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T124 Engines for 1999-'06 Big Twins

Now with chrome gearcover and tappet covers!

S&S® T124 engines for carbureted and fuel injected models come standard with the distinctive teardrop air cleaner. S&S T124 performance motorcycle engine

S&S offers a truly complete 124" engine to replace the stock carbureted engines from 1999-'06 or fuel injected 1999-'05 engines. S&S T124 engines are available in silver powe rcoat, wrinkle black powder coat, and polished finishes. Match the original engine in your bike or go for a custom look.

Fitment Considerations

Complete S&S T124 engines are designed to replace the existing Harley-Davidson® Twin Cam 88® engine in a stock chassis, making it easy to get the performance you want from your late model motorcycle. Take the stock engine out and put an S&S engine in. It's that simple.

Due to changes in S&S crankcase design, installation of an S&S T124 engine in 1999-2005 Dyna™ models requires oil line installation kit #31-0424. This kit contains a special transmission top cover and oil lines for Dyna models. For
installation in 2000-'06 FLT models the stock transmission top cover may be used, but oil line installation kit #31-0425 is required.

Engines with internal counter balancers are not available from S&S to replace Harley-Davidson® Twin Cam 88B™ engines. Complete engines are also not available for 2006 Dyna™ models or any 2007 or later models. For these applications we recommend our 124" Hot Set Up Kit®.

S&S® T124 Engine Specifications

Chassis Style Bore Stroke Displacement Camshaft Piston Type Compression Ratio
1999-'06 * 4 1⁄8" 4 5⁄8" 124" S&S 640GP S&S Forged 10.8:1
* For installation in stock 1999-'06 Harley-Davidson® chassis only except 2006 Dyna™ models. Counter balanced version unavailable.
Fuel injected engines include S&S Variable Fuel Injection (VFI) system with single bore induction and teardrop air cleaner. S&S tuned induction must be purchased separately as an accessory.

Carbureted Engines

S&S T124 Performance Engine with tuned induction system
S&S T124 engine shown with polished finish and optional chrome single bore tuned induction system. All engines come standard with a teardrop air cleaner. Tuned induction system must be purchased separately. Blue filters are a further option.

Engines for 1999-'06 carbureted models come with the S&S Super G carburetor with the slotted Slasher™ air cleaner cover for good looks and improved performance. Carbureted S&S T124 engines include the S&S Intelligent Spark Technology (IST®) ignition system. In addition to the knock sensing ignition control, the IST Guardian "break in rev limit" feature protects the new engine from premature failure with a lower rev limit during break in. IST equipped engines are covered by an extended two year warranty because we are confident that the IST ignition will protect the engine from damage. Available for 1999-'06 models.


Fuel Injected Engines

Complete fuel injected T124 engines for 1999-'06 models come with the S&S Variable Fuel Injection (VFI) Module and S&S single bore induction system with a teardrop air cleaner. Engines can easily be upgraded to S&S single bore tuned induction with a simple bolt-on induction kit. The VFI system included with each fuel injected engine, comes with closed loop sensors and the complete S&S ProTune II software package. Delphi® style systems also include knock sensors and break-in rev limiting to protect your engine from damage. Base maps for T124 engines with the most common exhaust systems are available on the software CD and from the S&S website. However, it is recommended that the VFI System be fine tuned at an S&S VFI Tuning Center. Since we have added the S&S Closed Loop Sensor Kit to all VFI equipped engines, tuning is much easier and the amount of dyno time required to fine tune the engine is greatly reduced.

If a different exhaust or intake system is used, the fuel maps must be modified. It is highly recommended that this tuning be done by a certified S&S VFI tuning center. Visit our dealer locator to locate your nearest certified S&S VFI tuning center or to download maps for the S&S VFI system here.


Complete Carbureted S&S® T124 Engines for Stock 1999-'06 Chassis

Chassis Style Ignition Warranty
Silver Black Finish Polished
Diamond Cut
Diamond Cut
-Full Polished
1999-'03 Carb S&S IST* 2 Years 106-4328 31-9895 31-9896 106-0830 106-0828  n/a
2004-'06 Carb 310-0200 310-0201 310-0202 310-0207 310-0203 310-0205
 *Engines with S&S IST ignition may be used in 1999-'06 chassis.


Complete Fuel Injected S&S® T124 Engines for Stock 1999-'05 Chassis

Fuel Injection Style
Silver Black Finish Polished Finish Full
2002-'03 2 Years 106-4323 106-0402 106-0403 106-0800
2004-'05 310-0221 310-0216 310-0217 310-0219
Includes S&S VFI module. All VFI equipped engines include single bore induction with S&S teardrop air cleaner. Tuned induction can be purchased separately as an accessory.

Not legal for sale or use on EPA or CA pollution controlled vehicles.