Piston Kit - 4.250" +0.005" - 11.7:1 CR - 128" Big Bore - 114"/117" M8
Features
- Valve pockets are designed to accept up to +4.00 mm oversized intake and exhaust valves
- Type 3 hard-anodized crown offers corrosion resistance for alcohol-added fuels
- Type 3 hard-anodized top ring groove eliminates micro-welding of ring to the groove and gives a hard-flat surface for ring to rotate on
- OE-style round wire locks are easily installed
- Heavy-duty wrist pins with true 0.9270” diameter to fit rods correctly
- Line2Line AST skirt coating starts out with a near-zero wall clearance and through the break-in period hones the cylinders to produce the correct oil wedge, keeping the piston square to the cylinder for best ring seal and quiet operation
- Kit includes pistons, rings, pins and locks
- Requires 4.250" bore cylinder sold separately.
Specs
| Units | Kit |
| Compression Ratio | 11.7:1 |
| Riding Style | Street |
| Displacement | 128" |
| Stroke Length | 4.500" |
| Model | Super Duty |
| Bore - Oversize | +0,005" |
| Bore Size | 4.250" |
| Piston Material | 4032 Aluminum Alloy |
| Type | Big Bore |
| Piston Head Shape | Domed |
| Product Name | Piston Kit |
| Style | Forged |
| Year | Make | Model |
|---|---|---|
| 2017 | Harley-Davidson | FLHRXS Road King Special |
| 2017 | Harley-Davidson | FLHTCU Electra Glide Ultra Classic |
| 2017 | Harley-Davidson | FLHTKSE CVO Limited |
| 2017 | Harley-Davidson | FLHXS Street Glide Special |
| 2017 | Harley-Davidson | FLHXSE CVO Street Glide |
| 2017 | Harley-Davidson | FLTRX Road Glide |
| 2017 | Harley-Davidson | FLTRXS Road Glide Special |
| 2018 | Harley-Davidson | FLFBS Fat Boy 114 |
| 2018 | Harley-Davidson | FLHCS Heritage Classic 114 |
| 2018 | Harley-Davidson | FLHRXS Road King Special |
| 2018 | Harley-Davidson | FLHTCU Electra Glide Ultra Classic |
| 2018 | Harley-Davidson | FLHTKSE CVO Limited |
| 2018 | Harley-Davidson | FLHXS Street Glide Special |
| 2018 | Harley-Davidson | FLHXSE CVO Street Glide |
| 2018 | Harley-Davidson | FLTRX Road Glide |
| 2018 | Harley-Davidson | FLTRXS Road Glide Special |
| 2018 | Harley-Davidson | FLTRXSE CVO Road Glide |
| 2018 | Harley-Davidson | FXBRS Breakout 114 |
| 2018 | Harley-Davidson | FXFBS Fat Bob 114 |
| 2019 | Harley-Davidson | FLFBS Fat Boy 114 |
| 2019 | Harley-Davidson | FLHCS Heritage Classic 114 |
| 2019 | Harley-Davidson | FLHRXS Road King Special |
| 2019 | Harley-Davidson | FLHTCU Electra Glide Ultra Classic |
| 2019 | Harley-Davidson | FLHTKSE CVO Limited |
| 2019 | Harley-Davidson | FLHXS Street Glide Special |
| 2019 | Harley-Davidson | FLHXSE CVO Street Glide |
| 2019 | Harley-Davidson | FLTRX Road Glide |
| 2019 | Harley-Davidson | FLTRXS Road Glide Special |
| 2019 | Harley-Davidson | FLTRXSE CVO Road Glide |
| 2019 | Harley-Davidson | FXBRS Breakout 114 |
| 2019 | Harley-Davidson | FXDRS FXDR 114 |
| 2019 | Harley-Davidson | FXFBS Fat Bob 114 |
| 2020 | Harley-Davidson | FLFBS Fat Boy 114 |
| 2020 | Harley-Davidson | FLHCS Heritage Classic 114 |
| 2020 | Harley-Davidson | FLHRXS Road King Special |
| 2020 | Harley-Davidson | FLHTKSE CVO Limited |
| 2020 | Harley-Davidson | FLHXS Street Glide Special |
| 2020 | Harley-Davidson | FLHXSE CVO Street Glide |
| 2020 | Harley-Davidson | FLTRX Road Glide |
| 2020 | Harley-Davidson | FLTRXS Road Glide Special |
| 2020 | Harley-Davidson | FLTRXSE CVO Road Glide |
| 2020 | Harley-Davidson | FXBRS Breakout 114 |
| 2020 | Harley-Davidson | FXDRS FXDR 114 |
| 2020 | Harley-Davidson | FXFBS Fat Bob 114 |
| 2021 | Harley-Davidson | FLFBS Fat Boy 114 |
| 2021 | Harley-Davidson | FLHCS Heritage Classic 114 |
| 2021 | Harley-Davidson | FLHRXS Road King Special |
| 2021 | Harley-Davidson | FLHTKSE CVO Limited |
| 2021 | Harley-Davidson | FLHXS Street Glide Special |
| 2021 | Harley-Davidson | FLHXSE CVO Street Glide |
| 2021 | Harley-Davidson | FLTRX Road Glide |
| 2021 | Harley-Davidson | FLTRXS Road Glide Special |
| 2021 | Harley-Davidson | FLTRXSE CVO Road Glide |
| 2021 | Harley-Davidson | FXFBS Fat Bob 114 |
| 2022 | Harley-Davidson | FLFBS Fat Boy 114 |
| 2022 | Harley-Davidson | FLHCS Heritage Classic 114 |
| 2022 | Harley-Davidson | FLHRXS Road King Special |
| 2022 | Harley-Davidson | FLHXS Street Glide Special |
| 2022 | Harley-Davidson | FLHXSE CVO Street Glide |
| 2022 | Harley-Davidson | FLTRX Road Glide |
| 2022 | Harley-Davidson | FLTRXS Road Glide Special |
| 2022 | Harley-Davidson | FLTRXSE CVO Road Glide |
| 2022 | Harley-Davidson | FXFBS Fat Bob 114 |
| 2023 | Harley-Davidson | FLFBS Fat Boy 114 |
| 2023 | Harley-Davidson | FLHCS Heritage Classic 114 |
| 2023 | Harley-Davidson | FLHRXS Road King Special |
| 2023 | Harley-Davidson | FLHXS Street Glide Special |
| 2023 | Harley-Davidson | FLHXSE CVO Street Glide |
| 2023 | Harley-Davidson | FLTRX Road Glide |
| 2023 | Harley-Davidson | FLTRXS Road Glide Special |
| 2023 | Harley-Davidson | FLTRXSE CVO Road Glide |
| 2023 | Harley-Davidson | FXFBS Fat Bob 114 |
| 2024 | Harley-Davidson | FLFBS Fat Boy 114 |
| 2024 | Harley-Davidson | FLHCS Heritage Classic 114 |
| 2024 | Harley-Davidson | FLHRXS Road King Special |
| 2024 | Harley-Davidson | FLHXSE CVO Street Glide |
| 2024 | Harley-Davidson | FLTRX Road Glide |
| 2024 | Harley-Davidson | FLTRXSE CVO Road Glide |
Fitment details provided by supplier.
Product Videos
Custom Field
Type Big Bore