Harley Davidson 103 Twin Cam Engine Diagram

Harley-Davidson is introducing the Twin Cam 103™ engine, a powertrain rated at 100 ft. lbs. of torque at 3500 RPM and featuring Electronic Sequential Port Fuel Injection (ESPFI), as standard equipment on all 2012 Softail® and Touring motorcycle models with the exception of the Dyna Street Bob® and Dyna Super Glide® Custom.

The new Twin Cam 103 powertrain delivers greater performance for riders, providing up to 6 percent more peak torque than its predecessor, the Twin Cam 96 engine it replaces as standard power for many of these models. It also features identifying badges on the derby cover, timer cover and air cleaner trim ring in addition to an automatic compression release system.

All Harley Davidson Softail models feature this enhanced performance boost in 2012 along with ergonomic improvements such as a reduced-reach handlebar for Fat Boy and Fat Boy Lo riders that places them “in the bike” position while enjoying a lower, narrower seat shape design. Additionally, both Deluxe and Heritage Softail Classic will feature optional “tubeless” Chrome Aluminum Profile Laced wheels which are designed to make tire replacement or repair easier than ever before.

For Touring model riders seeking increased passing power on their rides, they have access to all benefits offered by Twin Cam 103 including oil cooling system integration so they can enjoy improved overall performance when needed most. By equipping its entire range of motorcycles with this powerful new engine technology in 2012 Harley-Davidson 103 has solidified itself among top tier motor cycle manufacturers worldwide..

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Harley Davidson 103 Twin Cam Features and Benefits

Harley Davidson Twin Cam 103 Features and Benefits
Harley-Davidson Twin Cam 103 Features and Benefits


The Harley Davidson® Twin Cam 103 engine boasts a powerful punch of performance and the signature rumble that riders have come to expect. Featuring Electronic Sequential Port Fuel Injection jetting, this air cooled engine delivers crisp throttle reaction for quick acceleration when passing or climbing hills, even with extra weight. The low cruising rpm also ensures smoother riding experiences with less engine vibration and better fuel efficiency on the highway.

This combination of power, torque and style provides a unique experience for any rider who is looking for something special from their bike. With more pull from every twist of the accelerator, you’ll feel like your ride has been taken to another level when you experience it first hand.



The Motor Company’s expertise in understanding what makes an engine truly move a rider is unparalleled, and that knowledge was applied to the development of the Twin Cam 103 engine. After extensive research and design, this new addition has provided improved performance and durability without sacrificing any of Harley-Davidson’s iconic styling. The technology used for this engine builds upon the legacy left by earlier models such as the Flathead, Knucklehead, Panhead, Shovelhead®, Evolution®, Twin Cam 88® and Twin Cam 96™ engines. This impressive powertrain directly benefits from over a century worth of devoted engineering experience with V-Twin engines since 1909 – testament to The Motor Company’s commitment to life on two wheels.



Harley-Davidson’s Twin Cam 103 engine is a powerful and reliable machine with refined performance. Its lightweight piston design allows for increased power delivery, while the Six-Speed Cruise Drive® transmission gives riders six options to choose from. This combination of components offers low routine maintenance and low cruising rpm that lets riders take full advantage of the bike’s capabilities.

The Twin Cam 103 engine provides an impressive amount of torque when fired up, giving users control over their biking experience. With its well-designed driveline and strong internal parts, Harley-Davidson ensures that each ride is smooth, responsive, and enjoyable. Whether you’re looking for a leisurely cruise or a high-powered adrenaline rush, the Twin Cam 103 has you covered every time.



The Twin Cam 103™ engine is a sight to behold. It has been designed with great attention to detail, ensuring that the iconic Harley-Davidson style shines through in all its glory. The black powder coated heads and cylinders are framed by machined cooling fin tips and gleaming polished rocker covers, making it truly stand out as an impressive piece of engineering.

In addition to its visual appeal, this engine also boasts considerable power – something which can be seen in everything from the classic edge of the cooling fins to the clean lines of cases and covers. As such, it makes a strong statement on staying true to what one knows will satisfy them most.

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One of the most sought-after features in a motorcycle is that it should be able to rumble when pushed. The Six-Speed Cruise Drive from [Company Name] provides just that, allowing riders to experience a smooth and quiet shift while reducing engine speed on the highway. In addition, its Isolated Drive System ensures acceleration is delivered in steady streams directly from the rider’s wrist to the pavement. This rare blend of power and responsiveness gives riders a unique sensation as they cruise down their chosen roads, with an accompanying low growl keeping them company along the way.

For those looking for both performance and comfort in one package, this combination of components supplies an ideal solution for any ride. With high levels of control over responsiveness and engine speed provided by these two systems, plus efficient energy usage and excellent noise reduction capabilities, it is no wonder why so many motorists are choosing this model for their excursions.

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2012 Harley-Davidson Twin Cam 103 USA Specifications

2012 Harley Davidson Twin Cam 103 USA Specifications
2012 Harley-Davidson Twin Cam 103 USA Specifications

US MSRP Price: See Dealer for pricing

  1. The ground clearance of 4.3 inches (110 mm) is perfect for navigating tight corners when riding.
  2. The rake angle of 29.9° ensures a smooth ride and effortless steering control, while the fork angle of 28.9° provides optimal stability and balance on the road.
  3. The trail length at 5.84 inches (148.3 mm) helps riders to maintain confidence in their handling abilities even during difficult maneuvers or turns at high speeds .
  4. At 62.8 inches (1595 mm), the wheelbase offers increased turning capabilities without compromising stability or maneuverability when traversing wet surfaces or rough terrain .
  5. For added safety and performance, Dunlop® Harley-Davidson® Series tires are installed as standard – with a 130/70B18 63H front tire and a 160/70B17 73H rear tire for maximum grip and control over any surface imaginable
  6. The fuel capacity is rated at 4..7 gallons (17..8 liters) – with a warning light that activates once the tank reaches 0..9 gallons remaining
  7. Engine oil capacity stands at 3 quarts (.95 liters), while both transmission fluid capacity and primary chain case capacity come in 1 quart (.95 liters).


  1. The Harley-Davidson Twin Cam 103™ engine features air-cooled, pushrod-operated overhead valves with hydraulic, self adjusting lifters and two valves per cylinder.
  2. This powerful powerhouse boasts a bore x stroke of 3.875 in. x 4.38 in (98.4 mm x 1113 mm), for a total displacement of 103 cubic inches (1690 cc).
  3. With an impressive compression ratio of 9:6:1, the Twin Cam 103™ is designed to provide optimal power output from its Electronic Sequential Port Fuel Injection system (ESPFI).
  4. An efficient fiberglass media air cleaner offers superior protection against harsh contaminants while pressurized dry sump lubrication ensures smooth operation at all times – even under tough conditions!
  5. From touring bikes to cruisers and custom choppers, the Harley-Davidson Twin Cam 103™ engine provides dependable performance as well as excellent fuel economy – perfect for any type of ride you might be looking for!


  1. Motorcycles fitted with Primary Drive Chain, 34/46 ratio Final Drive Belt, 32/66 ratio Clutch Multi-plate and wet Transmission 6-Speed Cruise Drive® Gear Ratios feature a six speed transmission for smooth acceleration and shifting experience.
  2. The primary drive chain has a 34: 46 ratio that helps transfer power from the engine to the rear wheel quickly and efficiently.
  3. The final drive belt is equipped with a 32: 66 ratio which ensures improved grip on uneven surfaces while making sharp turns or riding over rough terrain.
  4. To reduce wear and ensure durability, the clutch multi-plate is designed as a wet system that keeps friction between moving parts low during shifts in gear ratios (overall).
  5. With U.S.-based overall gear ratios of 9: 311 – 2nd 6: 454 – 3rd 4: 793 – 4th 3: 882 – 5th 3: 307–6th 2: 79, riders can take advantage of optimal performance across all speeds whether they are taking off from standstill or cruising at higher speeds safely on highways!


  1. Engine Torque: The torque for the North American market is 100 ft-lbs @ 3500 RPM (136 Nm @ 3500 RPM).
  2. Lean Angle: This vehicle boasts a right and left lean angle of 29° each, according to J1168 standards.
  3. Fuel Economy: The EPA has rated this vehicle with an urban/highway fuel economy of 42 mpg (5.6 L/100 km).
  4. Durability: This engine was designed to withstand long periods of use without any issues or performance degradation over time.
  5. Reliability: With its cutting edge design and regular maintenance scheduled, this engine can provide reliable service for years to come with minimal repairs needed along the way for optimal efficiency and safety results on the road or highway driving conditions alike.
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2012 Harley-Davidson Twin Cam 103 – Canadian Specifications

MSRP Price: See dealer for pricing.


  1. The Harley-Davidson® Twin Cam 103™ engine is air-cooled, with a bore of 98.4 mm and a stroke of 111.1 mm.
  2. Its displacement is 1,691 cc and its compression ratio is 9.6:1 for optimal performance on the road or track.
  3. It features Electronic Sequential Port Fuel Injection (ESPFI), providing an even distribution of fuel to ensure maximum power output from the engine at all times during operation .
  4. The Twin Cam 103™ also has superior durability due to its advanced cooling system that keeps the engine running cooler than other engines on the market today .
  5. With excellent torque delivery and improved acceleration, this engine provides riders with an exciting ride no matter what speeds they choose to go at!
  6. Built using only high quality materials and components, it’s designed to last longer than many other engines available in the same class — giving owners years of reliable riding pleasure!


  1. Primary Drive Chain with a 34/46 ratio is an ideal choice for motorcycles, ATVs and UTVs that require increased acceleration and torque.
  2. The overall gear ratios in this chain are 9.311 for first, 6.454 for second, 4.793 for third, 3.882 for fourth, 3.307 for fifth and 2.79for sixth gears respectively; providing superior performance on the track as well as roads alike!
  3. With such excellent gear ratios these chains offer better power delivery to the rear wheels of your vehicle resulting in improved acceleration times and higher top speeds – making them perfect choice if you’re looking to upgrade or build a race-ready bike!
  4. The added strength of the steel used in manufacturing this primary drive chain means it can easily handle high-stress applications without compromising quality or longevity – so you can be sure they’ll last season after season!
  5. The heat treatment applied during production further increases its durability while also reducing wear over time; giving you peace of mind even when pushed hard on tight tracks or challenging terrain!
  6. The double X shaped link design ensures greater stability at high speeds by reducing stretching – enabling more efficient energy transfer from engine to wheels ensuring maximum control no matter what conditions may prevail!


  1. The J1349 engine torque testing method is a reliable way to measure the performance of an engine.
  2. It involves measuring the torque at 3,500 RPM, as well as both lean angles (29 degrees left and right).
  3. This test produces a result of 136 Nm for the engine torque, providing valuable data on how efficiently it performs under various scenarios and conditions.
  4. To ensure accuracy, multiple readings should be taken from different points in order to get an average value that accurately represents the true performance of an engine’s power output.
  5. By using this testing method, fuel economy can also be determined- with results showing 5.6 l/100 km combined city/hwy ratings when tested on a specific vehicle model or type of car being evaluated..
  6. This technique is useful for mechanics and technicians who need to evaluate engines quickly and efficiently without having to run through lengthy diagnostic processes or tear apart components in order to identify issues or faults with them before they can be fixed correctly by trained professionals working on such machinery..
  7. Overall ,the J1349 Engine Torque Testing Method provides accurate results that are invaluable when assessing the effectiveness or efficiency of any given motor system – allowing experts and mechanics alike gain insight into its overall condition so that any necessary repairs can be made swiftly and effectively – all while meeting safety regulations too!
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