S&S Cycle 2007+ BT 3.937in x 4-3/8in Piston Set

These big bore pistons work with the stock 4-3/8" stroke flywheels to convert any 2007-'16 HD® big twin engine from 96" or 103" to 107" displacement with 10.4:1 compression with stock heads. Stock cylinders may be bored to accomodate larger pistons, but we recommend S&S 3.927" bore cylinders which feature high strength alloyed cast iron liners. Pistons are compatible with stock rods with tapered wristpin ends. S&S® 3.927" bore pistons are machined to such close tolerances that it is not necessary to measure the piston. Just bore cylinders to nominal diameter +/- 0.0005" for correct clearance. Additionally, the low friction coating on the piston skirt makes taking measurements very difficult. 3.937" standard bore.

Upgrade your Harley Davidson big twin engine with the S&S Cycle 2007+ BT 3.937-inch x 4-3/8-inch piston set, designed to increase displacement from 96" or 103" to a powerful 107". These high-performance pistons are engineered to work with stock 4-3/8" stroke flywheels and are compatible with stock rods featuring tapered wristpin ends, ensuring a reliable upgrade for your motorcycle. The pistons feature a compression ratio of 10.4:1, providing a balance of power and efficiency suitable for many riding styles. Stock cylinders can be bored to accommodate these larger pistons, but for optimal performance and durability, S&S recommends using their 3.927" bore cylinders, which incorporate high-strength alloyed cast iron liners for durability under high stress. The pistons are machined to precise tolerances, eliminating the need for measurement, and are designed to bore cylinders to a nominal diameter with minimal clearance, simplifying installation. The low friction coating on the piston skirt reduces wear and enhances longevity, making these pistons ideal for performance-oriented rebuilds. Please note that these pistons are not carb approved and require carb acknowledgment prior to installation. As a versatile upgrade, they are compatible with several Harley Davidson models including the FLHX Street Glide, FXDF Fat Bob, and others from 2007 through 2009. Built by S&S Cycle, a trusted name in powersports performance, these pistons are a key component to achieving substantial engine displacement increases with reliable performance and quality craftsmanship.

Features:

• Designed for 2007+ Harley Davidson big twin engines to increase displacement to 107"

• Compatible with stock 4-3/8" stroke flywheels and stock rods with tapered wristpin ends

• Includes a compression ratio of 10.4:1 for balanced power and efficiency

• Machined to close tolerances; no measurement needed during installation

• Low friction coating on piston skirts reduces wear and extends engine life

• Works with stock cylinders or S&S 3.927" bore cylinders featuring high-strength alloyed cast iron liners

• Bore cylinders to nominal diameter for proper clearance, simplifying assembly

• Part of high-performance powersports components by S&S Cycle

• Fits multiple Harley Davidson models from 2007 to 2009, including Street Glide, Fat Bob, and Cross Bones

Fitment:
Harley Davidson FLHR Road King Base 2007
Harley Davidson FLHR Road King Base 2008
Harley Davidson FLHR Road King Base 2009
Harley Davidson FLHR Road King Base 2010
Harley Davidson FLHR Road King Base 2011
Harley Davidson FLHR Road King Base 2012
Harley Davidson FLHR Road King Base 2013
Harley Davidson FLHR Road King Base 2014
Harley Davidson FLHR Road King Base 2015
Harley Davidson FLHR Road King Base 2016
Harley Davidson FLHRC Road King Classic Base 2008
Harley Davidson FLHRC Road King Classic Base 2009
Harley Davidson FLHRC Road King Classic Base 2010
Harley Davidson FLHRC Road King Classic Base 2011
Harley Davidson FLHRC Road King Classic Base 2012
Harley Davidson FLHRC Road King Classic Base 2013
Harley Davidson FLHRS Road King Custom Base 2007
Harley Davidson FLHT Electra Glide Standard Base 2007
Harley Davidson FLHT Electra Glide Standard Base 2008
Harley Davidson FLHT Electra Glide Standard Base 2009
Harley Davidson FLHTC Electra Glide Classic Base 2009
Harley Davidson FLHTC Electra Glide Classic Base 2010
Harley Davidson FLHTC Electra Glide Classic Base 2011
Harley Davidson FLHTC Electra Glide Classic Base 2012
Harley Davidson FLHTC Electra Glide Classic Base 2013
Harley Davidson FLHTCU Electra Glide Ultra Classic Base 2009
Harley Davidson FLHTCU Electra Glide Ultra Classic Base 2010
Harley Davidson FLHTCU Electra Glide Ultra Classic Base 2011
Harley Davidson FLHTCU Electra Glide Ultra Classic Base 2012
Harley Davidson FLHTCU Electra Glide Ultra Classic Base 2013
Harley Davidson FLHTCU Electra Glide Ultra Classic Base 2014
Harley Davidson FLHTCU Electra Glide Ultra Classic Base 2015
Harley Davidson FLHTCU Electra Glide Ultra Classic Base 2016
Harley Davidson FLHTCUL Electra Glide Ultra Classic Low Base 2015
Harley Davidson FLHTCUL Electra Glide Ultra Classic Low Base 2016
Harley Davidson FLHTCUSE4 CVO Ultra Classic Electra Glide Base 2009
Harley Davidson FLHTCUSE5 CVO Ultra Classic Electra Glide Base 2010
Harley Davidson FLHTCUTG Tri Glide Ultra Base 2009
Harley Davidson FLHTCUTG Tri Glide Ultra Base 2011
Harley Davidson FLHTCUTG Tri Glide Ultra Base 2012
Harley Davidson FLHTCUTG Tri Glide Ultra Base 2013
Harley Davidson FLHTCUTG Tri Glide Ultra Base 2014
Harley Davidson FLHTCUTG Tri Glide Ultra Classic Base 2009
Harley Davidson FLHTCUTG Tri Glide Ultra Classic Base 2010
Harley Davidson FLHTCUTG Tri Glide Ultra Classic Base 2011
Harley Davidson FLHTCUTG Tri Glide Ultra Classic Base 2012
Harley Davidson FLHTCUTG Tri Glide Ultra Classic Base 2013
Harley Davidson FLHTK Electra Glide Ultra Limited Base 2010
Harley Davidson FLHTK Electra Glide Ultra Limited Base 2011
Harley Davidson FLHTK Electra Glide Ultra Limited Base 2012
Harley Davidson FLHTK Electra Glide Ultra Limited Base 2013
Harley Davidson FLHTK Electra Glide Ultra Limited Base 2014
Harley Davidson FLHTKSE CVO Limited Base 2015
Harley Davidson FLHTKSE CVO Limited Base 2016
Harley Davidson FLHTKSE CVO Limited Base 2017
Harley Davidson FLHX Street Glide Base 2007
Harley Davidson FLHX Street Glide Base 2008
Harley Davidson FLHX Street Glide Base 2009
Harley Davidson FLHX Street Glide Base 2010
Harley Davidson FLHX Street Glide Base 2011
Harley Davidson FLHX Street Glide Base 2012
Harley Davidson FLHX Street Glide Base 2013
Harley Davidson FLHX Street Glide Base 2014
Harley Davidson FLHX Street Glide Base 2015
Harley Davidson FLHX Street Glide Base 2016
Harley Davidson FLHXS Street Glide Special Base 2014
Harley Davidson FLHXS Street Glide Special Base 2016
Harley Davidson FLHXSE CVO Street Glide Base 2015
Harley Davidson FLHXSE CVO Street Glide Base 2016
Harley Davidson FLHXSE CVO Street Glide Base 2017
Harley Davidson FLHXSE2 CVO Street Glide Base 2011
Harley Davidson FLHXSE3 CVO Street Glide Base 2012
Harley Davidson FLRT Freewheeler Base 2015
Harley Davidson FLRT Freewheeler Base 2016
Harley Davidson FLS Softail Slim Base 2012
Harley Davidson FLS Softail Slim Base 2013
Harley Davidson FLS Softail Slim Base 2014
Harley Davidson FLS Softail Slim Base 2015
Harley Davidson FLS Softail Slim Base 2016
Harley Davidson FLS Softail Slim Base 2017
Harley Davidson FLSS Softail Slim S Base 2016
Harley Davidson FLSS Softail Slim S Base 2017
Harley Davidson FLSTC Heritage Softail Classic Base 2007
Harley Davidson FLSTC Heritage Softail Classic Base 2008
Harley Davidson FLSTC Heritage Softail Classic Base 2009
Harley Davidson FLSTC Heritage Softail Classic Base 2010
Harley Davidson FLSTC Heritage Softail Classic Base 2011
Harley Davidson FLSTC Heritage Softail Classic Base 2012
Harley Davidson FLSTC Heritage Softail Classic Base 2013
Harley Davidson FLSTC Heritage Softail Classic Base 2014
Harley Davidson FLSTC Heritage Softail Classic Base 2015
Harley Davidson FLSTC Heritage Softail Classic Base 2016
Harley Davidson FLSTC Heritage Softail Classic Base 2017
Harley Davidson FLSTF Fat Boy Base 2007
Harley Davidson FLSTF Fat Boy Base 2008
Harley Davidson FLSTF Fat Boy Base 2009
Harley Davidson FLSTF Fat Boy Base 2010
Harley Davidson FLSTF Fat Boy Base 2011
Harley Davidson FLSTF Fat Boy Base 2012
Harley Davidson FLSTF Fat Boy Base 2013
Harley Davidson FLSTF Fat Boy Base 2014
Harley Davidson FLSTF Fat Boy Base 2015
Harley Davidson FLSTF Fat Boy Base 2016
Harley Davidson FLSTF Fat Boy Base 2017
Harley Davidson FLSTFB Fat Boy Lo Base 2010
Harley Davidson FLSTFB Fat Boy Lo Base 2011
Harley Davidson FLSTFB Fat Boy Lo Base 2012
Harley Davidson FLSTFB Fat Boy Lo Base 2013
Harley Davidson FLSTFB Fat Boy Lo Base 2014
Harley Davidson FLSTFB Fat Boy Lo Base 2015
Harley Davidson FLSTFB Fat Boy Lo Base 2016
Harley Davidson FLSTFBS Fat Boy S Base 2016
Harley Davidson FLSTFBS Fat Boy S Base 2017
Harley Davidson FLSTN Softail Deluxe Base 2007
Harley Davidson FLSTN Softail Deluxe Base 2008
Harley Davidson FLSTN Softail Deluxe Base 2009
Harley Davidson FLSTN Softail Deluxe Base 2010
Harley Davidson FLSTN Softail Deluxe Base 2011
Harley Davidson FLSTN Softail Deluxe Base 2012
Harley Davidson FLSTN Softail Deluxe Base 2013
Harley Davidson FLSTN Softail Deluxe Base 2014
Harley Davidson FLSTN Softail Deluxe Base 2017
Harley Davidson FLSTNSE CVO Softail Deluxe Base 2014
Harley Davidson FLSTNSE CVO Softail Deluxe Base 2015
Harley Davidson FLSTSB Cross Bones Base 2008
Harley Davidson FLSTSB Cross Bones Base 2009
Harley Davidson FLSTSB Cross Bones Base 2010
Harley Davidson FLSTSB Cross Bones Base 2011
Harley Davidson FLTR Road Glide Base 2007
Harley Davidson FLTR Road Glide Base 2008
Harley Davidson FLTR Road Glide Base 2009
Harley Davidson FLTRSE3 CVO Road Glide Base 2009
Harley Davidson FLTRU Road Glide Ultra Base 2011
Harley Davidson FLTRU Road Glide Ultra Base 2012
Harley Davidson FLTRU Road Glide Ultra Base 2013
Harley Davidson FLTRU Road Glide Ultra Base 2016
Harley Davidson FLTRUSE CVO Road Glide Ultra Base 2015
Harley Davidson FLTRUSE CVO Road Glide Ultra Base 2016
Harley Davidson FLTRX Road Glide Base 2015
Harley Davidson FLTRX Road Glide Base 2016
Harley Davidson FLTRX Road Glide Custom Base 2010
Harley Davidson FLTRX Road Glide Custom Base 2011
Harley Davidson FLTRX Road Glide Custom Base 2012
Harley Davidson FLTRX Road Glide Custom Base 2013
Harley Davidson FLTRXS Road Glide Special Base 2015
Harley Davidson FLTRXS Road Glide Special Base 2016
Harley Davidson FLTRXSE CVO Road Glide Custom Base 2012
Harley Davidson FXCW Rocker Base 2008
Harley Davidson FXCW Rocker Base 2009
Harley Davidson FXCWC Rocker C Base 2008
Harley Davidson FXCWC Rocker C Base 2009
Harley Davidson FXCWC Rocker C Base 2010
Harley Davidson FXCWC Rocker C Base 2011
Harley Davidson FXD Dyna Super Glide Base 2007
Harley Davidson FXD Dyna Super Glide Base 2008
Harley Davidson FXD Dyna Super Glide Base 2009
Harley Davidson FXD Dyna Super Glide Base 2010
Harley Davidson FXDB Street Bob Base 2007
Harley Davidson FXDB Street Bob Base 2008
Harley Davidson FXDB Street Bob Base 2009
Harley Davidson FXDB Street Bob Base 2010
Harley Davidson FXDB Street Bob Base 2011
Harley Davidson FXDB Street Bob Base 2012
Harley Davidson FXDB Street Bob Base 2013
Harley Davidson FXDB Street Bob Base 2014
Harley Davidson FXDB Street Bob Base 2015
Harley Davidson FXDB Street Bob Base 2016
Harley Davidson FXDC Super Glide Custom Base 2007
Harley Davidson FXDC Super Glide Custom Base 2008
Harley Davidson FXDC Super Glide Custom Base 2009
Harley Davidson FXDC Super Glide Custom Base 2010
Harley Davidson FXDC Super Glide Custom Base 2011
Harley Davidson FXDC Super Glide Custom Base 2012
Harley Davidson FXDC Super Glide Custom Base 2013
Harley Davidson FXDC Super Glide Custom Base 2014
Harley Davidson FXDF Fat Bob Base 2008
Harley Davidson FXDF Fat Bob Base 2009
Harley Davidson FXDF Fat Bob Base 2010
Harley Davidson FXDF Fat Bob Base 2011
Harley Davidson FXDF Fat Bob Base 2012
Harley Davidson FXDF Fat Bob Base 2013
Harley Davidson FXDF Fat Bob Base 2014
Harley Davidson FXDF Fat Bob Base 2015
Harley Davidson FXDF Fat Bob Base 2016
Harley Davidson FXDF Fat Bob Base 2017
Harley Davidson FXDFSE CVO Dyna Fat Bob Base 2009
Harley Davidson FXDL Dyna Low Rider Base 2007
Harley Davidson FXDL Dyna Low Rider Base 2008
Harley Davidson FXDL Dyna Low Rider Base 2009
Harley Davidson FXDL Dyna Low Rider Base 2014
Harley Davidson FXDL Dyna Low Rider Base 2015
Harley Davidson FXDL Dyna Low Rider Base 2016
Harley Davidson FXDL Dyna Low Rider Base 2017
Harley Davidson FXDL Low Rider Base 2014
Harley Davidson FXDL Low Rider Base 2015
Harley Davidson FXDL Low Rider Base 2016
Harley Davidson FXDL Low Rider Base 2017
Harley Davidson FXDLS Low Rider S Base 2016
Harley Davidson FXDLS Low Rider S Base 2017
Harley Davidson FXDWG Dyna Wide Glide Base 2007
Harley Davidson FXDWG Dyna Wide Glide Base 2008
Harley Davidson FXDWG Dyna Wide Glide Base 2010
Harley Davidson FXDWG Dyna Wide Glide Base 2011
Harley Davidson FXDWG Dyna Wide Glide Base 2012
Harley Davidson FXDWG Dyna Wide Glide Base 2013
Harley Davidson FXDWG Dyna Wide Glide Base 2014
Harley Davidson FXDWG Dyna Wide Glide Base 2015
Harley Davidson FXDWG Dyna Wide Glide Base 2016
Harley Davidson FXDWG Dyna Wide Glide Base 2017
Harley Davidson FXS Blackline Base 2011
Harley Davidson FXS Blackline Base 2012
Harley Davidson FXS Blackline Base 2013
Harley Davidson FXSB Breakout Base 2014
Harley Davidson FXSB Breakout Base 2015
Harley Davidson FXSB Breakout Base 2016
Harley Davidson FXSB Breakout Base 2017
Harley Davidson FXSBSE CVO Breakout Base 2013
Harley Davidson FXSE CVO Pro Street Breakout Base 2016
Harley Davidson FXSE CVO Pro Street Breakout Base 2017
Harley Davidson FXST Softail Standard Base 2007
Harley Davidson FXSTB Night Train Base 2007
Harley Davidson FXSTB Night Train Base 2008
Harley Davidson FXSTB Night Train Base 2009
Harley Davidson FXSTC Softail Custom Base 2008
Harley Davidson FXSTC Softail Custom Base 2010
Harley Davidson FXSTD Softail Deuce Base 2007
Harley Davidson FXSTSSE3 CVO Softail Springer Base 2009