7 On the Road - Vespa bgm Platónika project by Scooter Center
How we would say in Colombia: now I’m on my Salsa“ (what means I am in my element). I received Platónika with 18 km on the clock and exactly 15 days later, she had thousand kilometers more.
Excited because the spring is arriving, I started to ride, and even prepare a Moto Nostra Kit for better touring:
But with this German weather you never know.. Indeed the following week it started to snow… But that wouldn’t stop me, so I protect myself against the nasty cold and go on.
Photos and videos come and go, but still, I think, I am beginning to miss something, the reason of why I fell in love of with this scene: That’s right! The Vespisti.
Without any meeting in sight, „I will roll with my team mates“ I thought, so I turn my head around in the marketing office, where I am, and I only saw two Lambretta people…
And well… why not?
Did you miss a chapter? here you find the complete Story:
Platónika Projekt - die komplette Geschichte - Vespa PX bgm 177 by Scooter Center
https://blog.scooter-center.com/wp-content/uploads/2021/04/Yz-on-the-road.jpg9321440Maryzahttps://blog.scooter-center.com/wp-content/uploads/2023/08/SC_BLOG-300x69.pngMaryza2021-04-16 10:55:282021-04-16 10:55:287 Project Platónika – On the road
The Vespa engine – the heart of Platónika – has received the desired control angles of the crankshaft in the last article
Cylinder transfer ports in the engine adapt for performance optimization
Before the complete assembly of the motor can be done, all work that generates chips must be done. Only then can the housing be cleaned.
In the next step, this includes the ports of the cylinder in the engine.
The BGM177 is designed in such a way that the cylinder functions perfectly even on the original ports.
However, in our project we took the opportunity to directly adapt the case. A better filling of the cylinder always means a higher possible torque.
In order to transfer the contour of the overcurrent channels to the motor housing, the easiest way is to place the matching cylinder base gasket on the housing and thus transfer the contour to the housing.
A milling cutter is then used to adapt the contour in the motor housing. It is not necessary to mill the channel exactly as deep as in the original motor housing.
The BGM 177 cylinder is designed from the basic construction so that the piston offers a sufficient cross section.
The generated surface of the adapted channel may be milled rough. Further polishing is not necessary. As long as there are no more rough corners and edges, a slightly roughened surface is perfect.
After the channels have been milled and the housing has been cleaned again, the assembly process continues
Scooter Center Tutorial Vespa PX - Modifying the transfers (activate subtitles)
In the last episode of Platónika we showed you what kind of parts has been selected.
Now it’s time for some visual petting!
To my surprise and during the same day I suddenly had a whole scooter in boxes, ready to be assembled. A big thank to the more than effective team in the warehouse here.
But … what do you do when that desired package arrives? Exactly, unpack everything.
That is how it turns out with thousand of pieces all over the floor and we have no option but to accept the #tetrischallenge, see here the video of this exploded view in the real life.
Exploded view Vespa px bgm 177 - Project Platónika by Scooter Center
Hello I’m Maryzabel and I do part of the Scooter Center team. In the SC Newsblog I will show you my adventures here and give you a look behind the Scenes.
My final trainee step brought me to the technical department. So I had to put away the notebook and put on the work gloves. Additionally to the technical work, I will also do some video footage on the work that we do.
One idea of me was to restore a Vespa Smallframe so that I get back on a Vespa gain instead of using the public transport. With everyone very passionate about scooters, they instantly liked the idea. After some head scratching about the state of my Smallframe, the technicians came up with another idea. Why not build a scooter from scratch. ALL YOU NEED for that is here and the plan was to use one of the LML frame sets and combine it with an engine with the full bgm treatment. The imagination started and everybody was hooked by the idea.
So we are now not only going to build the Vespa of my dreams, we will also do un-boxing videos, reviews and tutorials.
And for sure we will show you the build of the Vespa step by step. She will be a platonic love.
Here we have the teaser of the things to come.
TEASER - Vespa Project Platónika - Building a Vespa PX bgm 177
https://blog.scooter-center.com/wp-content/uploads/2016/10/this-is-177.gif250970Emanuela Lucatuortohttps://blog.scooter-center.com/wp-content/uploads/2023/08/SC_BLOG-300x69.pngEmanuela Lucatuorto2016-10-13 12:58:192016-10-13 13:01:24bgm 177 / 187cc cylinder kit for Vespa back in stock
We have already presented the new cylinder in this post. Today we would like to offer you an insight into developing this cylinder. The cylinder will finally be available from beginning of April 2016!
Developing the Vespa cylinder BGM177
Developing a two-stroke cylinder is very exciting.
Numerous parameters, which need to be considered, thousands of times on the dynamometer, a repetition of measuring, calculating, testing, thousands of kilometres on the road…
What for? To have a final cylinder, which offers high torque and is willing to deliver maximum performance, at the same time resistant with a low consumption.
And we want it all. A cylinder for tourers, which can be combined with standard components, and for ambitious tuners, who want the highest performance possible. It is about offering the widest range possible.
We would like to give you an insight in the tests, which have been conducted for the BGM177.
DESIGN OF TRANSFERS
We tested various options for the outer design of the transfer ports.
We designed various transfer geometries, trigger delay angles and combustion chambers, which were put to practical tests on the road as well as on the dynamometer.
TEST ENGINES SPRINT150
We have been using an original Piaggio Sprint engine as starting point for our tests and for some we also have been using a LML engine casing with original inlet membrane control.
The Sprint engine casing represents the very small, original rotary valve inlet of largeframe engines. The rotary valve inlet of a PX125 is only minimally larger than the inlet of Sprint engines. Trigger delay angles of the crankshaft are almost the same. In terms of possible performance, this was the “least attractive” package. However, we wanted to know the performance with basic parts or rather which performance we could expect of the rest.
We have already presented the comparison of a Spring engine with a 24mm SI carburetor of a PX200 and a 12HP 200 engine.
In order to easily understand the following graph, just imagine a normal PX200. With a standard 200cc you will feel something like acceleration up to a speed of about 90km/h. This speed represents about 5500min?¹ of the engine. Once you have reached this torque with a 200cc engine, it will take some time to get to 100km/h (6000min?¹). Now, take a look at the graphs and compare the equivalents of this torque on the blue graph and the red graph. You will see, that the BGM177 even adds more torque. In other words, while a 200 is slowly running out of steam, the BGM177 will continue to accelerate.
BGM177 vs. PX200
TEST ENGINE LML150 MEMRANE
The 125cc engine of a Vespa Sprint with small rotary valve restricts the development of performance at a certain level of performance and torque. We have therefore used a LML engine casing for varying tests and comparisons. The standard LML engine casings comes with a reed valve intake and large transfer ports in the casing and is the best basis. This can diminish the influence of e.g. an intake, which is too small, or differently designed transfer ports on the test results within one series of tests.
It’s also fairly easy to switch between a SI carburetor and a large, grown-up intake.
We have started these tests with a pre-series cylinder with small transfers in the cylinder base
and a piston, which has been specially produced for this test.
Why? We wanted to find out how the piston needs to be designed in order to give enough room to the transfer ports to guarantee a good situation. The piston had been constructed in a way, that the hole around the gudgeon pin close to the transfer ports could be adapted by milling.
After every little step, we put it to the test on our dynamometer to find out, which shape or which combination works best.
TEST TRANSFER PORT CROSS-SECTION CYLINDER BASE
The following series of tests has been conducted on a LML membrane engine with a 24 SI carburetor, a BigBox Touring and various versions of pistons and transfer ports.
Then, the cylinder head has still had a relatively high compression. We have reduced compression of the standard cylinder head a little to gain a wider range of performance.
The original test piston was shaped like the original PX piston. So, for the red graph, the piston skirt was closed (like for a Piaggio, Polini, Grand Sport, …).
The blue graph shows the result of the piston with a few millimetres less around the gudgeon pin. You can see such a piston on the picture above.
The green graph shows the performance with a semi-closed transfer port at the cylinder base and an adapted piston. The free space of the transfer ports in the cylinder base represents about 80% of the possible space of the cylinder.
RED GRAPH: closed piston skirt
BLUE GRAPH: semi-closed piston skirt
GREEN GRAPH: opened piston skirt
Result: the BGM177 can be combined with the gearbox of a 200cc engine without causing any problems and even performs better than the large 200cc engine.
From about 1982 onwards, engines of PX125 and PX150 have been fitted with a gearbox almost identical to the one of a PX200. In these cases it’s possible to directly extend the primary drive to transfer the plus of performance to speed.
We recommend using a primary drive wheel with 64 teeth. Depending on the area of use, you can adapt the total gear ratio with a clutch sprocket. The advantage of a primary drive wheel with 64 teeth is, that you may use the BGM clutch sprockets with 22, 23 or 24 teeth.
So you can set your engine for anything between “sporty and short for cities (22/64)” and “highway – provide a maximum (24/64)”.
Our next post will be on various carburetors and intakes on our LML test engine.
https://blog.scooter-center.com/wp-content/uploads/2016/04/development-bgm177-cylinder.jpg5321060Jenny Haashttps://blog.scooter-center.com/wp-content/uploads/2023/08/SC_BLOG-300x69.pngJenny Haas2016-04-01 07:35:522016-04-06 12:22:36BGM PRO 177 cc cylinder for Vespa PX125-150, Sprint150 Veloce – part 2
We would like to present the new BGM177 cylinder, which will be available in April 2016.
First video of BGM177 – 177cc cylinder for Vespa
At Scooterists Meltdown we have shown the cylinder for the first time. The new online scooter magazine SLUK interviewed Philipp and published an exclusive video about our new cylinder:
Fits all Vespa 125 / 150 largeframe engines with 3 transfer ports.
For instance:
Vespa PX125
Vespa PX150
Sprint 150Veloce
Vespa GTR125
Vespa TS125 and
Cosa 125/150.
Powerful and reliable cylinder made of alloy
We have designed a powerful and reliable companion for you.
We have put many ideas into practice to design a cylinder with the highest possible wide range of performance.
BGM177 was made of alloy, just like all modern cylinders.
Very good heat dissipation is one advantage, which is positive for lifespan, consumption and performance.
The cylinder hole is coated with nickel, silicon and carbide and extremely wear resistant. The forged piston is made of alloy and has two piston rings.
Very light piston
The design of the piston paired with a high degree of silicon in the material used, generated a lightweight of 193 grams with high thermal and mechanical stability, which is positive for torque and smooth running.
The piston rings are 1mm thick and are being produced by a renowned Italian manufacturer, which also supplies leading piston manufacturers like Vertex and Meteor. The thin rings minimise friction, which increases performance and make it possible to easily enlarge the outlet duct window.
The gudgeon pin is biconic, which means that its inner ends are thinner than the middle part, further reducing the weight of moved massed.
Alloy cylinder with ceramic coating and large transfer ports
Large ducts and large transfer ports in the cylinder are the best basis for a wide range of performance and an early torque.
The BGM177 can be combined with simple serial components, like the original SI20 carburetor and an original exhaust. This already increases performance significantly. A modern designed cylinder leads to very low consumption at high torque in the low revs range.
Cylinder with vast potential for tuning
Do you want more performance? The BGM177 offers plenty of potential and possibilities to further increase performance with a minimum of work. The cylinder reacts very well to larger carburetors and support by an exhaust like the BGM BigBox Touring.
Transfer ports in the cylinder base can easily be enlarged. The two large transfer ports on the left and on the right are only slightly covered, so that you can easily open them up with a small hand drill. So you can either fit the cylinder to an already adapted engine casing or copy the duct profile to an engine casing.
CNC-milled cylinder head
The CNC-milled cylinder head has many cooling areas and the hole in the centre of the cylinder head prevents air of being stored in the combustion chamber.
It’s also possible to place a temperature sensor in the hole of the cylinder head. This position close to the combustion chamber grants a reliable measurement of temperature.
Placing a temperature sensor below the ignition plug using an adaptor ring or above the thread outside the cooling fin are commonly used methods, but they don’t generate reliable results. In these cases you can only see the temperature of the cooling air close to the ignition plug or the temperature of the cylinder head at the outside of the cooling fin. We think that these positions are simply unsuitable to gain reliable results. BGM therefore prefers a position as close as possible to the combustion chamber.
Combustion chamber for wide performance range
The combustion chamber was designed to grant a wide performance range. A strong expansion exhaust chamber may be used after adapting the squish gap, thanks to the design of the cylinder head insert. With a 57mm engine displacement and a touring or box exhaust you can use the provided gaskets to adjust the squish gap to 1mm.
You are using the cylinder with an expansion chamber exhaust and 60mm engine displacement? We would recommend starting with a squish gap of 1.2mm.
Timings 57mm
With an engine with a stroke of 57mm and a squish gap of 1mm, you will reach the following values:
Compression 10.3:1
Transfer timing 118°
Exhaust timing 171°
Thanks to the dimension of the cylinder you will only need a 4mm gap to centre the cylinder head in the hole. The gap will prevent the cylinder head to stick out into the combustion chamber, even if you adapt the engine displacement. With an engine displacement of 60mm and depending on the engine concept you can lift the cylinder even further to achieve significantly larger transfer port angles.
Timings 60mm
With an engine with a stroke of 60mm and a squish gap of 1mm, you will reach the following values:
Compression 10.8:1
Transfer timing 123°
Exhaust timing 173°
The outlet width is 42mm (66%) and therefore offers positive conditions for an engine with high torque at small trigger delay angles.
BGM177 vs PX 200 12HP
Plug & play with a lot of power
This is a comparison between a BGM177 and a standard Rally200 with 12HP Piaggio cylinder (comparable to a Vespa PX200 GS).
The BGM177 cylinder has not been adapted for this experiment and is used with a Sprint Veloce engine.
Intake, crankshaft and engine ports have not been adapted.
We only attached a SI24 carburetor of the 200cc models without adapting the carburetor box or engine casing and combined it with a BGM BigBox Touring.
Jets are very similar to those of a standard 200cc version:
Main air correction jet: 160
Atomiser: BE3
Main jet: 125
Idle jet: 55/160
Air filter: standard (no additional holes)
Ignition advance was adjusted to 19° before the upper dead centre .
You can clearly see the wide range of performance (straight line) and the high torque (dotted line) at idling even with a non-adjusted engine.
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The next post will be on increasing performance with this cylinder and a LML reed valve engine will serve as basis.
