The next time you see a on the road, whether it’s a big GS with hard cases or a naked R Nine T, pay attention to its engine. It’s going to outlive us all.

If there had to be any symbol for BMW’s two-wheelers it’s the Boxer engine, a design in which the cylinders are horizontally opposed. I can’t imagine anything better suited to shouldering the history and soul of the Motorrad division than this:

The twin-cylinder Boxer engine has long been a staple of BMW’s motorcycle lineup. It has literally been around since the beginning of the company. The Boxer engine was the beating heart of the BFW Helios and the precursor ofmodern BMW bikes. In the Helios, however, the Boxer was mounted with its cylinders positioned fore and aft. This impeded airflow to the rear cylinder, so BMW turned the engine 90 degrees; now the cylinders poked out to the left and right. This provided equal airflow cooling to both cylinders. The rest is history — and the future, too.

Watch this video for a closer look at the modern version of the motor:

I’m still just amazed that this thing can be seen powering at least half of BMW’s current production motorcycles. This engine has been through many iterations in the near-century it’s been around, and it’s a formidable mill.

In its latest redesign, the Boxer is BMW’s answer to motors, such as the Milwaukee Eight from Harley-Davidson and Thunderstroke from Indian Motorcycles.

The Boxer is probably best displayed by the R18 introduced earlier this year. It has the most recent version of the engine, which BMW calls the Big Boxer, for obvious reasons:

I was not a fan of on first blush. It’s very much BMW’s bid for buyers in the American market, those riders likely looking at Harley or Indian cruisers. It’s big and it’s heavy. It comes with mid-controls for comfort and is meant to eat up miles. I’d rather be on a sport-tourer if I were going to travel significant distances, but the R18 does show off the Boxer engine beautifully. And I like it more today, after having seen this reworking, the :

This bike is objectively a monstrosity. I didn’t even know something could induce grille fatigue in me without, one, being a car, and two, having a grill. But the Blechmann R18 manages to do it. The bike is a gaping maw in motion. Look upon it and tremble. The rear-quarter view is better, but I imagine its profile is best because the focal point would be the motor. I could almost forgive the Blechmann R18 anything for its engine.

After seeing that, the R18 looks almost subtle to me, and I can appreciate the effort BMW made to recall its 84-year old bike, the R5.

In this modern guise, the Boxer has grown both in displacement and proportion, even gaining a roundel of its own because it remains the symbol and heart of the BMW machine its cradled in.