Iron Stable

Harley-Davidson SOFTAIL STANDARD Big Bore Kits

Genuine HD big bore kits and aftermarket alternatives that fit the SOFTAIL STANDARD — all years. Select your year for exact fitment and pricing.

Select your year for exact fitment & prices

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Genuine Harley-Davidson (16)

Screamin' Eagle Stage II Bolt-On Power Kit

Genuine Harley-Davidson

Screamin' Eagle Stage II Bolt-On Power Kit

92500075A
Iron Pass £474.05£557.71View
3-7/8" Standard Bore Piston Kit

Genuine Harley-Davidson

3-7/8" Standard Bore Piston Kit

22144-08B
Iron Pass £323.92£381.08View
Screamin' Eagle 4-Inch Big Bore Conversion Kit

Genuine Harley-Davidson

Screamin' Eagle 4-Inch Big Bore Conversion Kit

92500039
Iron Pass £1148.32£1350.96View
Big Bore Head Gasket Kit

Genuine Harley-Davidson

Big Bore Head Gasket Kit

16101-01
Iron Pass £48.25£56.76View
Screamin' Eagle 103 Stage IV Performance Kit

Genuine Harley-Davidson

Screamin' Eagle 103 Stage IV Performance Kit

27516-08F
Iron Pass £2467.89£2903.40View
Screamin' Eagle 131CI Stage IV Performance Kit

Genuine Harley-Davidson

Screamin' Eagle 131CI Stage IV Performance Kit

92500095
Iron Pass £3212.39£3779.28View
Screamin' Eagle MVA CNC Ported Cylinder Heads

Genuine Harley-Davidson

Screamin' Eagle MVA CNC Ported Cylinder Heads

16925-11
Iron Pass £1422.25£1673.23View
Flat-Top Cast Pistons, 3-7/8" Std Bore, 1550cc

Genuine Harley-Davidson

Flat-Top Cast Pistons, 3-7/8" Std Bore, 1550cc

22851-99A
Iron Pass £229.10£269.53View
Screamin' Eagle Milwaukee-Eight 117 Stage IV Kit

Genuine Harley-Davidson

Screamin' Eagle Milwaukee-Eight 117 Stage IV Kit

92500073
Iron Pass £2589.05£3045.94View
Stage II Bolt-On Performance Upgrade Kit

Genuine Harley-Davidson

Stage II Bolt-On Performance Upgrade Kit

92500058A
Iron Pass £447.71£526.72View
Screamin' Eagle Stage 2 Bolt-On Power Kit

Genuine Harley-Davidson

Screamin' Eagle Stage 2 Bolt-On Power Kit

92500074A
Iron Pass £474.05£557.71View
Screamin' Eagle 114CI Stage IV Upgrade Kit

Genuine Harley-Davidson

Screamin' Eagle 114CI Stage IV Upgrade Kit

92500062
Iron Pass £2589.05£3045.94View
Screamin' Eagle Stage 2 Bolt-On Power Kit

Genuine Harley-Davidson

Screamin' Eagle Stage 2 Bolt-On Power Kit

92500047A
Iron Pass £447.71£526.72View
Screamin' Eagle 4-3/8 Inch Stroker Flywheel Assembly

Genuine Harley-Davidson

Screamin' Eagle 4-3/8 Inch Stroker Flywheel Assembly

23727-07A
Iron Pass £1210.83£1424.50View
High-Compression Piston Kit, 4.060", Standard Bore

Genuine Harley-Davidson

High-Compression Piston Kit, 4.060", Standard Bore

22574-10
Iron Pass £370.46£435.83View
Screamin' Eagle 128CI Stage IV Performance Kit

Genuine Harley-Davidson

Screamin' Eagle 128CI Stage IV Performance Kit

92500094
Iron Pass £3212.39£3779.28View

Aftermarket alternatives

Aftermarket big bore kits that fit the SOFTAIL STANDARD. Genuine Harley-Davidson is listed above, not here.

S&S 131CI & 136CI BIG BORE STROKER CYLINDERS FOR MILWAUKEE EIGHT

S&S Cycle

S&S 131CI & 136CI BIG BORE STROKER CYLINDERS FOR MILWAUKEE EIGHT

In stock
Iron Pass £1321.99£1555.28View
S&S 131CI & 136CI BIG BORE STROKER CYLINDERS FOR MILWAUKEE EIGHT

S&S Cycle

S&S 131CI & 136CI BIG BORE STROKER CYLINDERS FOR MILWAUKEE EIGHT

In stock
Iron Pass £1321.99£1555.28View
S&S 4.32" BIG BORE KITS FOR MILWAUKEE EIGHT

S&S Cycle

S&S 4.32" BIG BORE KITS FOR MILWAUKEE EIGHT

In stock
Iron Pass £1321.99£1555.28View
S&S 4.32" BIG BORE KITS FOR MILWAUKEE EIGHT

S&S Cycle

S&S 4.32" BIG BORE KITS FOR MILWAUKEE EIGHT

In stock
Iron Pass £1286.62£1513.67View
S&S BIG BORE GASKETS FOR MILWAUKEE EIGHT

S&S Cycle

S&S BIG BORE GASKETS FOR MILWAUKEE EIGHT

In stock
Iron Pass £136.66£160.78View
S&S 131CI & 136CI BIG BORE STROKER CYLINDERS FOR MILWAUKEE EIGHT

S&S Cycle

S&S 131CI & 136CI BIG BORE STROKER CYLINDERS FOR MILWAUKEE EIGHT

In stock
Iron Pass £1254.45£1475.82View
S&S 131CI & 136CI BIG BORE STROKER CYLINDERS FOR MILWAUKEE EIGHT

S&S Cycle

S&S 131CI & 136CI BIG BORE STROKER CYLINDERS FOR MILWAUKEE EIGHT

In stock
Iron Pass £1321.99£1555.28View
JAMES 3 5/8" BIG BORE HEAD GASKETS FOR 1966-1984 SHOVELHEAD

James Gaskets

JAMES 3 5/8" BIG BORE HEAD GASKETS FOR 1966-1984 SHOVELHEAD

In stock
Iron Pass £33.46£39.36View
3 5/8" BIG BORE CYLINDERS AND PISTONS FOR EVOLUTION BIG TWIN

V-Twin

3 5/8" BIG BORE CYLINDERS AND PISTONS FOR EVOLUTION BIG TWIN

In stock
Iron Pass £376.13£442.50View
3 5/8" BIG BORE CYLINDERS AND PISTONS FOR EVOLUTION BIG TWIN

V-Twin

3 5/8" BIG BORE CYLINDERS AND PISTONS FOR EVOLUTION BIG TWIN

In stock
Iron Pass £283.68£333.74View
HIGH COMPRESSION 132CI & 136CI BIG BORE KITS

S&S Cycle

HIGH COMPRESSION 132CI & 136CI BIG BORE KITS

In stock
Iron Pass £1360.41£1600.48View
S&S 4.32" BIG BORE KITS FOR MILWAUKEE EIGHT

S&S Cycle

S&S 4.32" BIG BORE KITS FOR MILWAUKEE EIGHT

In stock
Iron Pass £1321.99£1555.28View