Vespa ignition retrofit electronic ignition

Vespa Largeframe Conversion to electronic ignition

Vespa engines of the LargeframeModels with rotary valve inlet control, e.g. Vespa VNA, VNB, VBA, VBB, VLA, GT, GTR, Sprint, Rally, PX, LML 2T, Bajaj Chetak can now be easily converted:

Why should I convert a Vespa to electronic ignition?

These are the advantages of an electronic ignition!

After the retrofit, the former weak 6Volt on-board network is available powerful 12 volt light output. The previously self-regulating electrical system is switched to a reliable and bulb-friendly controller control (e.g. with BGM6690) changed. The high-quality cabling ensures that the high light and ignition power With its high wattage, it already provides one when idling very good light outputwhich does not break down even when using the indicators or additional power consumers. No maintenance required! Maintenance work, as is usual with contact ignitions, is not necessary.

Our new bgm ignition: specially developed for converting contact-controlled motors to a maintenance-free electronic ignition:

The latest version of the proven bgm PRO HP (High Power) ignition base plate for converting from contact ignition to electronic ignition.
Suitable for e.g. Vespa Largeframe such as: VNA, VNB, VBA, VBB, GL, Super, Sprint, GT, GTR, TS, Rally

Buy ignition here now

bgm PRO ignition base plate

We have our own brand bgm, tried and tested a thousand times bgm PRO ignition base plate revised and even better did. Particular attention was paid to the very high quality of the bobbins and the pickup.
In addition, the cabling was converted to textile-sheathed silicone lines. A special gimmick is the cord already attached to the cable branch for easy pulling of the cable harness through the cable duct in the motor housing. The base plate now also has a degree of precise scaling for easier setting.

Compared to a conventional electronic ignition, the BGM Pro HP V2.5 ignition base plate has specially combined coil windings.
This significantly improves the efficiency of the alternator and offers a high light output of 120W.

In contrast to a Vespa PX ignition base plate, the BGM Pro HP has one longer and differently laid cable branch so that the ignition base plate can also be perfectly mounted on older vehicles. In addition, it has an adapted base plate contour so that it fits perfectly on engines before 1977 (with a larger shaft seal seat than PX).

  • High light output (120W) thanks to the maximum number of windings
  • Proven excitation coil with copper plate for maximum reliability
  • Pickup with a carbon barrier layer for a clean ignition pulse
  • Neatly processed light coils
  • High quality solder joints
  • Original cable lugs and length for easy cabling
  • Can be combined with additional modules (PiFi, Kytronic, Agusto)

NOTE: The BGM Pickup has a nominal resistance of 100 Ohm (+/- 10Ohm)

Silicone lines


  • Extremely temperature resistant (-40 ° C to + 250 ° C)
  • Always stay flexible
  • Very good mechanical protection through the textile fabric
  • Resistant to fats, oils, alcohols, oxygen, ozone
  • Very high insulating properties


When converting from a contact ignition to this base plate, another fan wheel, a voltage regulator and a CDI must be used.
A possibly standard old voltage regulator, like the series ignition coil, is no longer required.
With the BGM voltage regulator BGM6690, a battery (12 volt battery required) can optionally be charged while driving. The old wiring harness can still be used, but the previously individual circuits must be combined here, as the voltage regulator only offers one outlet to the complete power supply. It is easier to convert to one of our conversion wiring harnesses (e.g. 9077011).

Everything necessary for this is available individually or as a set.

Suitable for Vespa oldieLargeframe

The BGM ignition stator fits all Vespa engines of the Largeframemodels with rotary valve inlet control, e.g. Vespa VNA, VNB, VBA, VBB, VLA, GT, GTR, Sprint, Rally, PX, LML 2T, Bajaj Chetak.

Buy ignition here now

Conversion set

In addition to the ignition, you also need a few other parts to convert the engine from contact ignition to electronic ignition. We have put together a practical set for you: BGM6661PRO

All parts are also available individually:


The alignment of the crankshaft in the engine housing, and thus also the position of the pole wheel, is the same as the old one Largeframe Engines (recognizable by the same-sized crankshaft bearings with 25x62x12mm) are significantly more variable than, for example, the later PX engines.

The crankshaft bearings are not fixed in the engine housing by a circlip, but simply sit with a slight interference fit in the housing. Various tolerances (e.g. the width of the shaft sealing rings, worn bearing seats, orientation of the cone on the crankshaft) can lead to significant deviations from the originally intended positioning of the shaft in the crankcase. A prerequisite for a correctly working ignition is that the pole wheel is perfectly aligned with the ignition base plate. Otherwise the trigger surface in the pole wheel will not run parallel to the pick-up, which can lead to misfiring. If the ignition does not produce a spark, the fault is usually to be found here. For easy rectification, we offer spacer plates (BGM8000S05) for the pickup on the ignition base plate. This allows the correct distance to be restored in a simple manner.


The bgm PRO conversion ignition fits the following models:

Vespa PX80 conversion tuning

Easily convert the Vespa PX80 to 125ccm - this is how it works:

The vehicle prices for the Vespa PX models have been rising for years. The cheapest models are still the Vespa PX 80 / PX80 Lusso. The 80s Vespas have the least performance and are rated the most expensive by insurance companies. When converting to 135ccm or 139ccm, the scooter can no longer be driven with the 125cc driver's license. Here we show you how you can easily convert a PX80 to a PX125 without having to work on the crankshaft or the gearbox:

Cylinder -SCOOTER CENTER Conversion cylinder Vespa PX80 to 125 cc- Vespa PX80 / PX80 Elestart

TÜV registration possible! TIP: Suitable for Elestart engines without modifications!

Advantages of retrofitting:

  • more performance and safety reserves in road traffic
  • less consumption approx. 20% according to customer experience
  • Can be driven with an old 125 driver's license
  • cheaper insurance
  • same durability
  • easy installation

We offer you a complete cylinder kit to bring every PX80 plug & play to 125ccm displacement.
If the kit is registered with the TÜV as an individual approval, you can use the significantly lower insurance rates of the 125cc models benefit. All you have to do is change the cylinder, including the piston and head, the short motor remains unopened!

More performance - less consumption

Originally the 80ccm engine has about 5HP on the rear wheel. With our conversion cylinder, the performance increases by a whopping 60% to a remarkable 8PS and that with extreme reliability. This means that the performance of the cylinder is already in the range of a 135 DR. In this diagram you can see a direct comparison between a 135 DR tuning cylinder (blue curve) and the SCK 125cc conversion cylinder (red curve). In connection with an extended transmission (possible by simply changing the clutch pinion to 22 teeth), the top speed is also significantly increased. The significantly wider torque curve means that the gears no longer have to be fully accelerated, and consumption is reduced.


Performance Graph 125cc Conversion Kit vs DR135

Performance Graph 125cc Conversion Kit vs DR135

Are the brakes and frame overloaded?

No, with the conversion kit you are on the safe side - the Vespa PX80 has the identical brake and chassis components like a Vespa PX125 and even a Vespa PX200, which is / was available from the factory with 12PS.

Durability of the cylinder

The durability is at least as good as the original cylinder: almost indestructible. Two, with prototypes of the Scooter Center In 2011, vehicles equipped with conversion cylinders were on the road for several thousand kilometers without problems or breakdowns. The drivers are from the Performance and low consumption simply enthusiastic.

5 star rating of Bernd:

"installation was easy, it only took 1 hour has run for about 300 km without problems with a 105 hd now drive in 3rd gear with half throttle where I used to have to take 2nd gear with full throttle fuel consumption has decreased by about 20% this cylinder set was the best investment in my vesp so far"
Complete cylinder kit to bring every PX80 plug & play to 125ccm displacement. If the kit is registered with the TÜV as an individual approval, you can benefit from the significantly lower insurance rates of the 125cc models. All you have to do is change the cylinder, including the piston and head, the short motor remains unopened!

Rating in Scooter Center Online-Shop

Recommended motor settings:



Video about the Vespa PX80 - PX125 conversion cylinder


TÜV certificate and Piaggio approval

Unfortunately, it is currently not possible to deliver this cylinder with a TÜV certificate.
The technical and formal hurdles for such an expert opinion are now so high that it is not economically feasible (the selling price of the cylinder would then be much too high).

The Vespa PX80 has the same brake and chassis components as a Vespa PX125 and even a Vespa PX200!
It is therefore possible to have one official approval from Piaggio you can get it Request online HERE. This is made specific to the chassis number, so a mere copy is not enough.
The TÜV then has the working document in black and white that the PX80 also has the same brake and chassis components as a PX125 (or even PX200). Equipped with this, the engine that has been converted with our cylinder can then be demonstrated. The official Piaggio document usually opens doors and gates.


Possible tuning measures

"Stage 1"
If you want to elicit more power from the cylinder, you can turn the cylinder by approx. 1mm on the head sealing surface.
The crush dimension (distance piston to cylinder head) should then be approx. 1,1mm at the narrowest point. Simply push 2mm solder through the spark plug hole into the edge area of ​​the combustion chamber and turn the crankshaft.

"Stage 2"
If you want significantly more power and torque, you can easily achieve this with the original cylinder head of the PX80. Due to the smaller combustion chamber, the compression increases again significantly and the power / torque increases by at least 1PS / 1NM. For this, however, the distance between the cylinder head and piston should also be checked (at least 0,8mm) to avoid mechanical damage. The sealing surface of the cylinder head protrudes into the combustion chamber of the cylinder. This is only an optical shortcoming, technically this solution is completely unproblematic. .

"Stage 3"
Furthermore, the outlet window can be widened 1mm on each side. With these measures, the cylinder is already scratching the 10PS brand. With a lighter fan wheel we already have over 11PS and 13Nm is reached (see second diagram). The driving behavior is therefore very similar to an original Vespa T5. Individual adjustments to the jets and the ignition setting are then of course mandatory.


Vespa PX80 conversion tuning


This week there is the final report on our conversion cylinder for the PX80. With this complete kit, each PX80 can easily be brought up to 125 cc displacement and benefit from the significantly lower insurance rates associated with it. All you have to do is change the cylinder including the piston and head, the short motor remains unopened!

Originally the 80ccm engine has about 5HP on the rear wheel.
The SCK conversion cylinder increases the performance by a whopping 60% to a remarkable 8PS, all with extreme reliability.

We are already above the level of a DR135, despite 10cc less displacement!
The diagram shows the direct comparison between the DR135 (red curve) and the new 125cc conversion cylinder.
In conjunction with a longer gear ratio (possible by simply replacing the clutch pinion), the top speed is also greatly improved.

Another big plus point is the significantly cheaper insurance due to 125 cc displacement instead of 80 cc.
In addition, with a vehicle that has been converted to 125cm, you are not only more confident and cheaper on the road, the consumption is also usually cheaper because the significantly higher torque means that you no longer have to constantly drive at full throttle in order not to represent a traffic obstacle.
Something that may only become apparent at second glance is the significantly improved resale value of the vehicle. Holders of a car driver's license, if it was issued before April 01.04.1980st, 125, are able to drive motorized two-wheelers up to XNUMXccm without having to pass an extra test.
As a result, the market value of the 80cc vehicles specially designed for the German market was reduced substantially overnight. Anyone who has the appropriate driving license will use a more powerful 125cc vehicle than a weaker 80cc drive.
The conversion will make the vehicle much more attractive for a possible sale.
All in all, the cylinder purchase pays for itself quite quickly.

Two vehicles equipped with the conversion cylinder were on the road for several thousand kilometers without problems or breakdowns in 2011. The drivers are very satisfied with the performance and the low consumption.
We will test a few more optimizations during the week, especially with regard to performance, and then give our GO.

Here is a direct comparison between an original PX80 with SITO Plus sports exhaust (blue curve) and our 125cc conversion cylinder with original exhaust (red curve):

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