<P> The Twin Cam initially was not used in the Softail model family before the year 2000 . This was due to the chassis design and vibration transfer to the Softail frame as a result of the direct (hard) mounting of the engine . Dyna models are "rubber mounted", damping the majority of vibration transfer to the frame and rider . Another reason was that the engine and transmission on a Twin Cam are directly bolted (but are still separate units) to each other, with the chassis seat post on a Softail getting in the way of a Twin Cam transmission case . As the company determined that a rubber - mounted Softail would affect the line's visual styling, Harley solved the issue by designing an engine variant known as Twin Cam 88B . It is basically the same engine as the original (now retroactively referred to by enthusiasts as "Twin Cam 88A"), but with a modified engine block design that incorporates twin chain - driven balance shafts . The Twin Cam 96B engine was released at the same time as the Twin Cam 96A model, for the 2007 model year, and was equipped on all Softail models until it was replaced by the 103 ci version . </P> <P> It is possible, however, to mount a regular Twin Cam motor to a pre-2000 Softail (or any chassis that accepts an Evolution engine), through third - party adapters . </P> <P> The engine design differed considerably from its predecessor the "Evo" although it shared some design elements with the Sportster line . The 88 represents the displacement in cubic inches of the standard engine . The bore is 95.3 mm (3.75 in) and the stroke is 101.6 mm (4.00 in), meaning the displacement is 88 cu in (1,450 cc). The Twin Cam 96 displaces 96.7 cu in (1,584 cc). The company released 103 cu in (1,690 cc) for 2010 Electra Glide Ultra Limited models, and later for 2012 Softail models and 110 cu in (1,801 cc) for Screamin' Eagle / CVO Models . </P> <Table> <Tr> <Th> Change </Th> <Th> Evo </Th> <Th> Twin Cam </Th> </Tr> <Tr> <Td> Displacement </Td> <Td> 82 cu in (1,340 cc) </Td> <Td> 88 cu in (1,450 cc), 96 cu in (1,584 cc), 103 cu in (1,690 cc), 110 cu. in . (1,801 cc). </Td> </Tr> <Tr> <Td> Oil pump </Td> <Td> External . Connected through a series of gears . </Td> <Td> Internal twin - gerotor . Connected directly to the right side pinion shaft . This pump is more efficient, maintains a higher pressure and larger volume . </Td> </Tr> <Tr> <Td> Cams </Td> <Td> Single, with 4 lobes . </Td> <Td> One per cylinder, each with 2 lobes . This allows the push rods to be better aligned with the rocker arms . </Td> </Tr> <Tr> <Td> Cam drive </Td> <Td> Gears </Td> <Td> Silent chain . This change was reported as necessary to meet EPA noise requirements . Many users installed after market gear driven replacements to increase timing accuracy . </Td> </Tr> <Tr> <Td> Transmission attachment </Td> <Td> Displaced from motor </Td> <Td> Transmission casing is attached directly to the engine . </Td> </Tr> <Tr> <Td> Oil tank </Td> <Td> Usually surrounds battery box under the seat . </Td> <Td> Below and behind the transmission assembly (except Softails, which are same as noted for the Evo) </Td> </Tr> <Tr> <Td> Combustion chamber </Td> <Td> "D" shape </Td> <Td> "Bathtub" shape . Allowed for more efficient combustion and has higher compression . </Td> </Tr> <Tr> <Td> Spark firing </Td> <Td> Wasted spark (both plugs fire at the same time). The ignition system uses single coil . Plugs are 14 mm (0.55 in). </Td> <Td> No wasted spark . The ignition system employs dual coils . Plugs are 12 mm (0.47 in). </Td> </Tr> <Tr> <Td> Cooling </Td> <Td> Air - cooled </Td> <Td> Also air - cooled . Increased cooling fin areas and an oil jet that sprays the bottom of the pistons provide additional cooling capability . </Td> </Tr> </Table>

When did harley come out with the 103