The S&S® engine you have purchased is an air-cooled, v-twin. It is designed to offer Proven Performance® and reliability. Specifications for the 31⁄2", 35⁄8", 4", and 41/8" bore engines are found in this manual. We have covered the most popular configurations, 80ci, 96ci, 111ci, and 124ci, based on their original S&S production designs. Some changes may have been made over time as these engines have been in production for a number of years. The specifications in this manual are based on the most recent production specifications.


The procedure for installing an S&S engine is basically the same as outlined in the factory service manual for the model of motorcycle the engine is being installed in. However, S&S engines are sometimes taller then a stock engine so the installer must check to make sure there is adequate clearance between the engine and all chassis components including the frame and fuel tanks. An upgraded clutch should also be considered, since the S&S engine will produce more power than the stock engine it is replacing.


The following diagrams show how the crankcase breather and oil lines should be hooked up for S&S V-Series engines. Note most 41/8" bore engines have a use a vacuum breather system


Ambient Temperature (°F)

SAE 20W50Above 30°–100°
SAE 50Above 60°–100°
SAE 25W60Above 80°
SAE 60Above 80°


S&S recommends synthetic engine oil such as S&S Premium Synthetic 20W50. However a premium petroleum based engine oil such as S&S Heavy Duty 20W50 or 25W60 is acceptable.

Regardless of what type of oil you select, be sure to use only oil specifically designated for use in an air-cooled motorcycle, and select the viscosity suggested for the temperature range you will be operating your motorcycle in.

The oil filter used on an S&S® V-Series engine should be rated at 24 microns. Spin-on filters should not have an anti-drain back valve. S&S filters are available to replace Harley-Davidson® #63805-80A and 63796-77A. The S&S part numbers are 31-4101 and 31-4102.




The gasoline used in your engine should have a US octane rating of 91 or higher. The United States uses the method  (R+M)/2 of octane rating. In many countries outside the United States, the RON (Research Octane Number) is used, which will result in a higher octane requirement of about 96.


  • Remember that these are air-cooled engines. Sufficient air movement is required to keep engine temperatures within safe operating limits.
  • Avoid heavy traffic and congestion or extended idle periods whenever possible.
  • S&S v-twin performance engines are designed for, and happiest when running between 2750-3500 at normal highway speeds.
  • Today’s heavier bikes and taller gearing can easily push a high performance engine into a lugging condition which increases loads on engine components, causes detonation, builds excessive heat, and increases fuel consumption. If the engine does not accelerate easily when given some throttle, downshift to a lower gear.
  • S&S engines benefit from a warm-up period any time they are started, allow engine to reach operating temperature before being subjected to heavy loads or quick throttle revs.


Either petroleum or synthetic oil designed for air-cooled v-twin engines can be used during the break-in period and during normal use. If preferred, petroleum oil can be used for the break-in period, after which, the engine can be changed over to synthetic oil.


  1. Initial start up. Run engine approximately one minute at 1250- 1750 RPM. DO NOT crack throttle or subject to any loads during this period as head gaskets are susceptible to failure at this time. During this time, check to see that oil pressure is normal, that oil is returning the oil tank, and that no leaks exist.
  2. Shut off engine and thoroughly check for any leaks or other problems. Let engine cool to the touch.
  3. After engine has cooled, start up again and allow the motor to build some heat. Engine should be run no longer than three to four minutes. When the cylinders become warm/hot to the touch (approximately 150°F) shut the motor down and let it cool to room temp. Follow the same cautions as for the initial start-up, and continue to check for problems.
  4. First 50 Miles: 
    1. Street: Ride normally, do not lug the engine. Avoid high heat conditions and vary the RPM while riding. No stop and go traffic, extended idle periods, or high load or high RPM conditions. Max of 3,500 RPM or 60 MPH.
    2. Dyno: A chassis dynamometer can be used to put the first 50 miles on a new engine. See the notes and procedure below for chassis dyno break-in.
  5. 50–100 Miles: Ride normally, do not lug the engine. Avoid high heat conditions, no stop and go traffic or extended idle periods. Limited short bursts of throttle can aid in ring seating from this point forward during the break-in, but avoid continuous high speed or load conditions. Max of 4,250 RPM/70 MPH.
  6. 100–500 Miles: Avoid lugging the engine and high heat conditions. Max of 5,000 RPM. Change oil at 500 miles.
  7. 500–1,000 miles: Ride bike normally, but avoid continuous high load operation and high heat conditions.
  8. From 1,000 miles on: Break-in is complete, enjoy!


  • When running the bike on the dyno it is critical that engine temperatures are monitored, AFR is kept between 12.5–14.7 and the engine is not overheated. Fans must be used to keep the engine cool. When tuning under higher loads stop regularly and allow the engine to cool.
  • A load must be placed on the engine to properly seat the rings. Running a new engine continually with no load will result in cylinder glazing and poor ring seal. The engine should be loaded to simulate close to the weight of the bike, a load of 10–15% on a Dyno jet 250i is usually sufficient. It is not recommended to use an inertia only dyno to break-in an engine as no load can be placed on the engine.
  • Initial tuning on the engine can be completed during the initial 50 miles of dyno break-in. It is recommended the engine be run on the street for a minimum of 500 miles prior to completing tuning at full power. Monitor engine temperature during tuning to ensure the engine is not overheated.


  • Follow the same procedure outlined above for initial start-up and heat cycling the engine.
  • Run the bike for 25 miles on the dyno under varying speeds and loads while going up and down through the gears. Keep engine RPM below 3,500 RPM but do not lug the engine. The dyno must be operated so the engine runs under a load roughly equal to the power needed to move the bike down the road, this would be about 12 hp at 55 MPH. Keep engine head temperatures below 200°F at the temp sensor or surface of the head. Stop and cool the engine if needed.
  • Allow the engine to cool down to room temperature.
  • Run the bike for 25 more miles (50 miles total) under varying speeds, loads, and gears as before. Make sure there is some load on the engine. Keep engine speed below 4,250 RPM but do not lug the engine. Limited short bursts of throttle can aid in ring seating as long as the calibration/tune keeps the AFR in control. Keep engine head temperatures below 225°F at the temp sensor or surface of the head.
  • After the first 50 miles on the dyno, it is recommended the normal break-in schedule be followed under normal riding conditions on the street. See Step 5 under BREAK-IN PROCEDURE.


S&S 4" bore and smaller V-Series engines come from the factory with Champion RN12YC 14mm long reach spark plugs (S&S PN 55-1321). 4-1⁄8" bore engines come from the factory with Champion RA8HC 12mm spark plugs (S&S PN 55-1320). All spark plugs should be gapped between .038- and .042-inch. If you are not using an S&S ignition system, refer to your ignition manufacturer for any additional recommendations.


Carbureted S&S V-Series engines come from the factory with either an S&S Super StockTM or IST® ignition system installed. Fuel injected engines are equipped with an S&S VFI module.
S&S Super Stock ignition modules are factory programmed for the specific engine they are intended for. In addition the module is installed and timed to S&S specified timing. Changing the timing or removing the Super Stock ignition may void your warranty.
S&S IST ignition systems employ a knock sensor to automatically optimize ignition timing and protect your engine from damage. Removing the IST ignition may void your warranty.
Ignition timing in S&S fuel injected engines, is controlled by the S&S VFI module. The calibration file supplied by S&S for the particular engine contains ignition timing curves. If the ignition curve is modified or if another fuel injection module is used, the engine warranty may be voided.
If you choose to install another ignition system, make sure that the total ignition advance is set according to the specifications in this chart.
If the ignition system has a rev limiter, make sure it is set no higher than 6200 rpm..

EngineTotal Advance, VOES Grounded (deg BTDC)*Max Advance, Wide Open Throttle (WOT)RPM Max Advance @ WOT

If you choose to install another EFI module on a fuel injected V124 engine, the following ignition table should be used as a guide for ignition advance under various conditions

EFI Ignition Table - S&S V124, 10.8:1 CR, 640 Cam


  1. S&S Super E & G carburetors have a mixture enrichment/fast idle lever used to aide in cold starts and help during the warm-up period. Do not ride the motorcycle with the lever engaged.
  2. Turn the fuel supply valve on, wait a moment to make sure the carburetor bowl is full, and twist the throttle twice to prime the carburetor—starting in extremely cold weather may require additional priming.
  3. Pull the fast idle lever up, turn on the ignition and press the start button or kick the engine through.
  4. If the engine does not start after several kicks or five seconds of cranking, shut the ignition off for 15 seconds to let the starter cool.
  5. Open the throttle slightly and press the starter button or kick the engine through again. It may be necessary to re-prime the engine.
    If the engine kicks back, the throttle may be opened too far.
  6. Once the engine is running, use the fast idle lever to maintain the proper engine speed required during warm-up.
  7. When the engine has warmed up enough to idle without the enrichment system, disengage the fast idle lever. The fast idle lever is not required to restart a hot engine.


  1. Start the motorcycle up as outlined above.
  2. The IST ignition comes with a general ignition map that will allow the engine to be started and run. Within 3 to 5 hours of operation the IST module will optimize this map for your engine, based on data from the knock sensor and other sensors.
  3. Ride the motorcycle as you would normally, being sure to include hills, highway speeds (for at least 20 minutes at a time) and around town. Be sure to use the throttle in as many settings as possible— without going past the suggested break-in procedures!
  4. Once the engine is completely broken in, the IST will be tuned to optimize the engine’s performance.
  5. Do not run the engine on a dyno until the IST has had time to tune itself to your engine.


  1. Turn the ignition and kill switches on. Listen for the fuel pump as it pressurizes.
  2. Do not twist the throttle open to prime the system.
  3. Press the starter button and let engine crank over—do not twist the throttle. If the engine is extremely hard to start—hot or cold—contact the S&S® Tech Line or visit for the location of the closest VFI Tuning Center.


  1. Verify carburetor is set to stock settings:
    1. Idle mixture screw, 11/4 turns from lightly seated.
    2. Idle speed screw, 1⁄2 turn clockwise from engagement point.
    3. Accelerator adjustment screw, two turns counter-clockwise from seated.
  2. Start bike, bring to operating temperature.
  3. Set idle speed adjusting screw, clockwise to increase RPM, counter-clockwise to decrease RPM. Idle RPM range should be 950 to 1050 RPMs.
  4. Adjust idle mixture by turning idle mixture screw slowly clockwise until the engine runs poorly. Note position. Slowly turn the screw counter-clockwise until it starts to stumble. Note position. Set the idle mixture screw halfway between the positions, or at the strongest idle. Inconsistent idle may indicate a manifold leak.
  5. With engine idling, turn accelerator adjustment screw clockwise until it lightly seats. Snap throttle open—engine should stumble. Turn screw counter-clockwise 1/4 or 1⁄2 of a turn at a time, until engine responds to throttle twist with smooth, quick response.
  6. Ride motorcycle in various RPM ranges, and then try to maintain a consistent 40- to 50-MPH. If the engine has a flat spot, or is popping/sneezing in the air cleaner, it can indicate a lean condition. If you notice stumbling or sputtering, it can indicate a rich condition.
  7. Low RPM operation is controlled by the intermediate jet (#11 on following page). If sneezing or popping is experienced below approximately 3000 RPMs the intermediate jet must be replaced with a larger sized (richer) jet. If the engine does not run smoothly at low speeds, fouls plugs, blows black smoke or gets bad gas mileage a smaller (leaner) intermediate jet needs to be installed. Always readjust the idle mixture (#2) and idle speed (#1) screws after making a jet change.
  8. To test the main jet, do a roll-on from 50-MPH to 70-MPH in 3rd gear. If the engine backfires or breaks up in the carb, increase the main jet size .004". If the engine is flat or will not accelerate, decrease the main jet by .004".
  9. Since 2004 S&S shorty carbs have been fitted with an adjustable main jet air bleed (#13). Changing this jet to a larger size will delay the signal to the main jet, therefore aiding with high speed tuning as described in step 8. This also aides with tuning an engine that is fitted with an exhaust system that is not intended for high performance. The air bleed uses main jets, the stock size is 40. If it needs to be changed the range is normally 50 to 60.
  10. NOTE: Drag or straight pipes, especially large diameter or long designs, can prevent you from obtaining optimum carburetor performance.
  11. If the S&S teardrop air cleaner is being replaced with an aftermarket air cleaner, be sure to remove the auxiliary bowl vent screw (#14). Never use a velocity stack on a street driven motorcycle! Poor throttle response will be experienced.
  12. Always be sure to attach the hose to the overflow tube fitting (#6) and route it toward the back of the engine.

Approximate Jetting For S&S® Super E & G Carburetors
Displacement883cc74 – 88ci96 – 107ci111 – 124ci
Intermediate Jet.265 – .028.0295.031.031
Main Jet.
These jetting recommendations are a starting point only. Re-jet carb for best performance.