If you’ve heard of JAP, you’re probably very well-versed with vintage motorcycles. JAP stands for John Alfred Prestwich, which is the company founder’s name. JAP got its start at the beginning of the 20th century in England, making motorcycles until it decided that manufacturing engines made more business sense.
JAP was one of the biggest engine manufacturers in Europe from the 1920s to 1930s, and quite a number of motorcycles actually had JAP engines in them. JAP created larger engines, however, the bigger engines were destined for use in airplanes and not motorbikes.
For Pavel Malanik, a Czech builder with a fascination with the V8 aircraft engine, he would, unfortunately, run into a hurdle even before he started work on his project back in 2017. The JAP V8 is now an extremely rare motor with only two to three examples known to have survived the sands of time. One JAP V8 is on display in the London Science Museum, cutaway for the display. Malanik used the museum’s display to recreate the motor himself, taking pictures prior to starting his project.
Replicating an engine that’s over 100 years old is no easy task. With no template to work with, Malanik had to make the entire motor from the ground up. With help from a milling machine and a friend with a five-axis CNC machine, he was able to recreate the motor. Everything in the recreated V8 engine, apart from the roller bearings and eight spark plugs, was made from scratch. It took more than five years to draw up the plans, manufacture the parts, and put everything together.
Gallery: Pavel Malanik JAP V8 Motorcycle
The end result is a gorgeous motorcycle with an exposed valvetrain and artisanal finishing all around. The engine comes in at 4.4 liters (4,144ccs of displacement), and it makes massive horsepower, at least for an engine that was designed in the early 20th century. With its displacement, the engine cranks out a massive 50 horses at 1,300 RPM. In all seriousness, however, the horsepower figures are massive but the 184 foot-pounds of torque are big. The idle speed for this motor is pegged at about 200 rpm. There’s so much torque that Malanik had to forgo the more period-correct belt drive for a dual chain and sprocket setup.
Surrounding the engine is a home-built frame that takes inspiration from early motorcycles, with no rear suspension and just a front fork handling the damping duties. There are seats under the saddle for some added comfort, but I reckon that this bike will be very uncomfortable to ride. At 260 kilograms or 573 pounds, it’s not a light bike and to counteract the weight the tire pressures have to be inflated to a staggering 72 pounds per square inch.
The bike was well received once it was completed. Malanik entered it into a show in Prague, and it was crowned with the Best of Show award at the Bohemian Custom Motorcycles Show that happened early in March 2023.