Screamin' Eagle
Performance Parts

Screamin' Eagle was born in 1983 inside Harley-Davidson's Custom Vehicle Operations division, the same engineering programme responsible for CVO flagship motorcycles. Over four decades, the brand has grown from a handful of bolt-on parts into a full factory performance catalogue — assembled at Harley-Davidson's Powertrain Operations facility in Milwaukee, Wisconsin, to the same tolerances as the original engine components that leave that plant every day. The NHRA Pro Stock Motorcycle programme and AMA Flat Track competition have both been powered by Screamin' Eagle-developed components, and the lessons learned on the strip and the dirt oval feed directly back into the road parts you can order today. Forty years of that competitive feedback loop sits behind every camshaft profile and every combustion chamber port in the SE catalogue.

You'll sometimes see the range written as Screaming Eagle — the correct name is Screamin' Eagle, the apostrophe marking a deliberate Harley-Davidson stylistic choice rather than a typo. They are the same product range. Whether you search for "Screaming Eagle air cleaner" or "Screamin' Eagle Heavy Breather", you're looking for exactly the same part.

The four-stage system is worth understanding before you spend anything. Stage I is entirely bolt-on — a high-flow air cleaner and performance exhaust slip-ons, no machining, no ECM remap required (though recommended). You'll feel 5–8 hp and noticeably stronger pull from low revs; the 9:1 Stage I compression ratio runs happily on standard pump fuel. Stage II is where the bike's character really shifts: performance cams — SE-255 or SE-203 profiles — are added on top of the Stage I work, and the rev range opens up in a way that air and exhaust alone can't deliver. Budget 10–15 hp on top of Stage I gains, and plan for an ECM remap — it's not optional at this point. Stage III goes further still: larger-bore cylinders increase cubic inches, and you're looking at 15–25 hp over stock depending on the platform — not a tune, a different engine. Stage IV is the full factory build: CNC-ported heads, 68mm throttle body, high-lift cams, displacement taken to 131 or 135 ci. On a Milwaukee-Eight, that's 121 bhp and 149 ft-lb of torque. It changes what the bike is.

At Iron Stable, we stock the full Screamin' Eagle range as an authorised UK dealer, fulfilled from Leeds Harley-Davidson — a franchise dealer with decades of hands-on Harley experience. Every part is genuine, factory-boxed, and covered by Harley-Davidson's own warranty when dealer-installed. If you're building a commuter, a strip machine, or a full-fat touring bruiser, our team can help you navigate the stage ladder and find the right combination for your specific model year and engine.

Racing Heritage

Screamin' Eagle's motorsport credentials run deep. The programme's roots in NHRA drag racing established the engineering credibility that makes the road parts so trusted; the same performance principles that push a Pro Stock Motorcycle down a quarter-mile strip in under seven seconds are refined into street-legal camshaft profiles and ported cylinder heads. AHDRA (American Harley-Davidson Racing Association) competition history stretches back to the programme's founding, and the drag strip's unforgiving feedback loop — where thousandths of a second separate winning from losing — has shaped every generation of SE development. "Designed to Race. Engineered to Win." isn't marketing copy; it's an engineering philosophy with more than forty years of competitive results behind it.

The Screamin' Eagle exhaust range spans three main families, each engineered for a different combination of performance and road compliance. The Street Cannon mufflers sit at the top — the highest-performing option in the range, built with race-grade construction and the kind of deep, authoritative sound that the performance exhaust market has spent decades trying to replicate. High Flow catalytic mufflers are the 50-state and California road-legal option: quieter than the Street Cannon, but still a measurable step up from the stock exhaust in both flow rate and power output. CVO-style catalyst mufflers are designed to match the visual language of CVO flagship models — the right choice when aesthetics and road compliance need to work together.

All road-going Screamin' Eagle exhaust systems carry ECE certification and are fully MOT-compliant. Stage IV race-spec configurations — the straight-pipe Street Cannon setups — are track and competition use only, and will fail an MOT noise test if fitted to a registered road bike. If you're building a road machine, the 49-state or California-compliant SE exhaust listings are the ones to look at; product pages will indicate certification status clearly.

The Street Cannon turns the stock V-twin note into something that demands respect — a deep, deliberate thunder that carries at low revs without becoming a droning monotone at motorway speed. It is the sound Harley-Davidson riders have chased since the 1980s: present enough to announce your arrival, composed enough to live with on a four-hour run up the A9. The difference between a stock exhaust and a Street Cannon is the difference between a working motorcycle and one that sounds like it was built for something.

Installation varies by configuration. Most slip-on mufflers are a 30–45 minute garage job — two bolts, a clamp, and a gasket — well within reach of any home mechanic with basic hand tools. Full header systems take longer and benefit from ECM recalibration once fitted; the additional flow changes the fuelling requirement enough to leave performance on the table if you don't remap.

Our team at Iron Stable can advise which exhaust configuration best suits your specific model — whether you're building a road bike, a strip machine, or something in between. Call or email before you order if you're unsure; it's a five-minute conversation that can save a return shipment.