S&S 106 Stroker Flywheel For Harley Twin Cam B Features Installation of the kit does not require any special machining, other than fitting the pistons S&S Cycle standard stroker piston kit 420-123 also available in all standard oversizes Stock 88 cylinders can be bored from 3-3/4 bore to 3-7/8 to accommodate the S&S Cycle pistons, or a pre-fit S&S Cycle cylinder and piston kit may be installed Engines with factory 95 kits require piston fitting only - stock or S&S Cycle cylinder heads can be used Fuel injected engines will require recalibration of the fuel injection system - the S&S Cycle VFI modules and closed loop sensor kits are highly recommended For balanced motors Without bearing race