42mm (66%) and therefore offers good conditions for a high-revving engine even with short control angles.

BGM177 vs PX 200 12hp

Plug & Play with a lot of power

Here is a comparison between a BGM177 and a standard Rally200 with 12PS Piaggio cylinder (comparable to a Vespa PX200 GS).

The BGM177 cylinder is unchanged in this attempt and is on a Sprint Veloce engine.
The inlet, crankshaft and ducts in the engine have not been machined.
Only one SI24 carburetor the 200cc model was assembled without adjusting the carburetor pan or the engine housing, as well as with a BGM BigBox Touring combined.

The spraying is very much based on the original 200ccm equipment:
Main air correction nozzle: 160
Mixing tube: BE3
Main jet: 125
Idle nozzle: 55/160
Air filter: standard (without additional holes)

The pre-ignition was set to 19 ° BC. set.

The broad power range (smooth lines) and the high available torque (dotted lines) from idle can already be seen very nicely on this not further optimized engine.


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In the next article we will then deal with increasing the performance of the cylinder. An LML membrane motor will serve as the basis for this.


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