• Oct 14, 2010
Nembo Motociclette Super 32 Rovescio on the dyno – Click above for high-res image gallery

These days, most of the real innovation in the automobile world seems to stem from an attempt to completely replace the classic internal combustion engine. But that doesn't mean there isn't life left in 'ol Bessy, now does it? Judging by the efforts of Daniele 'Titus' Sabatini of Rome, Italy, there's plenty of new thinking going on.

Called the Nembo Motociclette Super 32 Rovescio, this air-cooled three-cylinder engine uses a single overhead cam and two valves per cylinder. Displacement is said to range from 1850 to 2100cc, and power will be between 160 and 250 horsepower. Nice, but pretty conventional so far. Here's where it gets different: Unlike just about every other inline motorcycle engine currently in production, this engine is upside-down. In other words, the cylinders are positioned below the crankcase.

Why? According to Sabatini, the engine's strongest part – the crankcase itself – can be isolated as the bike's dominant structural frame member. While that's also generally true of more standard designs, Sabatini believes that the arrangement of leaving the finned cylinders at the bottom completely unencumbered by frame tubes or plastic shrouds is more aesthetically pleasing and can lead to a lighter structure.

Do you agree? Check out the photos in our high-res image gallery below and read through the press release after the break. Then, let us know what you think. Us? Well, you can color us intrigued.



[Source: Nembo Motociclette via The Kneeslider]
Show full PR text
Nembo Motociclette: a new brand, a new engine for a new bike designed and built in Italy.

Daniele "Titus" Sabatini, owner, project leader and designer of Nembo Motociclette, presents his new engine, the "Super 32 rovescio" made to equip the naked motorcycles he will build in small series on request for road/track use.

The engine "Super 32 rovescio" contains in the name its main features: three-cylinder 2000 cc (122.05 cubic inches) inverted or if we like," upside down ".

I've chosen this particular engine architecture for both functional and aesthetic reasons. Loving motorcycles as the highest dynamic expression of the fusion between driver and machine, I have a concept of the bike that sees the engine at the first place.

I like air-cooled motors or also water cooled just if with finned cylinders and heads. However, in the current naked sport bikes, often the engine is too much hidden and totally water-cooled, practically soulless. It pains me to see it humiliated and smothered under frames and plastic components. So, I've thought that a good way to get a well exposed and updated air-cooled engine in a contemporary naked sport bike was just to invert it!

As you know, the inverted in line engines are not new: they have equipped many famous combat aircraft especially of World War II, the new thing lies in equipping with them a motorcycle to combine form and function in an interesting way.

I wanted to build a high performance big-bore motorcycle, looking new but also with a classic and timeless beauty built with very few and high quality metal and carbon-fibre components and very light. I was not interested to make a bike with an extreme look, I liked to make a bike that looked like a true motorcycle and not like a manga robot.

Inverting the engine allowed me to achieve these results. I've designed and built a motorcycle, the "SUPER 32", where the engine, by mean of the super compact crankcase, totally placed over the cylinders and the heads, works as a real chassis while the cylinders do not participate in any way in the structural functions.

I decided to add a small trellis in the front and an essential saddle frame, not connected to each other (made in steel, because given the dimensions involved, carbon, aluminum or titanium are practically useless), above all for aesthetic and traditional reasons than for real structural needs, because the connection to the steering column and to the saddle can be obtained directly in the crankcase shape and the carbon-fibre swingarm directly pivots in the crankcase.

So I had to build a naturally aspirated inverted motor first, an Euro 3, with precise technical and aesthetic specifications and I've found an ideal interlocutor in the excellent, and appreciated Chief Engineer Giovanni Mariani.

Giovanni, with his young and skilled design team, composed of the very good engine Chief Designer Fabio Falcone, the talented Design Engineer Alessandro Sobacchi and the capable Engine Designer Marco Fasani, has developed for Nembo Motociclette a very powerful and extremely compact engine, making possible the engine layout I liked to get. Sandro Carò, gentleman mechanic (where the border between mechanic and engineer is so ephemeral), has personally taken care of the engine assembly and his suggestions have been so precious.

The "Super 32 Rovescio" Euro 3 engine can have displacements ranging from 1850 cc to 2100 cc, a power ranging from 160 bhp to 250 bhp, and torque values between 16.5 and 24.5 kgm, without the use of compressors.

The peculiar lay-out of the "Super 32 Rovescio" allows an easy access to any part of the engine makes the heads and the cylinders totally exposed to the air and well visible, with the intake manifolds naturally upward in front of the cylinders and the exhaust manifolds downward behind them.

The result is that the "SUPER 32" bike has an exciting shape, is very light, with a dry weight ranging between 140 kg and 155 Kg depending on the requested outfit, has a profitable weight distribution and can be "short" or "long": in the present configuration has a carbon-fibre swingarm of 670 mm and a 1450 mm wheelbase.

The "SUPER 32" bike is built on request and the first two prototypes will be presented before Christmas 2010.

Nembo inverted 3 cylinder engine on the dyno

SPECIFICATIONS
Dimensions:
Maximum width : 480 mm
Maximum height: 480 mm
Maximum length: 420 mm

Technical data – air/oil cooled prototype engines

Engine : 1814cc inverted - 4 stroke - 3 cylinders – Euro 3
Bore : 100 [mm]
Stroke : 77 [mm]
Displacement : 1814 [cc] - 110.7 cubic inches
Compression ratio : 10.5 : 1
Valvetrain : SOHC (single over head camshaft)
Number of valves : 2 valves per cylinder
Cooling system : air/oil cooled
Lubricating oil system: dry sump
Transmission : 6 speed
Maximum power : 160 [bhp] @ 7000 [rpm]
Maximum torque : 16.5 [kgm] @ 5250 [rpm]
Maximum engine speed : 7500 [rpm]
Weight : 90 [kg]

Engine : 1925cc inverted - 4 stroke - 3 cylinders – Euro 3
Bore : 103 [mm]
Stroke : 77 [mm]
Displacement : 1925 [cc] -117.47 cubic inches
Compression ratio : 11.5 : 1
Valvetrain : SOHC (single over head camshaft)
Number of valves : 2 valves per cylinder
Cooling system : air/oil cooled
Lubricating oil system: dry sump
Transmission : 6 speed
Maximum power : 200 [bhp] @ 7500 [rpm]
Maximum torque : 19 [kgm] @ 5500 [rpm]
Maximum engine speed : 8000 [rpm]
Weight : 85 [kg]

Engine : 2097cc inverted - 4 stroke - 3 cylinders – Euro 3
Bore : 107.5 [mm]
Stroke : 77 [mm]
Displacement : 2097 [cc] - 127.97 cubic inches
Compression ratio : 12.5 : 1
Valvetrain : SOHC (single over head camshaft)
Number of valves : 2 valves per cylinder
Cooling system : air/water cooled
Lubricating oil system: dry sump
Transmission : 6 speed
Maximum power : 250 [bhp] @ 8000 [rpm]
Maximum torque : 24.5 [kgm] @ 6500 [rpm]
Maximum engine speed : 9000 [rpm]
Weight : 85 [kg]


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    • 1 Second Ago
  • 29 Comments
      • 4 Years Ago
      Somehow, I can't imagine an upside-down engine designed in Italy being all that reliable. Maybe they can prove me wrong.
        • 4 Years Ago
        I can't imagine it to be less reliable than other Italian manufactured product.
      • 4 Years Ago
      In the past, some aircraft have used inverted inline engines (like the Fairchild PT-19 trainer of WWII):

      http://wapedia.mobi/en/Fairchild_PT-19
      • 4 Years Ago
      Correction: single UNDERHEAD cam...
      • 4 Years Ago
      Oil flow must be interesting...
        • 4 Years Ago
        I was thinking the same thing. It will be interesting to see how they redesigned the oiling system to handle the inverted layout.

        Most conventionally designed engines (pistons on top) that I have seen turned over and then righted, have had to burn off oil for a while when finally re-fired.
        • 4 Years Ago
        Like radials in aircraft the oil would all seep down into the combustion chamber @ rest. The when you fired it up you would burn off all of that oil and get the big puff or blue smoke, just like all of the radials.
        • 4 Years Ago
        Exactly. How do you stop the oil from pooling on top of the piston rings? Where does it drain?
      • 4 Years Ago
      am i the only one that is thinking "really, air cooled???"
      • 4 Years Ago
      I agree completely with others that having the crankshaft at the top of the motor would raise the center of gravity, however I reserve judgment until after a comparison test ride with my Fz6. You name the track.

      Just please don't call it Motociclette, that would be like calling my bike Yamahoppy.
      • 4 Years Ago
      While I like his out of the box thinking. I see this as raising the CG of the bike pretty high. All the heavy bits are in the crankcase and putting that up high seems counter productive.

      Of course, seeing it mounted in a bike would help.

        • 4 Years Ago
        I believe a high center of gravity on a bicycle creates better tossability and agility, due to the gyroscopic effect, whereas low center of gravity makes for easier, more stable riding. Hence why most sportbikes have the rider perched on top, while cruisers put the rider low in the frame. This design would make for a more agile, twitchy bike, but I could be wrong.
        • 4 Years Ago
        What is the advantage? We can debate all day over whether it helps or hinders a bikes flickability. In the real world, this engine will likely be too expensive to see any of the major manufacturers purchase the rights or design something similar. It offers no power advantage, no improvement in fuel economy, its just as heavy. Why go through the whole process of redesigning an engine to operate upside-down and a motorcycle frame to mount said upside-down engine on for no significant advantage?
        • 4 Years Ago
        Yup, I believe you are right. The only positive thing from Buells besides their looks was the low center of gravity, made it easier to throw around in the twisties.
        • 4 Years Ago
        Raising the CG of the bike increases the rotational moment of inertia about the pivot point on the tire. It would take more effort to toss the bike from side to side. However, the higher CG helps lessen the effort when the bike is leaned over on one side because of the longer lever arm. It becomes less stable the farther it leans over. I don't like it.
        • 4 Years Ago
        @Reuben
        Read it again… that's exactly what he's saying. His design brings the core of the structure - the heaviest component - more to the geometric center. There's a big structural advantage to having the center of gravity close to the geometric center.
        • 4 Years Ago
        high CG can't be good, closer to geo center or not.

        It's like wondering, why not strap on a weight belt when riding to raise your CG?
        • 4 Years Ago
        This puts the hottest part of the engine on the bottom, heating parts that would otherwise be cooler, and breaking down the oil faster. This in addition to a higher C/G. Not so elegant after all.
        • 4 Years Ago
        Agreed,

        Also doesn't it make more sense to redesign the frame in order to use the crankcase as a primary structural member rather than redesign the engine. Seems far more complex this way.

        But I guess I'd have to see it.
      • 4 Years Ago
      I can't argue with any man who says an engine is an aesthetic enhancement, but physically speaking there are other reasons why the heavy stuff is on the bottom. Harley does just fine leaving their engines in the open and having them mounted regularly.
      • 4 Years Ago
      I would have to see it mounted on a motorcycle to see if it really is aesthetically pleasing, but as I see it in the gallery, it is not. Maybe it is that I'm just used to the conventionally mounted engines?
        • 4 Years Ago
        I'd agree with that... Of course, if it's mounted behind plastic, you wouldn't really see much anyway.

        • 4 Years Ago
        It would just make me worried a lot more about bottoming out, etc. I'd rather hit the crank case than the cylinder head.
      • 4 Years Ago
      Don't forget that this design necessitates a dry sump system and I for one would like to know how the oil is segregated from the bottom dished portion (now top side) of the pistons. This is likely some interesting engineering but sure does not help the cost curve.
      • 4 Years Ago
      "overhead" Cam. If it's upside down wouldn't that make it an "underhead" Cam?
      • 4 Years Ago
      As the age of the air cooled motorcycle draws to a close, you have to wonder where the radiator is going to go......
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