Who makes Williams Custom Bikes Ltd. engines?

US EPA certification records name Lifeng Group as the engine manufacturer for Williams Custom Bikes Ltd. across 2025–2026.

Will parts from another brand fit my Williams Custom Bikes Ltd.?

A shared factory and engine size makes another brand a strong candidate, but it does not prove the part numbers match. These machines are assembled from multiple component suppliers, so measure the part you have before ordering a replacement.

US importer / certificate holder

Who actually makes Williams Custom Bikes Ltd.?

Across every model year on record (2025–2026), Williams Custom Bikes Ltd. engines were built by Lifeng Group.

Model years: 2025–2026
Engine factories: 1
Engine families: 2
Models certified: 1

The factory

Lifeng Group
Also builds engines for 4 other American brands. See the full list

Model names certified under Williams Custom Bikes Ltd.

1 distinct model designations appear on this brand's certificates. Yours should be among them — importers sometimes market a machine under a different name than the one they certified.

Chopper

Related in the registry

Where is the emission sticker on my machine?
How to decode an engine family number
Same factory does not mean same part
Discontinued brands and where parts still turn up

Source. US EPA annual certification data — EPA Certified Highway Motorcycle Test Results, MY2006-present; EPA Certified Off-Road Motorcycle / ATV / UTV / Rec Vehicle, MY2006-present. Retrieved 2026-09-07. Based on 2 China-engine certificate rows filed by Williams Custom Bikes Ltd.. Full provenance and method.