Forged Piston Kit — Milwaukee-Eight 107

CP-Carrillo forged piston kit for Milwaukee-Eight 107 Harley-Davidson engines — the same pistons serious engine builders spec for high-output baggers. Forged in the USA from high-strength 2618 aluminum alloy for strength under boost, nitrous and high compression.

Race / competition use: this is an engine performance component. It is not legal for use or installation on pollution-controlled vehicles operated on public highways in California, and it cannot be shipped to California.

FITMENT

• Engine: Milwaukee-Eight
• Application years (CP-Carrillo data): 2017–2022

Not sure it fits your bike? Email info@norcalbaggersupply.com — email is the fastest way to reach us — and we'll confirm before you order. You can also call 916-626-9030 (Mon–Fri, 9 AM–5 PM PT).

SPECIFICATIONS

• BHM8107-4 — Bore 3.937 in, stroke 4.375 in, 10.5:1 compression, dome 4 cc, compression height 1.143 in, wrist pin 927-2250-20CP1C, ring set CPN-3937
• BHM8107-9 — Bore 3.937 in, stroke 4.375 in, 11.0:1 compression, dome 8.7 cc, compression height 1.143 in, wrist pin 927-2500-20CP1C, ring set CPN-3937

Kit includes two pistons, ring sets, wrist pins and clips. Made in the USA by CP-Carrillo.

INSTALLATION

Professional installation by a qualified engine builder or machine shop is required. Cylinders must be bored and honed to the finished piston size, and ring end gaps, piston-to-wall clearance and deck height set to CP-Carrillo's specifications for your build. Pistons only — cylinders and gaskets are not included.

QUESTIONS RIDERS ASK

Is this a complete kit?
Yes — each set covers both cylinders: two pistons, ring sets, wrist pins and clips.

Does it fit my 2023.5+ Milwaukee-Eight?
CP-Carrillo's application data for these part numbers covers 2017–2022 Milwaukee-Eight engines. If your bike is a 2023.5 or newer Gen 2 model, email us first and we'll confirm the right part number with CP-Carrillo before you order.

Can I order a single replacement piston?
Singles exist in CP-Carrillo's line for service work. Email us the part number off your piston and we'll price a single through our dealer account.