S&S Cycle
S&S Cycle 84-99 BT 4-1/8in Stroke Flywheel Assembly
SKU: S0GE 320-0420
Description
Part #: 320-0420
This 4-1/8" stroke 8-1/2" diameter flywheel assembly replaces the original flywheels in S&S (R) 111" V111 engines for 1984-99 HD (R) big twins. Flywheel assembly is three piece design. Pinion and sprocket shafts are forged as part of the flywheel. The only joints in the assembly are where the 1.671" diameter connecting rod crankpin is pressed into the flywheels.
Fitment
Fitment Guaranteed
Don’t gamble
on fit.
Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.
Available on iOS & Android
Specifications
| Brand | S&S Cycle |
| Part Number | S0GE 320-0420 |
Videos
Harley Performance S&S 124ci Twin Cam Dark Horse Crank
Is The Evo Sportster The Best Harley Engine Ever Made?
Why the Harley-Davidson Evo Engine is Perfect for DIY Mechanics
Is the Harley Evo really that good, Is the Twin Cam Really That Bad
Swapping Your Harley-Davidson Engine is Better than a Rebuild
3 WORST and 4 BEST HARLEY-DAVIDSON Motorcycle Engines to RIDE FOREVER
Harley Davidson Evo --- Should you buy one?
10 Harley Davidson Engines That Last Forever (According to REDDIT)
How to Install Ultima Harley Davidson Evo Motor Dyna FXD Ignition Upgrade Kit
Harley Davidson EVO vs Milwaukee Eight: THE REAL WINNER Revealed
Buy with Confidence
Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.
View Full Return Policy