2020 Motorcycle Previews BMW R 18 Big Boxer Motor First Look Inside (8 Fast Facts...

BMW R 18 Big Boxer Motor First Look Inside (8 Fast Facts + Photos)

BMW continues to dole out info on the new R 18 boxer bits at a time. This closer look at the motor is fascinating. Although it may look like a vintage powerplant, inside it’s pure 21st-century technology. Here’s what you need to know about the motor, which BMW calls the Big Boxer.

  1. The R 18 displaces 1802cc, and focuses on low-rpm power production. To get to 1802cc, the R 18 motor has a 107mm bore and 100mm stroke, so it is a bit oversquare. Peak horsepower is modest—just 91 horsepower is produced at 4750 rpm. However, the torque numbers are serious. From 2000 to 4000 rpm, it puts out at least 110 ft/lbs of torque. Torque production peaks at over 116 ft/lbs at 3000 rpm. Redline is 5750 rpm, and the R 18 idles at just 950 rpm.

  1. Those are four-valve heads with dual ignition. Screws and locknuts adjust the steel valves. Intake valves are 41.2mm set at 21 degrees, and the exhaust valves 35mm at 24 degrees. Fork rocker arms are employed. 48mm throttle bodies feed them. 
  1. The Big Boxer has two camshafts with pushrods. The cams are situated above, and to the left and right of, the crankshaft. They are chain driven.
  1. To smooth things out, and prevent the high-displacement engine from shaking itself into oblivion, the Big Boxer has an additional main bearing for the forged-steel crankshaft.

  1. Air and oil cool the R 18 powerplant. Those fins on the cylinder are not just for show. Also, it gets a wet sump design, along with a two-stage oil pump.
  1. Including the transmission and intake system, the R 18 tips the scales at 244 pounds. 
  1. The constant-mesh six-speed transmission has a single-disc, assist-and-slip dry clutch. A reverse gear is optional, and driven by an electric motor.

  1. No surprise, power is transmitted to the rear wheel via a shaft. It’s a universal-shaft drive, matched to a universal joint—both are nickel-plated and open, which BMW used in boxers up to 1955. The rear axle drive gets a bevel and ring gear.

BMW R 18 Big Boxer Specs

Type: Horizontally opposed twin

Displacement: 1802cc

Bore x stroke: 107 x 100mm

Maximum power: 91 horsepower @ 4750 rpm

Maximum torque: 116 ft/lbs @ 3000 rpm

Compression ratio: 9.6:1

Valvetrain: Dual cams w/ pushrod-actuated valves; 4 vpc

Fuel: Premium unleaded

Fueling: 48mm throttle bodies

Emissions: Closed-loop three-way catalytic converter; Euro 5 compliant

BMW R 18 Big Boxer Photo Gallery

Don Williams
Don Williamshttp://www.ultimatemotorcycling.com
With 45 years of riding experience, Don Williams is a fan of all kinds of motorcycles. He enjoys sport bikes, cruisers, dirt bikes, touring bikes, adventure bikes, dual sport bikes, and rideable customs. Ask Don what his favorite bike is and he will tell you, "Whatever bike I'm on."

24 of the Best Retro Motorcycles For Under $10k (2020 Models)

Although going retro can be expensive when buying a new motorcycle, there are plenty of excellent wallet- and credit-friendly choices in the visually appealing...

Harley-Davidson Screamin’ Eagle 131 Crate Engine Unveiled for Tourers

Harley-Davidson has unveiled its newest Screamin' Eagle crate engine - one that makes the popular 120R crate motor seem small in size. Meet the Screamin'...

Triumph Partners With Bajaj Auto: New Models Coming

Britain’s Triumph Motorcycles and India’s Bajaj Auto Limited will be working together to produce Triumph motorcycles in the 200cc to 750cc range. The two...

2019 Yamaha Niken GT Two-Up Test: Passenger-Friendly Motorcycle

We’ve reviewed the quirky-looking 2019 Yamaha Niken GT a couple of times, and comprehensively covered the technical side of the three-wheel motorcycle. Based on...

2020 Triumph Thruxton RS Test: Retro-Modern Motorcycle

The city of Albufeira is a sight for travel-weary eyes. Located in the Algarve region of Portugal on the Mediterranean coast, I dare say...

2020 MotoGP Schedule: 20-Round FINAL Calendar (Dates, Circuits, Tests)

Dorna has finalized the 2020 MotoGP schedule, which features some significant changes over the 2019 calendar. The 2020 MotoGP calendar grows one round to 20...