From a technical perspective, and we are going to get a little technical here, the 1000 DS motor is an all-new 992cc 90-degree L-Twin. With the new engine Ducati had
been aiming for more power, simplified mechanicals, lower engine temperatures, more reliability, lower emissions and lighter weight. I can safely say that they have achieved much of what they set
out to do. The air-cooled design has obvious advantages in relation to simplicity
and the fact that radiators, water pumps and associated hoses are not needed. Lighter weight is a result, as is easier access to the engine for servicing. The minus side of the equation is that
air-cooled engines normally produce less power, and generally run looser tolerances to allow for the wider variations in operating temperature.
Inside the new cylinder heads the camshafts
now run on pressurised plain bearings instead of the ball bearing arrangement found on the previous engine. This of course has reduced weight and the number of moving parts, which in turn serves to
increase reliability. The 1000 DS runs significantly higher oil pressure and volume with a new oil pump and passages. The higher pressure is required by the plain bearing camshafts but also aids in
engine cooling and reliability. A pair of spark plugs reside in each cylinder head which aids clean combustion.
Valve angle has been reduced which lends to a more externally compact cylinder
head. Inside the new high-compression combustion chambers the valves have actually increased in size. Intake valves have grown from 43 to 45mm and exhaust valves from 38 to 40mm. The new larger
valves are also lighter due to the fact that the stems are now only 7mm in diameter, the same stems are used in the Ducati superbike engines.
Feeding the bigger inlet valve is a larger
intake port. The exhaust port is also larger in diameter but is 40% shorter in length, this helps to reduce the engine temperature as the hot exhaust gases are cleared from the cylinder heads much
more quickly.
The valve seats are now made of beryllium bronze and offer improved heat dispersion and wear characteristics. This allows valve clearances to be more accurately maintained over
the service life of the engine. More aggressive camshafts operate those valves via Ducati’s trademark Desmodromic actuation system. The timing belt gears now have 20 teeth, two more than before, and
are now more smoothly routed, while new tension rollers have built in bearings with improved seals. A new mounting system makes servicing easier. The cylinder head is now sealed to the cylinder via
a metal gasket, eliminating o-rings and simplifying assembly.
New pistons with nitrided steel rings reside in a 94mm bore and slide through a 71.5mm stroke. The previous 900SS engine had a
bore/stroke of 92/68mm. The cylinder barrel is now thicker and more rigid while fin extensions have been added to the lower part of the cylinder for better support when the piston is at the bottom
of its stroke. New connecting rods are made from 30NiCrMo4. This material allows a much stronger and consistent forging. In cross section the new rods are thinner side-to-side but wider fore to aft
with a stronger I-beam design, which helps to provide more strength while also reducing weight. The crankshaft is also new and the oil delivery ports to the main bearings have been positioned in
less structurally critical areas of the crankcase which allows for more rigidity of the crank. This helps to further reduce vibration and increase longevity.
Continued... |
