S&S Cycle Flywheel Weights

S&S Cycle Flywheel Weights for Precision Engine Balancing

Flywheel balance is one of the least glamorous but most important details in a V-twin engine build. When the rotating assembly is out of balance, the result can be vibration, premature bearing wear and a rough-running motor, no matter how good the cylinders, cams and heads are. S&S Cycle has spent decades building performance parts for Harley-Davidson® and other V-twin engines, and its flywheel weights and balancing components reflect that shop-floor experience.

The S&S Bob Weight Assembly

The centerpiece of S&S Cycle's offering in this category is the bob weight assembly. It is a 1000 gram bob weight assembly made for S&S flywheel balancing and manufactured in the USA. A bob weight simulates the combined rotating weight of the connecting rod and piston assembly. With it bolted to the flywheel, a builder can find the heavy spot and determine how much weight must be added or removed so the assembly rotates in true balance.

S&S documents the process in its instruction sheets. The flywheel assembly is placed on a balance stand and allowed to rotate. When the flywheel no longer rotates on its own, it is in balance. Because heavy bob weights can be difficult to work with, S&S also describes removing weights from the bob weight, balancing the flywheel to that lighter figure, and then replacing the weights, a practical detail that shows the tooling was designed around real engine-building work.

Part of a Complete Balancing System

S&S's bob weight is designed to work with its flywheel balancing kits. The master kit is described as letting the average shop rebalance stock and S&S flywheels accurately and quickly, whether the job is a stock rebuild or a performance upgrade with aftermarket parts. Kits are matched to the engine: separate configurations exist for three-piece and five-piece cranks, along with adapter sleeves for Sportster® applications and an assortment of shims in graduated weights. Those shims, from a few grams up to 100 grams, allow fine adjustment of the counterweight until the assembly is dialed in.

One caution worth noting is that these balancing kits are not intended for Harley-Davidson Twin Cam 88® engines, 2000-up Sportster models, or any flywheel assemblies that use pressed-in crankpins. Confirm your engine's crank design before choosing balancing components.

Who Benefits from S&S Flywheel Weights

• Engine builders and shops rebalancing stock or S&S flywheels during rebuilds.
• Performance enthusiasts who change piston or rod weight and need to re-establish proper balance.
• Restoration and custom builders working with two-piece mainshaft and flywheel assemblies who want smoother, more reliable running.

Explore More

S&S Cycle's reputation was built on high-performance parts for V-twin motorcycles after its founding in 1958, and balancing tools like these support that same goal of dependable, repeatable engine performance. To see the full range of products from the manufacturer, visit the S&S Cycle brand page. If you want to compare options from other manufacturers, browse the complete Flywheel Weights category.