89XLSS Flywheel, Pistons, & Cams Kit - Bored And Stroked Sportster

89-Inch S&S; Package

1. The 89XLSS Hot Set-Up Kit included flywheels with rods and mainshafts, pistons, cylinders, heads, cams, adjustable pushrods, Super G carburetor, manifold, and air-cleaner assembly, pinion gear, and oil-pump drive gear. Also shown are roller rockers and rocker boxes. Not shown are gaskets, hardware, pushrod-cover keepers, and the HL2T kit that limits the lifter's travel and prevents high-rpm lifter collapse.

2. The 4-51/416-inch-stroke flywheels come fully assembled with mainshafts and connecting rods installed at the factory. Rods measure 7.113 inches compared to the stock 6.926-inch length. Flywheel assemblies come dynamically balanced from the S&S; factory. Also included are the pinion gear and oil-pump drive gear.

3. The pinion shaft supplied with this kit is the stronger, splined '86-'87 style. If using the crank assembly in '88-'03 models, the pinion and oil-pump drive gears must be replaced with the earlier-style gears. The mainshaft utilizes the '87-and-up-style steel-caged roller main bearing and race.

4. Here are two views of the 3-5/8-inch-bore Sidewinder cylinders. These barrels measure in at 5.087 inches, 0.437 inches taller than the 4.65-inch stock cylinders. Installing these requires that the crankcase cylinder spigot holes be bored to accept the larger cylinders. You also get an extra cooling fin with the taller cylinders.

5. These forged pistons were designed to work with S&S;'s contoured combustion chamber. Their shape increases compression ratio (over a flat-top piston) while contributing to a larger squish area for better combustion. Static compression ratio was determined to be 10.2:1. A benefit to the taller cylinders in the kit is the ability to run pistons with longer skirts than are seen in many stroker applications. This helps with better piston stability in the bore.

6. The Super Stock cylinder heads are precision CNC-machined from heat-treated aircraft-quality aluminum castings and come with valves and valvesprings installed.

7. The intake valves measure 2 inches in diameter, while the exhaust valves are 1.605 inches. The larger, more open combustion chamber presents less resistance to airflow around the valves. This combustion chamber-combined with the specially designed piston dome-leads to a controlled turbulence in the combustion chamber that improves flame travel for a more efficient burn and reduced detonation.

8. Special "cast to shape" intake ports with a directional fin provide improved airflow throughout the rpm range.

9. The exhaust ports come with studs installed and were designed to speed up exhaust gasses, leading to more efficient combustion.

10. Keeping the valves in check is accomplished with 0.640-max-lift triple valvesprings, featuring drilled-steel top collars that are lighter and aid in cooling.

11. These S&S; rocker boxes consist of two pieces for a simple installation instead of the stock three-piece system. These polished die-cast rocker covers include rocker shaft supports and Viton O-rings for leak-free operation. These can be used whether the engine vents through the crankcase or the cylinder heads. The cast rocker boxes use an exclusive one-way valve that is built into the rocker-cover gasket to control oil blow-by in head-breathing engines.

12. Forged-steel roller rocker arms were designed for superior strength and to prevent failure in stress areas found in non-roller rockers. S&S; roller rockers are forged from 4140 steel, heat-treated, and shot-peened for additional strength and protection from fatigue. The rockers also utilize 31/44-inch-long bronze bushings.

13. Adjustable pushrods are a necessity when building any high-performance engine. S&S; chrome-moly pushrods are designed to remain rigid and provide positive valve actuation at all engine speeds. Pushrod flex costs horsepower by preventing the valves from following the cam profile. This problem is most common in high-performance applications with heavier-than-stock valvesprings.

14. S&S; 555 cams will be used to get the pushrods and valves moving. The 555 cams (Andrews V9) work well in high-compression, big-bore motors.

Grind 555 (V9) Timing Duration Max Lift
Intake 33/53 266 0.555
Exhaust 53/33 266 0.555
Timing listed for .053-inch lift.

15. The motor will breathe through a Super G carb and manifold. The manifold was designed specifically for the increased height of the big-bore cylinders.

16. Lastly, the iconic teardrop air-cleaner cover will protect the air cleaner while increasing airflow into the carburetor.

In last month's issue we showed you how we modified our '86 Sportster frame to accommodate an S&S; Sidewinder/Stroker kit fitted into H-D Sportster cases. Due to the longer stroke, the cylinders are taller than stock, necessitating frame clearance in the backbone and seat post. In addition, the stock four-speed H-D cases had to be bored in the cylinder spigot area to hold the larger-sized bore cylinders. We'll be covering the required engine-case splitting in an upcoming article.

The 89XLSS Sidewinder/Stroker Hot Set-Up Kit (part No. 90-0353; $3,809.95) takes any 883 or 1200 Evo Sportster to a tire-shredding 89ci (~1,458cc). Included in the kit are assembled flywheels with connecting rods and mainshafts, pistons, rings, Sidewinder cylinders, Super Stock cylinder heads, cams, adjustable pushrods, HL2T kit, Super E or G carburetor and manifold, head bolts, hardware, top-end and base gaskets, pushrod-cover keepers, and front and top motor mounts. We are also installing S&S; roller rocker arms (part No. 90-4065; $474.95) and polished die-cast rocker boxes (part No. 90-4090; $474.95).

S&S; offers many different options for four- and five-speed H-D-based Sportster motors going back to Ironhead Sportsters, from stock displacements to a 103ci monster. All parts in these kits may be purchased separately to allow you to get exactly what you need or want. Next month we'll show you the assembly of the bottom end of the motor.