5-cylinder motorcycles you may not have heard of

Motorcycle engines follow a few good layouts, and that choice has been made over a century of trial and error. Anything from one to four cylinders, and we’re used to seeing them. However, there are some layouts that didn’t make the cut, such as the V3 engine (although Honda has something to say about that now) and any longitudinal three- or four-cylinder engine. Curiously, there have also been a few six-cylinder motorcycles, although they are so rare that only two models are currently in production.

One format that has never been popular in motorcycles is the five-cylinder engine. There have been many cars that have used it, some performance icons too, but by and large turbocharging in cars has negated the need for an extra cylinder and all the complications that come with it. Forced induction in motorcycles isn’t common, however, and considering we’ve seen six cylinders here, it’s quite surprising that we haven’t seen more five-cylinder motorcycles. With a manufacturer announcing a new five-cylinder motorcycle engine on the way, we thought it would be a good idea to take a look back at all these types of motorcycles you may not have heard of.

Honda RC148

The ’60s were a crazy time for a lot of things, but nothing embodied this crazy spirit better than racing during that era. There wasn’t a big rule book like there is now; there were only suggestions about what to do. At the time, the two-stroke engine ruled the Grand Prix paddock, but Honda always had faith in the four-stroke engine. The NR750 is proof of how hard he tried to get four-strokes working in racing, long before they became the standard choice.

The RC148 was born from that same stubbornness to prove that four-strokes were the future, but having half as many power strokes per revolution was a problem for the two-stroke machines. Honda’s solution was simple – in theory – to double the revs. An additional cylinder was also added. This resulted in a five-cylinder in-line engine with a total cylinder capacity of 125 cc (that’s a neat 25 cc per cylinder) and a speed of 21,500 rpm. Oh, and you could only hit 22,000 RPM once, for the final sprint to the finish.

This engine generated 34 hp, which, if you do the calculations, turns out to be 272 hp/liter. For reference, modern MotoGP engines produce about 300 hp/liter just 60 years later. Like a two-stroke engine, you had to keep it boiling to get the performance out of it, so it had an eight-speed gearbox.

Some parts were so small that tweezers were needed to handle them! This was also a featherweight motorcycle, with a curb weight of 187 pounds. The RC148 was a success, with Luigi Taveri winning the championship by one. It was his third championship with Honda. Having proven his point, Honda moved on to other engine configurations after the 1966 season. To our knowledge, the RC148 is the only five-cylinder motorcycle built by a manufacturer with carburetion as the fuel delivery system – and that title will remain forever.

Factory Kawasaki H2 1250

If that name sounds familiar, that’s because it belongs to Allen Millyard, the same gentleman who put a Dodge Viper V10 engine into a motorcycle chassis. Oh, and unlike the Dodge Tomahawk, the Millyard Viper V10 is street legal. The Kawasaki H2 1250 was a one-off Frankenstein build from Millyard. It took the H2 Mach IV ‘Widowmaker’ as its base and added two more cylinders for a total of approximately 1,200 cc from an inline five-cylinder configuration.

The result was about 120 hp. Consider that the stock H2 Mach IV made about 74 horsepower from its 748 cc engine and could run a quarter mile in under 12 seconds, easily hoist the front wheel into first gear and continue up to 190 miles per hour. It was rumored that it could reach over 140 MPH! To put it in context, on a good day its top speed would have been enough to set and hold the production motorcycle top speed record until the 150 MPH, fully faired Honda VF1000R came along in 1984.

Honda RC211V MotoGP bike

Honda has had quite a few experiments with four-stroke racing machines. We’ve already covered the RC148 and its success, and Honda tried to repeat that with the NR500. The street version was called the NR750 or just ‘NR’, and its level of complexity is something we’ll probably never see in a street bike again. Honda then switched back to two-stroke racing motorcycles and was very successful with the NSR500. Mick Doohan was the most successful and Valentino Rossi won his last title last year.

In 2002 we saw a shift in the rules, with preference given to 990 cc four-stroke engines. The RC211V was born with a V5 engine. This engine had a lean angle of 75.5 degrees and generated its maximum torque at 15,000 rpm. The power was over 230 hp (without traction control in 2002!). The 211 won titles with Valentino Rossi and Nicky Hayden, and the V5 layout was discontinued in favor of a 90-degree V4 when the rules changed to only allow 800cc engines in 2007. Since then, all MotoGP competitors have only had four-cylinder engines.

MV Agusta Cinque Cilindri models (upcoming)

MV Agusta appears to be on its way to becoming the first motorcycle manufacturer to produce a motorcycle with a five-cylinder engine. It calls it the “Cinque Cilindri” engine, which is Italian for ‘five-cylinder’. It is known that the Italians sometimes gave creative names to their cars, such as the Maserati Quattroporte, a four-door sedan. But seriously, MV Agusta calls it the Quadrato engine platform, which is Italian for ‘square’.

There are some extremely interesting facts about this new five-cylinder MV engine. It has two banks, with three cylinders at the front and two at the rear. It will have two crankshafts in a U-configuration, but only one cylinder head. There will be no variable valve timing, as it is not necessary to meet emissions standards. There are some real advantages when it comes to size: These engines will be narrower than an inline-four, shorter than a V4, and weigh less than 132 pounds.

The MV Quadrato engines have a cylinder capacity of 850 cc to 1150 cc. At its highest, it will generate 240bhp at over 16,000rpm and nearly 100Nm of torque at 8,500rpm, indicating an astonishingly flexible engine. That means we’ll see it in everything from power cruisers (should MV make one) to supersport liter engines (which MV will certainly make).

MV Agusta has said that the engine will debut in a model that is currently no longer in the lineup. Our money is on the return of the F4 to the range with its full 240bhp output and unrivaled top speed – and of course the title of the world’s first production five-cylinder motorcycle.