Forged piston set. 8.5:1 CR with 112cc head. Standard replacement. Piston weight 456gr. Piston pin weight 97gr. Piston pin dia. .791" / offset. Head type: Dome with -47.6cc. Compression height 1.450". Bore 3.437". Stroke 3.969". Rod length 7.440". Cyl. length 5.330". All KB forged pistons are made from 4032 alloy; a 11% silicon alloy that is formed in a forging press. Forging aluminum gives a superior strength and structural integrity on a molecular level; after which it is fully machined. The combination of this alloy and the forging process allows the piston to flex under detonation; or pre-ignition; giving the best resistance to cracking. Although 4032 has a low expansion rate; it is higher than the cast Hypereutectic. Therefore forged KB pistons will require about .001" wider piston to wall clearance. Pistons are sold as sets; complete with wrist pin retaining rings; wrist pins and piston rings. Please note that all KB forged pistons come equipped with offset wrist pins / piston pins. There is a front and rear section on the piston and it is necessary to install it in the correct way. Please refer to the installation instructions; as provided with each piston set; prior to installation.

88" (3-3/4") to 95" (3-7/8") big bore conversion forged piston set. 9.25:1 CR with 85cc head. Piston weight 350gr. Piston pin weight 89gr. Piston pin dia. .927" / offset. Head type: Dome with -6.7cc. Compression height 1.263". Bore 3.875". Stroke 4.000". Rod length 7.667". Cyl. length 4.938". All KB forged pistons are made from 4032 alloy; a 11% silicon alloy that is formed in a forging press. Forging aluminum gives a superior strength and structural integrity on a molecular level; after which it is fully machined. The combination of this alloy and the forging process allows the piston to flex under detonation; or pre-ignition; giving the best resistance to cracking. Although 4032 has a low expansion rate; it is higher than the cast Hypereutectic. Therefore forged KB pistons will require about .001" wider piston to wall clearance. Pistons are sold as sets; complete with wrist pin retaining rings; wrist pins and piston rings. Note: All KB forged pistons come equipped with offset wrist pins / piston pins. There is a front and rear section on the piston and it is necessary to install it in the correct way. Please refer to the installation instructions; as provided with each piston set; prior to installation.

Forged piston set. For 96" (3-3/4") to 103" (3-7/8") big bore conversion. 9.5:1 CR with stock 85cc head. Piston weight 335gr. Piston pin weight 89gr. Piston pin dia. .927" / offset. Head type: Dish with +6.9cc. Compression height 1.076". Bore 3.875". Stroke 4.375" (4-3/8"). Rod length 7.667". Cyl. length 4.938". Note: All KB forged pistons come equipped with offset wrist pins / piston pins. There is a front and rear section on the piston and it is necessary to install it in the correct way. Please refer to the installation instructions; as provided with each piston set; prior to installation.

Forged big bore conversion piston set. Used for converting 96" (3-3/4" bore) and 103" (3-7/8" bore) to 110" (4" bore) big bore. With dished piston domes. Works with all stock cylinder heads; 96" and 103" with 85cc chamber and SE; MVA and CVO with 95cc chambers. 9.5:1 CR with stock 96"/103" 85cc head. Piston weight 350gr. Piston pin weight 89gr. Piston pin dia. .927" / offset. Head type: Dish with +13.3cc. Compression height 1.086". Bore 4.000". Stroke 4.375" (4-3/8"). Rod length 7.667". Cyl. length 4.938". Note: Will not work as bolt-in with OEM H-D 4" big bore conversion cylinders in OEM 96" & 103" crankcases. The cylinders will hit a small step in the crankcase. Also clearance between piston skirt and crankcase must be checked at bottom dead center. Cases with a large cast-in bump; just below the machined area for the cylinder sleeve; must be machined for adequate piston skirt to crankcase clearance. This is on both front & rear cylinder exhaust sides of the crankcase. Note: Will not fit 110" CVO models. Note: All KB forged pistons come equipped with offset wrist pins / piston pins. There is a front and rear section on the piston and it is necessary to install it in the correct way. Please refer to the installation instructions; as provided with each piston set; prior to installation.

Compatible with stock cylinders and heads; gives stock compression ratio. 8.5:1 CR. Piston weight 370gr. Piston pin weight 97gr. Head type: Dome 0.656" / Dome -57cc. Compression height 1.450". Bore 3.4375" / Stroke 3.969" (3-31/32"). Rod length 7.440" / Cyl. length 5.330". Comes with T6 heat treated 390 Hypereutectic cast pistons with 16% silicone levels which enables running a very tight clearance for longevity and hardly any piston noise. Note: Top compression ring will need additional clearance. See instructions.

8.5:1 CR. Piston weight 350gr. Piston pin weight 97gr. Head type: Flat top. Dome +1.5cc. Compression height 1.375". Bore 3.4980". Stroke 4.250" (4-1/4"). Rod length 7.440". Cyl. length 5.550". Comes with T6 heat treated 390 Hypereutectic cast pistons with 16% silicone levels which enables running a very tight clearance for longevity and hardly any piston noise. Note: Top compression ring will need additional clearance. See instructions.

8.5:1 CR. Piston weight 350gr. Piston pin weight 97gr. Head type: Flat top. Dome +1.5cc. Compression height 1.375". Bore 3.4980". Stroke 4.250" (4-1/4"). Rod length 7.440". Cyl. length 5.550". Comes with T6 heat treated 390 Hypereutectic cast pistons with 16% silicone levels which enables running a very tight clearance for longevity and hardly any piston noise. Note: Top compression ring will need additional clearance. See instructions.

Pop-up high compression. 9.5:1 CR. Piston weight 392gr. Piston pin weight 97gr. Head type: Dome. Dome -9cc. Compression height 1.375". Bore 3.4980". Stroke 4.250" (4 1/4"). Rod length 7.440". Cyl. length 5.550". Comes with T6 heat treated 390 Hypereutectic cast pistons with 16% silicone levels which enables running a very tight clearance for longevity and hardly any piston noise. Note: Top compression ring will need additional clearance. See instructions.