Keith Black flat top piston set is .040 oversize with an 8.6:1 compression ratio for 1984-up Big Twin Evolution models.

VT No: 11-2221
Keith Black flat top piston set is .040 oversize with an 8.6:1 compression ratio for 1984-up Big Twin Evolution models.
The Keith Black 390 hypereutectic alloy is cast in a permanent steel mold which makes it possible to build a light weight piston that makes more power and uses less fuel and lasts longer. Pistons are .040 over sized, for a 3.498" bore and has a 8.5:1 compression ratio. The low heat transfer of the alloy keeps the skirts cool so piston expansion is minimal. The combination of a low heat transfer piston alloy and high compression ring placement increases power and economy. The high ring placement alone reduces detonation and increases the top ring temperature. **Note:Run engine at moderate speeds for at least 500 miles, avoiding excessive running in lower gears, in order to properly break-in new pistons and rings.
Fits:
FXR 1984-1994
FXD 1991-1998
FLST 1986-1998
FLT 1984-1998
FXST 1984-1998
UOM: 1 - SET
Country of Origin: Imported

Manufacturer: Keith Black
2018 Catalog pages: 183

2017 Catalog Page: 183

V-Twin Manufacturing Part Number: 11-2221
Manufacturer: Keith Black
Manufacturer Part Number: KB258 .040

Harley-Davidson & Indian OEM Cross Reference Part Numbers:            

Replacement Items:
11-1367 - 80" Shovelhead Piston Ring Set .040

Detailed Instructions: CLICK HERE!