Source: Cycle World
What would you like to see this single in? (Ducati/)Ducati has a long and well-deserved reputation as an innovative engineering company, going all the way back to 1954 with Fabio Taglioni (the famous “Doctor T”) and the iconic desmodromic valve-actuation system that has become such an icon of the Italian company. Now, 70 years later, we explore the new Ducati Superquadro Mono 698 single, the latest example of Ducati’s technologic savvy, best evidenced by one principal fact: This 659cc single-cylinder engine revs to 10,000 rpm and more.Today Ducati is a company famous for its V-twin engines, yet the idea for this new engine goes back some five years. At the end of a meeting, Ducati CEO Claudio Domenicali asked if anyone had a suggestion for a new model, and one brave soul dared raise the idea of a single. Of course it would have to be the hottest single on the market, so it’s only natural that the engine’s basic technology derives from the mighty Panigale 1299 V-twin, one of the most advanced and powerful production twins ever.The new Ducati 698 is relatively compact for its displacement, and appreciably light as well. Externally its design is squarish and functional, especially when compared to the elegant, aesthetically harmonious singles Taglioni designed in the 1950s and ‘60s. Generating 77.5 hp at 9,750 rpm in stock form, when fitted with a Termignoni racing exhaust that number surges to 84.5 hp at 9,500 rpm. This is way above any other single, including KTM’s excellent 690 which delivers 74 hp at 8,000 rpm. With a highly oversquare 116mm bore and 62.4mm stroke it’s easy to see why the redline is sky high—at peak power the piston mean speed is 66.3 feet per second, well within the traditionally accepted safe limits of 78–79 feet per second. By comparison, with its 80mm stroke the KTM 690 reaches about 70 feet per second at peak power.While its power numbers are outstanding, the Ducati 698 doesn’t shine as brightly when it comes to torque, producing 46.5 lb.-ft. of peak torque at 8,050 rpm (49.4 lb.-ft. with the Termignoni exhaust). Here the KTM holds a clear advantage: a very strong 54 lb.-ft. at 6,500 rpm.Related: 2024 Ducati Hypermotard 698 Mono First Ride ReviewA Look Inside, the Crankcase and CylinderInside the left side of the crankcase. (Bruno dePrato/)Disassembly reveals the Ducati 698 Superquadro to be a feast for both the art lover and the engineer. As with the Panigale twin, the die-cast crankcase is vertically split. Look carefully at how the cylinder too is split, and incorporated into each crankcase half. This significantly improves rigidity, and bolting the head directly to the crankcase helps eliminate any parasitic vibrations.A 116mm piston moves through 62.4mm. (Bruno dePrato/)The one-piece cylinder liner is a high-tensile aluminum alloy element with a Gilardoni Cermetal bore treatment, the Italian variation of Nikasil.The Piston and Con-rodThe bridged-box structure of the Superquadro’s piston. (Bruno dePrato/)The 116mm piston features two rings, a short skirt, and a stiffened bridged-box inner structure. Weight is a positive 649 grams, including the steel wrist pin, the latter with a diamond-like coating (DLC) for minimal friction. The piston derives directly from the Panigale 1299, and is cooled via oil jet.The Superquadro uses a forged connecting rod. (Bruno dePrato/)The con-rod is sinter-forged from powdered metal and weighs 607 grams. Its stem is slightly leaner than the 1299′s rod. The small end is 29.2mm wide and perfectly symmetrical, while on the 1299 it was slightly offset. Compared to the 1299 part, the major difference is in the center-to-center measurement: In the single it’s 109.3mm, while with the twin it’s 110mm. This is because the single’s stroke has grown from the Panigale’s 60.8mm to 62.4mm. Consequently, the rod’s length-to-stroke ratio drops from 1.81:1 down to 1.75:1. The Panigale’s 1.81:1 is already pretty short in relation to the huge bore and high revs, and thus the single’s 1.75:1 ratio is very short given the same bore. Offsetting the piston pin can help with the piston side thrust, but a stroke-rod length ratio below 2:1 always increases secondary-order imbalance and related vibration.With any big single, primary- and secondary-order imbalances are always substantial. Including a pair of balance shafts in the design can cancel a good percentage of the primary-order-imbalance-generated vibrations, but nobody wants to add an additional pair of balancing shafts to kill secondary-imbalance vibrations. Such balancers should turn at twice the crank’s speed—meaning an unrealistic 20,500 rpm in this case. Increasing the rod’s center-to-center length is the most rational solution… But that makes the engine taller. Is it worth the trade-off? Dr. Taglioni thought it was.The Cylinder HeadDucati 698cc Superquadro Mono combustion chamber shows small squish area (Bruno dePrato/)The combustion chamber duplicates the 1199/1299 design, featuring enormous paired 46.8mm intake and 38.2mm exhaust valves, each weighing 49 and 67 grams, respectively. (The 1299 R Final Edition had even bigger valves at 48mm and 39.5mm.) Inlet valves are titanium, sourced from US specialist Del West Engineering, while the exhaust valves are steel. Included-valve angle is 23 degrees, allowing for a 13.1:1 compression ratio with a nearly flat piston top. The combustion chamber is thin and features small squish areas due to the large valves.Seeing valve size dictate combustion chamber shape like this confirms that the Ducati engineers emphasized volumetric efficiency over thermodynamic efficiency. Looking at the torque numbers bears this out: Specific torque here is 70.5 lb.-ft. per liter, much lower than the 84 lb.-ft. per liter generated by the 1299. The moderate specific-torque output is partly made up for by the engine’s ability to rev past 10,000 rpm.The Ports and Throttle BodyLooking down the intake ports. (Bruno dePrato/)Compared with the 1299, the single’s inlet-port size is reduced. The oval throttle body is derived from the 959 Panigale twin, and its area corresponds to a round throttle body measuring 62mm. This is down from the 67.5mm throttle body of the 1299, and may partly explain the reduced specific-torque output. The intake runners are set at an average 25-degree angle to the valve stem—very similar to the configuration of the inlet ports in the old two-valve engines, selected here to improve tumble turbulence.Reducing the throttle-body size improves the torque-curve profile by inducing a higher inertia in the incoming charge. Given the profile and the geometric setting of the inlet runners, retarding intake-valve timing might induce a strong swirl turbulence to improve the combustion at middle revs along with the torque curve as well.The CamsTop view of the Superquado Mono’s four-valve head. (Bruno dePrato/)A DOHC four-valve desmo head is always a piece of mechanical jewelry. Here the new 698 Superquadro shares the same basic design as the 1299 Panigale twin. A Morse Hy-Vo chain drives from the crankshaft to an intermediate sprocket, and from there two gears drive the camshafts, each camshaft supported by two aluminum bearings. The closing-cam lobes are duly lightened on the portion unloaded during the cycle. During starting the exhaust camshaft actuates a decompressor system which allows the use of a smaller starter motor. On the right side of the inlet camshaft is the valve controlling transfer of blow-by fumes to the exhaust system.The CrankshaftThe Superquadro’s forged crankshaft. (Bruno dePrato/)A short and strong crankshaft. (Bruno dePrato/)The short, massive crankshaft shares some basic dimensions with the 1299, but not all. The stroke has grown from 60.8mm to 62.4mm. Crank-throw journal diameter is 45mm (the same as the big twin, as is the 50mm main-end journal on the primary-transmission side), while the main-end journal on the alternator side has been reduced from 50mm to 45mm. The crank journal and the main-end journals now feature a slightly reduced overlap in the axial view, but at no detriment to rigidity given the reduced width of the crank journal. The crankshaft weighs 3,820 grams (8.42 pounds).The Starter DrivetrainThe two balancing shafts are gear-driven. (Bruno dePrato/)The gear driving the balancing countershafts is interference-pressed onto the crank’s left end—a new construction technique for Ducati. The single-piece forged balancing countershafts weigh 578 grams (1.274 pounds) and 489 grams (1.08 pounds), respectively.Layout of the starter system. (Bruno dePrato/)Given the high loads that occur when starting a huge single like this, the 698′s starting system is necessarily deliberate. The starter motor turns a high-reduction-ratio intermediate gear that in turn drives the gear machined into the right-hand balancing countershaft, again with a high reduction ratio. Finally the balancing shaft drives the crankshaft at 1:1 (no reduction). The intermediate gear is driven by the electric starter motor and incorporates a small diaphragm-type clutch that interrupts the connection to the electric starter motor in case of kickback recoil.
Full Text:
What would you like to see this single in? (Ducati/)
Ducati has a long and well-deserved reputation as an innovative engineering company, going all the way back to 1954 with Fabio Taglioni (the famous “Doctor T”) and the iconic desmodromic valve-actuation system that has become such an icon of the Italian company. Now, 70 years later, we explore the new Ducati Superquadro Mono 698 single, the latest example of Ducati’s technologic savvy, best evidenced by one principal fact: This 659cc single-cylinder engine revs to 10,000 rpm and more.
Today Ducati is a company famous for its V-twin engines, yet the idea for this new engine goes back some five years. At the end of a meeting, Ducati CEO Claudio Domenicali asked if anyone had a suggestion for a new model, and one brave soul dared raise the idea of a single. Of course it would have to be the hottest single on the market, so it’s only natural that the engine’s basic technology derives from the mighty Panigale 1299 V-twin, one of the most advanced and powerful production twins ever.
The new Ducati 698 is relatively compact for its displacement, and appreciably light as well. Externally its design is squarish and functional, especially when compared to the elegant, aesthetically harmonious singles Taglioni designed in the 1950s and ‘60s. Generating 77.5 hp at 9,750 rpm in stock form, when fitted with a Termignoni racing exhaust that number surges to 84.5 hp at 9,500 rpm. This is way above any other single, including KTM’s excellent 690 which delivers 74 hp at 8,000 rpm. With a highly oversquare 116mm bore and 62.4mm stroke it’s easy to see why the redline is sky high—at peak power the piston mean speed is 66.3 feet per second, well within the traditionally accepted safe limits of 78–79 feet per second. By comparison, with its 80mm stroke the KTM 690 reaches about 70 feet per second at peak power.
While its power numbers are outstanding, the Ducati 698 doesn’t shine as brightly when it comes to torque, producing 46.5 lb.-ft. of peak torque at 8,050 rpm (49.4 lb.-ft. with the Termignoni exhaust). Here the KTM holds a clear advantage: a very strong 54 lb.-ft. at 6,500 rpm.
Related: 2024 Ducati Hypermotard 698 Mono First Ride Review
A Look Inside, the Crankcase and Cylinder
Inside the left side of the crankcase. (Bruno dePrato/)
Disassembly reveals the Ducati 698 Superquadro to be a feast for both the art lover and the engineer. As with the Panigale twin, the die-cast crankcase is vertically split. Look carefully at how the cylinder too is split, and incorporated into each crankcase half. This significantly improves rigidity, and bolting the head directly to the crankcase helps eliminate any parasitic vibrations.
A 116mm piston moves through 62.4mm. (Bruno dePrato/)
The one-piece cylinder liner is a high-tensile aluminum alloy element with a Gilardoni Cermetal bore treatment, the Italian variation of Nikasil.
The Piston and Con-rod
The bridged-box structure of the Superquadro’s piston. (Bruno dePrato/)
The 116mm piston features two rings, a short skirt, and a stiffened bridged-box inner structure. Weight is a positive 649 grams, including the steel wrist pin, the latter with a diamond-like coating (DLC) for minimal friction. The piston derives directly from the Panigale 1299, and is cooled via oil jet.
The Superquadro uses a forged connecting rod. (Bruno dePrato/)
The con-rod is sinter-forged from powdered metal and weighs 607 grams. Its stem is slightly leaner than the 1299′s rod. The small end is 29.2mm wide and perfectly symmetrical, while on the 1299 it was slightly offset. Compared to the 1299 part, the major difference is in the center-to-center measurement: In the single it’s 109.3mm, while with the twin it’s 110mm. This is because the single’s stroke has grown from the Panigale’s 60.8mm to 62.4mm. Consequently, the rod’s length-to-stroke ratio drops from 1.81:1 down to 1.75:1. The Panigale’s 1.81:1 is already pretty short in relation to the huge bore and high revs, and thus the single’s 1.75:1 ratio is very short given the same bore. Offsetting the piston pin can help with the piston side thrust, but a stroke-rod length ratio below 2:1 always increases secondary-order imbalance and related vibration.
With any big single, primary- and secondary-order imbalances are always substantial. Including a pair of balance shafts in the design can cancel a good percentage of the primary-order-imbalance-generated vibrations, but nobody wants to add an additional pair of balancing shafts to kill secondary-imbalance vibrations. Such balancers should turn at twice the crank’s speed—meaning an unrealistic 20,500 rpm in this case. Increasing the rod’s center-to-center length is the most rational solution… But that makes the engine taller. Is it worth the trade-off? Dr. Taglioni thought it was.
The Cylinder Head
Ducati 698cc Superquadro Mono combustion chamber shows small squish area (Bruno dePrato/)
The combustion chamber duplicates the 1199/1299 design, featuring enormous paired 46.8mm intake and 38.2mm exhaust valves, each weighing 49 and 67 grams, respectively. (The 1299 R Final Edition had even bigger valves at 48mm and 39.5mm.) Inlet valves are titanium, sourced from US specialist Del West Engineering, while the exhaust valves are steel. Included-valve angle is 23 degrees, allowing for a 13.1:1 compression ratio with a nearly flat piston top. The combustion chamber is thin and features small squish areas due to the large valves.
Seeing valve size dictate combustion chamber shape like this confirms that the Ducati engineers emphasized volumetric efficiency over thermodynamic efficiency. Looking at the torque numbers bears this out: Specific torque here is 70.5 lb.-ft. per liter, much lower than the 84 lb.-ft. per liter generated by the 1299. The moderate specific-torque output is partly made up for by the engine’s ability to rev past 10,000 rpm.
The Ports and Throttle Body
Looking down the intake ports. (Bruno dePrato/)
Compared with the 1299, the single’s inlet-port size is reduced. The oval throttle body is derived from the 959 Panigale twin, and its area corresponds to a round throttle body measuring 62mm. This is down from the 67.5mm throttle body of the 1299, and may partly explain the reduced specific-torque output. The intake runners are set at an average 25-degree angle to the valve stem—very similar to the configuration of the inlet ports in the old two-valve engines, selected here to improve tumble turbulence.
Reducing the throttle-body size improves the torque-curve profile by inducing a higher inertia in the incoming charge. Given the profile and the geometric setting of the inlet runners, retarding intake-valve timing might induce a strong swirl turbulence to improve the combustion at middle revs along with the torque curve as well.
The Cams
Top view of the Superquado Mono’s four-valve head. (Bruno dePrato/)
A DOHC four-valve desmo head is always a piece of mechanical jewelry. Here the new 698 Superquadro shares the same basic design as the 1299 Panigale twin. A Morse Hy-Vo chain drives from the crankshaft to an intermediate sprocket, and from there two gears drive the camshafts, each camshaft supported by two aluminum bearings. The closing-cam lobes are duly lightened on the portion unloaded during the cycle. During starting the exhaust camshaft actuates a decompressor system which allows the use of a smaller starter motor. On the right side of the inlet camshaft is the valve controlling transfer of blow-by fumes to the exhaust system.
The Crankshaft
The Superquadro’s forged crankshaft. (Bruno dePrato/)
A short and strong crankshaft. (Bruno dePrato/)
The short, massive crankshaft shares some basic dimensions with the 1299, but not all. The stroke has grown from 60.8mm to 62.4mm. Crank-throw journal diameter is 45mm (the same as the big twin, as is the 50mm main-end journal on the primary-transmission side), while the main-end journal on the alternator side has been reduced from 50mm to 45mm. The crank journal and the main-end journals now feature a slightly reduced overlap in the axial view, but at no detriment to rigidity given the reduced width of the crank journal. The crankshaft weighs 3,820 grams (8.42 pounds).
The Starter Drivetrain
The two balancing shafts are gear-driven. (Bruno dePrato/)
The gear driving the balancing countershafts is interference-pressed onto the crank’s left end—a new construction technique for Ducati. The single-piece forged balancing countershafts weigh 578 grams (1.274 pounds) and 489 grams (1.08 pounds), respectively.
Layout of the starter system. (Bruno dePrato/)
Given the high loads that occur when starting a huge single like this, the 698′s starting system is necessarily deliberate. The starter motor turns a high-reduction-ratio intermediate gear that in turn drives the gear machined into the right-hand balancing countershaft, again with a high reduction ratio. Finally the balancing shaft drives the crankshaft at 1:1 (no reduction). The intermediate gear is driven by the electric starter motor and incorporates a small diaphragm-type clutch that interrupts the connection to the electric starter motor in case of kickback recoil.
