The perfect Vespa touring engine

Creado por Jesco a las 17:12 el 20 de diciembre de 2021

Which touring engine is perfect for a Vespa? We at SIP Scootershop get this question again and again. Timo from the "Blechgefährten" has also been on the topic for a very long time, as he is looking for the perfect setup for his PX conversion. A setup that is suitable for everyday use as well as for long tours and mountain passes. Jesco didn't miss the opportunity to invite the YouTuber from faraway Wolfenbüttel (Jesco's hometown) to our flagship store in Landsberg to put together the numerous parts and details for a perfect touring setup.

Cylinder QUATTRINI - Vespa Touring Engine | QUATTRINI M-244 Setup

For more than a year Vespa fan Timo had been working on his PX conversion project, but now it was time for the engine tuning. The basis: A QUATTRINI M-244 - probably the best current all-round cylinder for a Vespa PX 200 engine. The QUATTRINI M-244 convinces both by its everyday suitability in city traffic and on longer tours by reliability, smoothness and as a racing engine with torque strength and rich power. The QUATTRINI M-244 cylinder for 57 mm or 60 mm stroke has, as the name suggests, a cylinder with 244 cc displacement and is suitable for all large 200cc engines such as Vespa PX200, Vespa Rally200 and Vespa Cosa200 with Ducati ignition.

The Quattrini cylinder has the following special features: First, it does not have a cylinder base that protrudes into the engine case. The absence of the cylinder base means that a significantly larger piston with a very low compression height can be used. The compression height is the distance between the piston crown and the axis of the piston pin. In addition, the Quattrini cylinder requires a crankshaft with a very long connecting rod. Because the compression height is very low and at the same time the connecting rod is very long, a reliable cylinder with low piston tilt was feasible without a foot. This way, the transfer ports are located so far up that no more adjustment in the engine casings is necessary - although adjustment with files and milling is always advisable.

In addition, the cylinder has a design with a 72 mm bore due to the lack of a foot. This means that the aluminum racing cylinder with Nikasil coating can be virtually "plug & play". This was another criterion for Timo, who was looking for effortless implementation and assembly. So just "find the right components, put them on - and then you are ready to ride," says the guy from Wolfenbüttel.

By the way: Since 2020, the new versions of the Quattrini M-244 cylinders have a small bore above the exhaust port, also called a "decompression bore. This is intended to make the engine easier to "kick-start" - i.e., start - and to run more smoothly at idle speed, especially in large-volume single-cylinder engines. The bore no longer has any influence on engine running and power delivery at higher engine speeds from around 1,500 to 1,800 rpm, as the cross-section of the hole is too small to allow a significant throttle change in a short time.

Another interesting detail of the Quattrini M-244 cylinder is that due to the lack of a base, the cylinder centers itself on the case using studs, which is why they are positioned relatively close together. On rare occasions, there are certain engine cases where, given the tolerances, one of the stud holes needs to be enlarged. This makes up for the tolerance of the housing, while the other studs center the cylinder. Even though the ordinary stud bolts can be used for this purpose, it is recommended to use stud bolts from the automatic range, which are provided with so-called expansion bolts. This is to counteract the deformation of the cylinder that can occur when heated.

Crankshaft/Long Stroke Shaft - Vespa Touring Engine | QUATTRINI M-244 Setup

The crankshaft and the cylinder are the heart of every engine, but also one of the most stressed. Vespa expert Jesco has therefore selected a 60 mm crankshaft for the YouTuber called “Blechgefährten”, which fits perfectly to his setup and "plug & play" into the original casings, is particularly smooth running and has high-quality materials and first-class workmanship. Another advantage is that with the crankshaft all PX clutches can be ridden as standard. In addition, there is now also an increased displacement from 232 cc to 244 cc.

Small tip: It is advisable to decide in advance whether the crankshaft should have an ordinary rotary valve intake or rather be converted to a reed valve intake. In order not to be too loud and reliable in everyday life, expert Jesco has recommended a rotary valve intake in this case.

SIP also has something brand new in its range: the SIP PERFORMANCE crankshaft/long-stroke shaft with splines on the clutch side, which normally has a tapered cone with a key. This serration system, originally from the BFA engines, has now been adapted to the SIP PERFORMANCE long-stroke shaft and developed for different clutch systems.

Clutch - Vespa Touring Engine | QUATTRINI M-244 Setup

The perfect connection to the crankshaft is provided by the SIP COSA 2 Ultrastrong clutch. This is now also optionally available with the gearing from the BFA engines.

Small tip: For all those who prefer to look for a crankshaft with individual gearing setup instead of a whole new clutch, the clutch base plate MMW for clutch basket "Superstrong" "COSA 2" can of course also be ordered separately. This makes it easy to switch to the serration system.

Oil Seal / Oil Seal to seal the crankshaft - Vespa Touring Engine | QUATTRINI M-244 Setup

The inner oil seal is often considered the weak point of Vespa Largeframe models with far-reaching consequences. Because in case of a defect of the inner seal ring the whole engine must be disassembled. In the past, there were solid rubber rings in the colors brown, black and blue. These were followed by metal rings with only a middle rubber part. Over the years, manufacturers such as Rolf with their "brown Rolf" and Corteco established themselves for sealing the crankshaft.

In the meantime, fortunately, the high-quality sealing rings Oil Seal Crankshaft CLUTCH MALOSSI FKM 31x62x5,8 mm and the Oil Seal Crankshaft CLUTCH PIAGGIO 31x62x4,3x5,8 mm provide relief. Both offer a secure sealing of the crankshaft as well as snug fit for all Vespa Largeframe engines, therefore, if adjusted properly, promising proper riding pleasure for many years and kilometers.

Carburetor and carburetor pan cover with separate lubrication - Vespa Touring Engine | QUATTRINI M-244 Setup

For an everyday touring as well as mountain friendly setup it is recommended to stay with the SI carburetor. Expert Jesco has chosen the carburetor PINASCO SI 26.26 VRX-R for Timo from the “Blechgefährten”. This has a CNC machined intake funnel and an optimized float needle valve with extended flow bore. So, the SI typical supply problems of the gasoline in tuned engines should be a thing of the past.

Another plus point is the included accessories such as intake funnel and foam air filter, which do not have to be purchased additionally. Small downside of the funnel: disadvantage of the design is the somewhat more difficult tuning of the carburetor or simply "give the carburetor a little more love when tuning", as Vespa expert Jesco calls it. However, the carburetor can also be installed without the funnel. This costs a little power but is quieter and somewhat easier to tune.

But even the best carburetor can't perform to its full potential if it doesn't have the ability to draw in enough air. For this purpose, the carburetor pan covers from PINASCO were developed. Thanks to their significantly larger volume, the engine can draw in air a little more easily. With this setup, this results in about one horsepower more, which is available over the entire power band. A practical gimmick is also the associated rubber pin, which is included in the scope of delivery. It provides additional safety, as this prevents the idle throttle screw from loosening and thus falling into the carburetor, which would cause the destruction of the rotary valve.

Ignition SIP PERFORMANCE by VAPE Road - Vespa Touring Engine | QUATTRINI M-244 Setup

One of the most successful products from SIP is the ignition SIP PERFORMANCE by VAPE. It provides a powerful power supply, a strong, reliable ignition spark and has a particularly stable flywheel.

Many tuning ignitions have the problem that the current output is lower. "If you then stand at the traffic lights or at the level crossing at night, the light always goes dark and just glows," says Vespa expert Jesco. With the SIP PERFORMANCE by VAPE Road ignition, which is available in DC and AC variants, this is not the case. Here, eight light coils on the base plate generate sufficient electrical power even at idle speed. At higher speeds, this increases up to 110 W. Furthermore, the connection of additional, digital elements or connection of LED lighting (with additional battery) is possible thanks to the integrated rectifier.

The ignition SIP PERFORMANCE by VAPE is available in two versions: as a road version with static ignition timing or flat ignition curve like the original and in the sport version with variable ignition timing and similar ignition curve to the IDM ignitions of other manufacturers such as Vespatronic, Malossi and Polini.

The extremely stable flywheel, which is made of one piece, also has some advantages. Usually, the cone is connected to a flywheel wheel via rivets, but these form a weak point. Since the flywheel wheel is made of one piece and CNC, engine vibrations as well as wear are minimized.

Racing exhaust SIP ROAD 3.0 - Vespa Touring Engine | QUATTRINI M-244 Setup

The latest exhaust system from SIP is the racing exhaust SIP ROAD 3.0, which offers several advantages. One of them is the dimensions, which are exactly the same as the original and thus come along unobtrusively in typical compact size and appearance. In addition, it grants full vehicle tilt clearance, fits with all stands, and can also be mounted on oldies like a Vespa Sprint or a Vespa VBB. So, a small box that combines well with a wide variety of setups "Plug & Play" with original carburetor and can be ridden comfortably - even with a Quattrini or Pinasco racing cylinder as well as a SI carburetor. Thus, ideal for the city and the everyday cruiser.

Of course, the performance is also particularly noteworthy. "There are even more powerful box exhausts, but then they are bigger, louder and more rev-heavy. And then there is this segment of box exhausts, which are more suitable for everyday use. And in this segment, the SIP Road 3.0 is one of the strongest exhausts together with Polini and Malossi. However, the racing exhaust SIP ROAD 3.0 is the only one that is based on an original box and combines torque with power and a pleasant volume," says SIP Vespa expert Jesco. Thus, thanks to the increase in power, which is largely generated by the shape of the manifold, two to four horsepower more can be expected compared to an original exhaust.

Racing exhaust POLINI or racing exhaust SIP ROAD 3.0?

This is exactly the question that Timo from “Blechgefährten” also asked in the video. According to Vespa expert Jesco: "Depending on the setup, it varies a bit, which one is stronger. But basically, they are really on the same level here". Although the Polini racing exhaust may be equally strong, the product from SIP offers the same power with the same volume as that of the original. Another advantage is the possible installation on older models such as a Vespa Sprint, since the manifolds were also designed to fit this.

Small tip: A test of the different box exhaust systems can be found here:

The gearbox of the Vespa Touring engine | QUATTRINI M-244 Setup

The primary ratio, which is part of the gearbox, determines the length of all gears. If you want to install a high-torque engine - such as a Quattrini with 62 mm stroke - it is worthwhile to extend the gear ratio.

In addition to the auxiliary shaft gear set Z 12-13-17-21 "Standard" DRT 804 for SIP with original gradation, there are also gear sets with narrower gradation, e.g., the auxiliary shaft gear set Z 12-13-17-20 BENELLI, where the fourth gear is one tooth shorter. Although gear sets are also available in which the third as well as the fourth gear - or even the fourth gear is two teeth shorter - this leads to the fact that the gear connections are better, but also the gear spread is much narrower.

In short, the installation of these gears allows the transmission to be further adapted to the needs of the rider and the intended use of the engine. Thus, depending on the engine power and desire, it is necessary to achieve the ideal compromise between starting behavior or gear ratio and top speed.

It is important to note that cush drive abilities reach their limits, especially with tuned engines. This can mean that vehicle jolting is not adequately absorbed, and the springs break as a result. Transmission damage is very likely to be the result. It is therefore advisable to insert springs in the cush drive that offer more resistance.

Small tip: In the meantime, there are also countershafts that can be screwed together. This is super practical easy to install and includes high quality cush drives.

The positioning of the gearshift cross on the drive shaft is considered, in addition to the not quite optimal locking, as a weak point in the Vespa Largeframe engines. The remedy here is a gear selector box MOTORINO DIAVOLO sequential or the drive shaft CRIMAZ with integrated detent. This guarantees a better positioning of the cruciform in the gears, thus preventing possible consequential damage such as transmission impairments or cracked engine casings.

Attention should also be paid to the quality of the cruciform. This is used for every gear change and is therefore one of the parts with the greatest load in a Vespa engine. Therefore, it should have the right hardness. It should not be too hard, so that it does not destroy the flanks of the gears. On the other hand, it should not be too soft either, so that it does not wear out too quickly. Since the shifting crosses from PIAGGIO now have a fluctuating quality, the SIP BFA cruciform is recommended here, for example. It was developed by the Italian high-tech forge BFA for SIP and has achieved excellent results in tests.

You would like to see everything in picture and sound with further detailed and interesting information? Then just take a look at the associated video. Jesco and Timo discuss all the relevant components of the engine setup, from the cylinder to the oil seal and transmission to the exhaust.

By the way: For the subscriber only video, we shot a video with Timo with a look behind the scenes of SIP. So if you've always wanted to know what it's like at our company and how and where our hard-working employees work, you'll find it on Timo's "Blechgefährten" YouTube channel.

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Jesco is a technician and product developer at SIP Scootershop. Many people know him from videos on the SIP TV Tutorial Channel, where Jesco explains complicated stuff in a simple way.