Harley-Davidson announce Screamin’ Eagle 135ci engine

Harley-Davidson have introduced the Screamin’ Eagle 135ci Stage IV performance crate engine in the US. Based on Milwaukee-Eight architecture, the new v-twin is not only the largest, but also the most powerful street-legal engine Harley-Davidson have offered to date.

Suitable for 2021 and newer models in the Touring range (Ultra Limited, Road Glide Special, Street Glide Special, Road King Special, etc), the Screamin’ Eagle 135ci Stage IV crate engine is the product of Harley-Davidson’s success in the MotoAmerica Mission King of the Baggers road racing series and trumps the Screamin’ Eagle 131ci crate engine from 2020 in terms of capacity, power and torque.

Compared to the Milwaukee-Eight 117, which at 1,923cc, is Harley’s largest factory-fitted engine, the Screamin’ Eagle 135ci Stage IV crate engine has a capacity of 2,212cc and produces significantly more power and torque. Against the Milwaukee-Eight’s 75kW and 167Nm, the Screamin’ Eagle 135 produces maximums of 97kW (130hp) at 5,500rpm and 194Nm (143lb/ft) at 3,500rpm – increases of 29 per cent and 16 per cent, respectively.

Engineered and assembled at Harley-Davidson Powertrain Operations in Wisconsin, components in this street-tuned engine include 68mm throttle bodies and a matching CNC-machined intake manifold that was originally developed for the factory bagger race team, as well as Screamin’ Eagle Extreme CNC-ported cylinder heads.

High-performance valve springs, a high-lift camshaft, hi-po cam bearing and tappets, a Pro Billet camplate and oil pump from the Screamin’ Eagle range also feature, along with high-compression (10.7:1) pistons, new steel sleeve cylinders, a new 4 5/8-inch flywheel and high-capacity injectors.

Each end of the combustion process also gets an upgrade, in the form of a Ventilator air cleaner and Street Cannon mufflers from the Screamin’ Eagle range.

Intended as a bolt-in replacement for MY21+ Touring models (excluding trikes), the Screamin’ Eagle 135ci Stage IV performance crate engine can be fitted without frame or engine mount modifications, but does require specific header pipes and other equipment, as well as recalibration of the ECU.

In the North American market, the Screamin’ Eagle 135ci Stage IV is available in black or chrome and priced at US$7,995, backed by a two-year factory warranty when dealer-installed.

Australian availability of this engine is likely but had not been confirmed at time of writing. Harley-Davidson ANZ expect to make an announcement on its local release soon.