Nembo Motociclette Inverted 3 Cylinder Super 32 Rovescio Motorcycle Engine

Nembo Motociclette inverted 3 cylinder motorcycle engine

Nembo Motociclette inverted 3 cylinder motorcycle engine

A lot of interesting projects come across our desk here at The Kneeslider, but this one, sent in by Daniele 'Titus' Sabatini of Rome, Italy, deserves a bit more attention. It's a brand new 3 cylinder motorcycle engine called the Nembo Motociclette Super 32 Rovescio, a 2 valve, air/oil cooled, single overhead cam, inverted triple. "Inverted," means just what it says, the engine is designed to run upside down. The compact crankcase is used as a stressed part of the chassis without any load being placed on the cylinders and the inverted arrangement get the cylinders well out into the airflow. A dry sump oil system keeps the oil going everywhere it should.

Nembo Motociclette inverted 3 cylinder motorcycle engine

Nembo Motociclette inverted 3 cylinder motorcycle engine

Displacement ranges from 1814cc - 110.7 cubic inches to 2097cc - 127.97 cubic inches with horsepower from 160 to 250 respectively and 119.3 to 177.2 foot pounds of torque.

Daniele is not a fan of the plastic covered sport bikes we see everywhere so he decided his motorcycles would be a visual feast, a good looking engine, a minimal frame and no fairings to hide all of the fins and castings. I like the way he thinks.

This is one project I'll be very interested in following.

Inverted 3 cylinder engine from below

Inverted 3 cylinder engine from below

Press release and more photos below:

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.

Nembo inverted triple showing minimal frame structure

Nembo inverted triple showing minimal frame structure

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.

Nembo Motociclette Super 32 inverted 3 cylinder engine

Nembo Motociclette Super 32 inverted 3 cylinder engine

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

Nembo inverted 3 cylinder engine on the dyno

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]

Nembo inverted triple showing hand for relative size

Nembo inverted triple showing hand for relative size

UPDATE: Kim Scholer writes in with photos of this 1939 600cc MGC upside down 4 cylinder engine from France. The power went through the underhead camshaft to the gearbox, and the aluminum upper frame member did double duty as a gas tank. It was tested with a sidecar for exactly 666 kilometers. Development ended with the German invasion. Thanks, Kim!

1939 MGC inverted 600cc 4 cylinder

1939 MGC inverted 600cc 4 cylinder


  1. Will13 says

    Pretty cool! Daniele is right in that this format was used throughout the aviation industry in the first half of the last century. It will be interesting to see a bike equipped with this engine, and even more interesting to hear it run.

  2. BoilerUp! says

    I like the long intake tubes that this arrangement allows for, should produce high intake velocity. I am interested to see the prototype bike, the output sprocket seems rather high, I wonder if it just looks this way on the bench. Great looking motor!

  3. kneeslider says

    Racetrack Style, corrected. Thanks!

    I have no idea where I came up with my original numbers, must have divided by furlongs or something. Sheesh! 😐

  4. Sportster Mike says

    Wow indeed – great looking engine
    and hopefully won’t stall when riding through puddles!
    seriously though – why don’t these innovative ideas get picked by the big guys?
    Ford Mo Co etc et all

  5. Wol says

    I love it when something just comes out of the blue and bites you. A cracking idea to invert the engine. I always thought that the crankcase and the crank would weigh more that the other end of the engine but now I am wondering if that is actually true and or by how much.

  6. todd says

    I think it will require very short exhaust pipes. If you’re aiming for torque it would be nice to have long pipes to go with that long intake.

    With the mass of the heaviest bits up closer to the weight of the rider the bike should have even better mass centralization than the current convention.


  7. JR says

    AHH nice! I want to see this succeed. I ride an 80 Yamaha XS850 and LOVE the triple howl.

    Best idea since the little Vento 400cc air-cooled triple. I still want to get my hands on one of those little ATV triples Vento makes and make a sweet little cafe racer.

    I can’t wait to see more details about the final look of this bike.

  8. Simon says

    Very unusual, visually not really convincing imo. I wonder if there are any real benefits in this config.

    Also, take a look at the gearbox: the front sprocket will be located way above the wheel axis. So, I guess the pivot axis of the rear swingarm will have to move up as well to avoid chain suck. This will cause a relatively high variation in chain tension, and possibly the need for a chain tensioner of some kind.

    I do respect their guts though, pulling this off in the current economic climate.


  9. says

    hmm… cylinders, heads and the manifold look like Porsche parts, don’t they?

    aside from cooling or looks, another aspect (and i think the most important) of a concept like this is the location of the crankshaft center, as this setup will be likely to provide very low resistance to movements in the roll axis.(Compared to the same crankshaft in a “normal” location)

    same effect than the husaberg enduros show, so the bike will handle very well for a bike with this big displacement.

    best wishes from my side for your project!!

  10. B50 Jim says

    So wacky it has to work! Only from Italy, where they’re not afraid to try anything. Seriously, this engine should provide some great chassis dynamics while eliminating most of the chassis. I like that it leaves the cylinders unstressed; that would have to improve things inside the engine — amazing how far a stressed engine can move and warp under operating loads. Great power delivery — note in the picture the engine is attached to a dyno so they’re confident it can deliver the goods. I’d love to hear this one at full song, having been a fan of inline 3’s since I first heard a Triumph X-75 Trident (among the best-sounding motorcycle engines of all time). As for the countershaft sprocket placement, no problem; just use a tensioner a la Buell.

  11. Sick Cylinder says

    Great, but personally I would be more interested if the displacement was smaller – the older I get, the faster I was and the slower I actually am!

    Also a motor around 750cc would be nice and flickable and it would be easier to ride hard to get the full benefit of the engine sounds – three cylinders (and sixes) allways sound wonderful. .

    What about reversing the engine to have the exhausts at the front – better cooling that way.

  12. Thom says

    @ Sick cylinder- This has been discussed before. It may seem counterintuitive, but it is more beneficial to cool the intakes first, rather than the exhausts, for more power. If you look at the original Chevrolet LT1 350(from 1969!), they had “reverse cooling” on their cylinder heads for this reason.

  13. baconpocket says

    @sick cylinder
    as i understand it, you want your intake as cool as possible, your exhaust to be relatively hot to evacuate gases faster, and your cylinder heads to be within a heat range that is hot enough for efficient power production, but not too hot that you melt the components

  14. Brian Sheridan says

    What makes everyone think this is an inverted engine? Yes, there is a scavenge line on the cam box, or breather line. If it’s inverted, then by my measurements the head is dragging the ground. A counter shaft sprocket is at approximately swing arm centerline, right, then take a close look at the photo’s. You can make just about any engine work upside down, but what is the point? The intake is in the exact spot that many Japanese manufacturers place their intakes on normal right side up engines. It just has a rear facing exhaust. Are you sure we are not all being duped?

  15. FREEMAN says

    @ Brian Sheridan: go ahead and read through the entire article again and the press release. The owner has his reasons for inverting the engine.

  16. BoxerFanatic says

    -If you were above him, then how could you see him?
    -I was INVERTED.
    -Naw, man he was inverted, it was a great move.

    -What were you doing there?
    -foreign relations.

    On topic…
    It looks like this engine could be used in a different orientation than it would be mounted in these pictures, as Brian Sheridan mentions.

    It looks like this engine might be capable of being mounted with the cylinders pointing forward, and somewhat down-angle from horizontal, with the crankshaft stacked above the gearbox. With the intake tract on the top of the engine, and the exhaust underneath.

    I guess I don’t quite understand the advantage of having the crankshaft spinning mass high at the top of the engine, and the cylinder head, intake, and exhaust outlets at the bottom. Just because it CAN, doesn’t necessarily mean that it should.

    Good luck doing valve adjustments from underneath. I guess me, personally, I like horizontal engines, especially the opposed ones.

  17. says

    Very unusual.
    One thing I notice right off the bat is that the intake tract is far from optimal.
    The intake air must travel in a virtually 180-degree turn as it moves from the inlet into the cylinder. This is a serious drawback for breathing, from a performance perspective in a normally-aspirated engine.
    It reminds me of a side-valve intake tract.

    I give it high marks for “unique-ness”, but I can’t get past the intake design enough to take it seriously.

  18. todd says

    well, this IS an air-cooled motor. The last I’ve read about air-cooled inline-triples is that the center cylinder has a tendency to get really hot. Now lets consider how the hottest side of the motor (exhaust) is facing the rear. The rear of the cylinders and head is going to expand an awful lot faster than the front side… Maybe not, I’m just saying.


  19. Scotduke says

    Curious – a lot of successful aero engines were inverted, most notably the Gipsy Major series with fours and sixes and even a v12, as well as the Blackburn and Walter Minor engines. I’d not heard of that French motorcycle before. But with a single cam, two valves/cylinder and that capacity, I bet it’ll be very toquey, a power unit to contend with Triumph’s Rocket III perhaps.

  20. kneeslider says

    Brian, you got me looking closer. I think the inverted arrangement looks so different that it’s easy to be skeptical, but there’s no reason this can’t be exactly what it is represented to be. Your reference to the counter shaft sprocket is the basis of your doubt, but how drive is transmitted to the rear wheel isn’t shown so we’ll reserve judgment. As the photo of the MGC I added above shows, inverted engines in motorcycles have been tried before and there are a lot of aircraft engines with the cylinders on the bottom and they look pretty cool, an attribute this engine might have if installed in a bike. What defines “right” side up? Our expectations? Will this work? We’ll have to wait and see.

  21. Carlo says

    Never seen an engine like that,,, and to think that it was made in my hometown and I never heard of Nembo. Will have to look for future developments, but surely something interesting. BTW, I like this even more for the date! 2763 AVC “Ab Urbe Condita”: since the founding of Roma! 😀

  22. David says

    An inverted engine could become a problem when oil or raw gas find a way to accumilate in the combustion chamber during storage time. My experience with a sticking caburetor float-valve and also with a sticking dry sump, oil \check valve\ on my BSA’s and Triumphs, proved that fluids do some times drain to the wrong place at the wrong time. Even bad piston rings and valve seals can leak residual oil. There also can develop an accumilation of water from condensation.
    Keeping the cylinder heads clean, will be a problem, because of; water-slime, mud, weeds and road debris (tar, paint, sand, small stones etc.)!

  23. OMMAG says

    No cannot .exists that cannot be managed ….. armchair engineers aside …. this concept shows fresh thinking and real ability.

    KUDOS to Mr. Sabatini and his team !
    I’m sure the a-c-c-u-m-u-l-a-t-e-d talent there will have sufficient ability to solve the fluid leakdown issue.
    If it eveb is an issue in a dry sump engine.

  24. chris sidah says

    The reason some aircraft engines were installed with the cylinders down was to gain clearance for large diameter props and still allow for forward visability. There’s no performance or reliability benefit. This looks like a “just because you can” design which is fun but the wheel doesn’t need to be re-invented.

  25. baconpocket says

    i believe the intended benefit is the ability to use the engine as a stressed member without the stress on the cylinder heads. This would be arguably be more stable and more reliable than the same engine with the “correct” side up. Performance-wise, this should allow for less weight of external framework as seen in the above frame design.
    anybody care to chime in with the weight of a typical bike supporting a 2.0L engine?

  26. Brian Sheridan says

    So I’m driving home from Kohler Engines tonight, 34 miles, with nothing to think about except to watch out for deer, and it occurs to me, the cylinder & exhaust were facing backwards, out of the air stream. Yes it can be done, hopefully with water cooling or forced fan cooling, just like a boxer from the Germans. A Harley rear cylinder is partially cooled by the oil from the dry sump crankcase, and they are low output. Why would you start out with that problem with a brand new design, wait, I forgot, it’s upside down, nevermind.
    Paul, on the positive side, it’s neat to see unusual designs, but can you imagine anybody investing any money in this engine, really? I’m having a hard time understanding “why”.

  27. Steve says

    There’s a reason inverted engines never remained popular. Too much friction from the oil at high RPM’s and too mant oil control problems. Never mind that cooling the exhaust will require some very sophisticated baffling or lots of oil.

  28. Brian Sheridan says

    Ok Guys,
    Yes I did look at the photo of the frame, then I went down stairs to the shop an looked at all the bikes, 3 , and the sprocket location. All modern countershaft sprockets are generally slightly below the swing arm bolt centerline. The reason is that if they are above, the bike will squat under acceleration. If it squats, it’s not moving forward, and the steering head angle is effected, and the bike handle bad. A idler pulley will not help. Look at the dyno picture. The input shaft is connected to the countershaft. Now go out to your garage and see if that much engine could fit below on your bike? I think not. Guys, I say more power to this guy, but look how hard it was for Norton to get their bike to production. This seems like a lot of work for a one off. I wish I had that much time and money to play.

  29. Ted says

    Given the volume of the cylinders would there be any kind of a super charge effect with the dense fuel mixture being sucked down, I think there would be some, not much but some at higher RPM’s.

  30. giuliano says

    simply amazing! A motorcycle is not just a motor, even if the engineering team is known for its skill and expertise and will resolve all the issues raised here. It will be a wonderful bike … I’m sorry for “the others” !

  31. Scotduke says

    Another reason for inverted aero engines was for simplicity and ensure the prop could be bolted directly to the end of the crankshaft without need for gear drives. The Gypsy engines were highly reliable and many are still in use, having been manufactured from the late 1920s on. The same goes for the Walter Minor and Blackburn Cirrus engines, just in case anyone questions the long-term reliability of an inverted engine. I know the Gypsy engines are heavy oil users, which could partially result from fuel remaining in the combustion chamber.

    Keeping cylinder heads clean for this motorcycle engine won’t be much more of a problem than for engines with slanted heads though. And running a pressure washer over an engine every few runs isn’t a tough job.

  32. Ola says

    Interesting concept, especially the way the frame mounts to the engine. However, is it really an ideal engine for a motorcycle, given it’s weight and displacement? It seems more suited to a small car.

  33. Mule says

    At the risk of repeating a previous post: “If this is the answer, remind me again…what was the question?” Unique? Yes. Crazy different? Yes. Brian Sheridan is right on with the swing pivot/countershaft concern.

    Most sportbikes made today use the topends as stressed members but power and weight don’t seem to be much of a problem at all. Why re-invent the wheel to solve a problem that doesn’t exist. When untertaking a project of this scope (like the V8 Ducati), somewhere in the agenda should be an improvement over some shortcoming, also known as justification for all the effort. This project seems to have produced more new concerns than problem solving.

    I’m big on change and innovation, but the first filter it has to be run through is :Why do it?” Husaberg and Yamha are twisting their engine configurations around on a couple single cylinder dirtbikes, but with distinct purposes. Performance, plumbing, straightening intakes, mass centralization, etc. Not just to see if it can be done.

    My favorite comment? How do you get undernieth the thing to adjust the vales? I guess you could “Drop the cams”!

  34. Boog says

    The HP and torque figures are impressive for an engine of this size.(naturally aspirated with no power adders). Fitting this into a frame where you can lower the power take-off (sprocket) without some sort of primary chain arrangement, or perhaps a shaft (with the associated added weight and complexity) LOOKS like it might pose a challenge.

    But, whadda I know?

  35. joe says

    Love that air cooled engine ! The latest information on this project is, the design work is well under way on an upside down frame to house the upside down engine.

  36. nortley says

    This is an intriguing design, not that unusual except for orientation. I suppose a purge cycle could be programmed into the startup, a few revolutions before it gets fuel or fire, and by tracking starter current the brain could tell if a cylinder was hydroed and abort the start. Less seriously, could a combination of bottomed suspension and compressed tire make it into a flathead?

  37. BB says

    After measuring swingarm pivot height on my Blackbird and carefully reading engine measurements of this new engine I believe the front sprocket can be at the position shown in these pictures with no problems.
    Reading bike dry weight predictions, what’s wrong with a bike with 160-250 HP at less than 400lbs? Still concerned about torque?

  38. jp says

    Seems to me that there would have to be a jackshaft or something involved, given the apparent height of the countershaft above the swingarm pivot point. I can’t see this working out otherwise unless its mounted in a hardtail frame. I do like the crankcase as frame concept though.

  39. Bart says

    I have to agree with Mule on this one! Using the top ends of modern inline 4’s as stressed members is a no-problema way to go. The guy has solved a problem that doesn’t exist anymore, if it ever did at all. Nonetheless, it is cool (hot?) to look at, well executed metal craftsmanship.

    IMHO, having the hot section as shown creates hot spot problems because so much of the hot stuff is in the wind shadow of the motor. The pipes are gonna glow cherry red at stops and slow speeds/climbs. Any lube/fuel drips/leaks/spills/debris will start a fire back in the hot section. This has happened to me even with right-side-up motors!

    Will need NASA-spec fireproof chain lube too: the countershaft is right above a cherry-red exhaust header!

  40. Brian Sheridan says

    I assume that the cylinders and heads are Porsche, from a (pre twin cam) single cam air cooled model? If that is correct, at least they are starting with high level components. I reworked those heads years ago for IMSA endurance cars, and the quality of the parts was very high. I hope that these guys send Paul updated photo’s, so we can see how the project progress’s. If it all works, I’m certainly willing to eat my words. Since they are over the pond, someone should tell them to talk to Harris Fabrications in England. They are probably the best independent frame shop in Europe. If anyone could make this package work, it’s Harris.

  41. kneeslider says

    I’ve been in communication with Daniele since many of these comments appeared. His view is that taking a lot of time to convince everyone that what they are doing will work just fine would be far less productive for his small team than just continuing on with their work and then showing the completed engine and motorcycle. If they stay on schedule, we shouldn’t have to wait too long.

  42. David says

    Using the engine crankcase for a center section frame, sounds like an advantage in saving weight. However, as Honda found out in their first attempt at designing \Indy Cart\ open wheel racecars, with Honda race engines; a series problem existed in engine block distortion and shaft/bearing binding during racing. Too much stress was put on the engine block, that acted as a frame section replacement. Frames do twist and bend ever so sligthly, but asking an engine block to twist and bend, ever so slightly will put close tollerance bearings and shafts in a bind.

    Also to be considered is that placing most of the engine weight, transmision starter etc. high in the frame is going to raise the center of gravity.
    Deep water on the road combined with high temperature cylinder heads surely could short the spark plugs, make alot of steam and might even crack a head.
    An interesting experiment in thinking out of the box, but it does not get my endorsement for being practical.

  43. says

    Remember when Honda built the NSR500 with the gas tank below the motor
    and the light Ti exhaust up where the gas tank was? Remember how bad
    the bike handled?

  44. rohorn says

    Pat W,

    No, I never got the chance to race that bike. What was your experience with it?


    Thanks for relaying the designer/builder’s thoughts on the replies.

    Oh yes – this falls under the heading of new and interesting – thanks!!!!!!!!!!!!!!!

  45. Davidw says

    The small shaft diagonally above the countershaft looks suspiciously like a shift shaft. Should be an interesting mechanism. There’s a possibility someone involved with this project has more money than common sense.

  46. todd says

    Pat, luckily for Honda, they valued Fast Freddie’s opinion more than some people here apparently do.


  47. Nate says

    one thing sprang to mind on this: I sure hope the piston seals don’t go. This was a problem for radial engines in WW2. The lower pistons might fill with oil and when started, could blow the cylinder off the engine. Now there’s a way to start your day!

  48. Nando says

    Oh, well, I agree with Carlo 2763 is the legendary year in which Rome was founded!
    I’m from Rome too, and I missed it. Hope I can reach him and visit his little factory!

  49. Paulinator says

    How effective would ceramic coatings be at exiting the combustion heat from the middle cylinder?

    I hope what these guys are DOING blows holes in the general perception of \right\ side up. I’ll be cheering ’em on.

  50. rohorn says

    I’m guessing the Nembo people are getting a big laugh out of the FUD posted here – and that they knew that would be the reaction when they released the pictures to Paul.

    Oh yes – has anyone been outside in the last few years and seen where the shifter shaft enters the engine case on such bikes as the R1, R6, GSXR(fill in the blank), etc..?

    I would just love one of the keyboard dynamicists to explain what changing the CG actually does, the effects of change on the liveware, and how any of this applies to the above bike project:

  51. mule says

    rohorn, I’m not a “Dynamicist”, but I can say from experience that doing nothing more than putting a heavily loaded tankbag on your bike will have a serious adverse affect on a good handling bike. Start throwing the bike hard into corners and you’ll soon want to stop and chuck the tank bag into the bushes. Similarily, putting a loaded “Trunk” on a rear luggage rack, will also have serious consequences. You can’t fool nature. Raising the absolute heaviest single component 6-10″ from it’s traditional low point or alignment close to the axle centers WILL have an effect. I wouldn’t think it would be a positive affect, but maybe I’m still basing my opinion on actual experience and thinking inside the box.

    In reality, you could relocate the shift shaft anywhere on the bike you wanted. It would just require a more complex apparatus to tie it back into a reasonable shift lever location. Stacking transmissions and the current practice of compacting components is for mass centralization, not an attempt to raise the center of gravity per se. Centralizing mass on the roll center? Yes. But this is all being done as the weights of said components are plummeting, not just raising the CG. Generally speaking, raising CG on a bike has a serious adverse effect on weight transfer front to rear, which creates sometimes unsolvabale suspension setting solutions. And as with anything related to suspension tuning on a performance road bike, factors that have violent or sudden effects will be almost impossible to tune for. Massive sweeps in weight transfer would be one of those.

    With the upside down engine experiment, IF they get through all engineering challenges for what if any benefit has yet to determined, the next hurdles will be it affects on handling in the real world. That’s generally where much of the theory takes a backseat to the physical laws of stepping off the bike at speed in a corner.

    • rohorn says


      Sorry I missed your reply – I agree with what your well written thoughts. But:

      I think the shift shaft was placed there to use the identical system used in a number of available superbikes – I’m too lazy to look up which one, but it looks familiar – and is in the same place.

      The crank is, indeed a bit highed. But the cylinder head assembly – not a light unit – is a lot lower than the crank’s usual placement. I really can’t help but wonder if the engine’s CG is really that much higher than the same engine might be in a traditional layout.

      The bike’s CG is one thing – I like it low. I also like low seat heights for the same reason. Moving the rider’s CG – which is a LOT higher and heavier – is going to have a far greater effect than moving the engine’s CG. That’s why I always laugh at new model announcements when they say they moved the engine a few mm “for better handling”.

      So is this the Next Big Thing in motorcycle design? I don’t think so – but I could well be wrong. It is probably safe to assume the designers know a lot more about what they are doing than most of the commenters.

      Some people mentioned valve adjustment issues – just pick up the front end, sit down in front of it, and the valves are right there in your face!

  52. rafe03 says

    I seem to recall talk of pulling the prop backwards for a couple of turns before using the starter to crank the old radial & inverted engines to life. Same as they do with sprint cars even now a days. That would allow any accumulated oil, fuel, coolant, etc to be pushed out the exhaust valve to prevent “hydraulicking” when starting.

    Though I’ve never been there when a radial engine is being started, videos (think RENO Air Races or war movies) sometimes show a (large) blast of oily smoke emitted when the first couple of pots catch helping the others get their throat cleared out at the at the start. … (maybe Kevin Cameron can shed more light on this. I hear he’s bought a “CornCob engine to play with!)

    The K series of flat engines engines on BMW bikes are also known to smoke on starting as the bike leans to the left when on the side stand, allowing liquids to seep down into the combustion chamber.

    It’s been a year or so since the information on this engine has been updated. Any progress to report? I’m really intrigued by any thinking “outside the gunny sack” that gets proposed & this one is sure out there! Owner Daniele “Titus” Sabatini, Chief Engineer Giovanni Mariani, Chief Designer Fabio Falcone, Design Engineer Alessandro Sobacchi, Engine Designer Marco Fasaniof & their collective team at Nembo Motociclette have put a lot of time, effort & money into the “Super 32 rovescio” so far & I’d like to see it pay off!

    If that happens to be a Porsche SUHC head at the bottom of this, give them credit for recycling parts from the best!

  53. Big Sven says

    Just a thought: BMW had to pin the rings on their ‘Bricks’ to avoid oil leaking into the cylinders and smoking on start-up after being parked in the sidestand. As to the benefit of an upside-down engine, no comment really, only trying it will prove anything one way or the other. Re: high or low c of g, it is proven that a low c/g on a bike isn’t always the best solution. Bikes are not cars, bikes pivot around different yaw points (guessing at the right term!) The centre of yaw on a 2-stroke mx-bike is more or less just in front of the float-bowl of the carb. The idea of the Husaberg solution is to get the engine/gearbox gyroscopic forces as close to this point as possible. The wheels touching the ground contra the moment of yaw is cancelled-out by the rider holding the bars! An mx-bike in the air isn’t pivoting around the bottom of the tyres, but the moment of yaw. Footpeg and handlebar placement are far more important! I used to have a CX 500 and we all know how high a c/g THEY had. They hated greasy surfaces, you really needed the best tyres out there to feel reasonably safe, but that said it handled quiet well, never frightened me, but you had to really plan corners, it didn’t like being ‘flicked’ halfway around one like a Featherbed can. I recall Hailwood rode a CX on the island, as they were used as marshall’s bike one year and they said they weren’t good enough. He rode the wheels of it, saying it was a very good bike indeed, handled great, what were they moaning about, if only his race-bike was as good! But, yes, at 110mph it was a bit slow (usual tuned marshall’s bikes did 130 +)