NEW Screamin’ Eagle 135 Stage IV – Harley’s Most Powerful Ever

The new Harley-Davdison Screamin’ Eagle 135 Stage IV street-legal crate motor. It’s big all around.

Screamin' Eagle 135ci Stage IV engine beauty shot in black finish

Harley-Davidson has just introduced it most powerful factory street legal crate engine in the company’s history. The numbers are impressive. The new Screamin’ Eagle 135 Stage IV crate engine boasts a displacement of a whopping 2212 cc – making each individual cylinder 1106 cc or 231 cc larger than the displacement of the Harley-Davidson Nightster’s entire 975 cc mill. That is big.

But what is size if it doesn’t come with matching power?

The 135 arrives with 143 ft-lbs torque and 130 rear wheel horsepower. The torque figure is reached at 3500 rpm while the motor needs to be spun up to 5500 rpm to reach those horsepower figures. But it is the more readily available torque that will come in to greater play with this engine. (Read A Brief History of Horsepower) Harley-Davidson, in a  display of modesty, states the engine will “provide instant passing power from cruising speed.” Yes, we imagine that it will.

There are a few things that may cause a few riders pause – especially when comparing the motor to Harley’s other performance offering in its premium bikes, the 117 motor. The 135 provides 28% more torque and 41% more horsepower. The other pause inducing moment might be a result of pricing for this new mill. You had to know it wouldn’t come without a big sticker. We don’t have the Canadian price but the US$ price is going to be $7,995.95, or $8000 if the nickel isn’t going to dissuade you.

But it is in almost all cases going to more more than that. You will need a 2021 or later Harley-Davidson Touring model to bolt the new engine into and you will require a few additional parts depending on which bike you own. It does not however require additional fabrication or engine mount relocation. If you have dreams of laying down two long stripes of rubber, which this engine most certainly could accomplish, unfortunately the 135 will not fit into trike models. All the numbers were achieved with Screamin’ Eagle Street Cannon mufflers and a Screamin’ Eagle air cleaner which aren’t required but recommended for peak performance.

Harley has also introduced a new wireless tuner to get the most out of the bike while remaining emissions and warranty compliant.

Harley says the development of the new mill was in part due to the results at our favourite racing series, the King of the Baggers. The  list of specialty components includes:

New 68mm throttle body and matching CNC-machined intake manifold, originally developed for Harley-Davidson Screamin’ Eagle factory racing team engines, to maximize airflow to the engine.

Screamin’ Eagle Extreme CNC-ported cylinder heads provide significantly improved efficiency of cylinder filling, leading to more explosive power and increased rear-wheel torque when compared to stock. High-performance valve springs remain stable with the high-lift cam and in high-RPM operation.

Screamin’ Eagle Pro Billet Cam Plate and Oil Pump provides higher pressure when the oil is hot to keep pressure drops to a minimum.

New 10.7:1 high-compression forged pistons.

SE8-517 high-lift camshaft, high-performance cam bearing and high-performance tappets.

Patent-protected 4.31-inch steel sleeve cylinders and new 4 5/8-inch flywheel (bore x stroke is 4.31 x 4.625).

New high-capacity 6.8 gram/second fuel injectors.

Screamin’ Eagle Ventilator Extreme Air Cleaner and Screamin’ Eagle Street Cannon mufflers (each sold separately) are not required but are highly recommended for peak performance.


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