Full transcript of “Why Aren't There Diesel Motorcycles?!”. Click a timestamp to open the video at that moment. Need another video? Use the YouTube transcript generator.
0:00 Greetings viewers. Picture this. You want to buy a motorcycle and have the funds. Your city has showrooms from all manufacturers. Let's move past sanctions and grievances. You've chosen the type of two- wheeled vehicle. It seems like a perfect combination, right? However, I know a type of motorcycle that none of the dealers will sell you, and it's a motorcycle with a diesel engine. [Music] Yes, this plot has a very loud title that doesn't quite match the action. The history of motorcycle manufacturing knows the effects of creating small-cale production of motorcycles running on diesel. But this technology has never
0:46 been as mass- prodduced as motorcycles with gasoline engines and in the context of modernity with electric motors. So why aren't diesel motorcycles doing so well? We'll figure it all out now. You're on the Crossmoto channel. Enjoy your viewing. The diesel engine named after the German engineer Rudolph Diesel is a type of internal combustion piston engine where the ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression. This is the fundamental difference of such an engine from gasoline engines which use a spark plug to ignite the fuel air mixture. Why
1:32 did such an engine appear at all? It all comes down to economy and efficiency. Early internal combustion engines were inefficient. The fuel market also differed from today. Scientists and engineers were thinking about creating a more efficient device. As far back as the distant 1824, Nicola Leonard Sadi Cararnnau formulated the idea of a thermodynamic cycle which subsequently became the carnau cycle asserting that in the most economical heat engine heating the working body to the combustion temperature of the fuel requires a change in volume that is rapid compression. Later Rudolph diesel found these ideas appealing. The first prototype of such an engine was designed by diesel in the early summer of 1893 in Auxburg. This was preceded by a long
2:17 theoretical and practical activity as well as a struggle with the onslaught of critics and the search for sponsors. No, things didn't go smoothly right away. Several more years passed before a practically applicable model called a diesel engine was ready. It was a success and by the year of 1898, Rudolph was already a millionaire from the sale of licenses for the production of his engine design. Since then, this engine has gained widespread use thanks to a number of advantages. It has a higher efficiency compared to gasoline engines. Diesel is economical. It has excellent torque characteristics at low speeds and so on. Diesel is found in ships, heat engines, tractors, buses, trucks, tanks, light vehicles, and
3:02 more. It is very rare in piston aviation and motorcycle construction. And let's touch on the latter. The situation with motorcycles is quite interesting. The history of their production knows a certain number of two- wheeled vehicles that ran on diesel. There are quite a few homemade models created by garage craftsmen. Whether in the postsviet space in Europe or across the ocean, all these are unique creations. Only about 10 manufacturers have managed to produce something resembling a small series. Off the top of my head, I can recall the American Army's Haze Diversified Technologies M130, the Dutch Tundra Track 800 CDI, the German Neander with its unique balanced two-cylinder engine, and the Indian Royal Enfield Towers. None of the major motorcycle
3:49 brands, whether it's Honda, Yamaha, Harley-Davidson, or BMW, have ever even considered creating a diesel bike. And yet, even the renowned brands that dared to try and build and launch a series of two- wheeled vehicles running on diesel couldn't capture even a fraction of the market and ceased production. It might seem like some kind of conspiracy. Some people having heard from my previous content that the track of 800 CD AI consumed only half a gallon of fuel per 62 miles and the Bakarda era around two whole 3/10 quite seriously write comments that the secret world government is pushing similar projects. It is beneficial for them that you buy gasoline at a high price and in large quantities and burn it.
4:37 [Music] It is definitely beneficial for them. But now you will understand that diesel on a motorcycle is such a steelborn topic and there was even no need to put sticks in the wheels. Let's recall the principle of diesel operation. Unlike a gasoline engine where a mixture of gasoline and air enters the cylinder in the intake phase, only air enters the diesel and the fuel will be injected into the compressed and accordingly hot air and from this temperature the fuel will ignite. To ensure the air has the right temperature, it must be compressed to a specific pressure. Internal combustion engines have such a characteristic as the degree of compression. It describes the ratio of the cylinder volume at the moment when the piston is at the bottom dead center
5:23 to the remaining combustion chamber volume when the piston is at the top dead center. The limit of the compression ratio for gasoline motorcycle engines is 14:1. In the case of diesel, its compression ratio starts at 14:1 and ends at 26:1. Keep in mind that this is a volume ratio, meaning the piston stroke in diesel engines is comparatively larger than in gasoline engines. A long stroke engine creates a large torque at low speeds. It is more fuel efficient, does not like high speeds, and overall diesels are durable and simple. All of these can be considered advantages. What motorcyclist or just an ordinary person wouldn't want to have an economical, torquy, and reliable engine in their motorcycle frame? And here
6:10 comes a series of unpleasant moments that did not allow the diesel engine to conquer its place in the motorcycle world. Any engine and its individual elements must have a margin of durability and manufacturers always seek a compromise so that the durability is sufficient for working modes and not to burden the cast iron block with a ton of weight. Since more pressure is created in the cylinders of a diesel engine, its durability must be higher. Consequently, a diesel will be heavier than an equivalent gasoline engine. And if an extra 20 to 40 kg of weight doesn't matter on the same light vehicle, it's quite critical on a motorcycle. The power unit occupies a significant percentage of the motorcycle weight. And on most motorcycles, there is a struggle for every kilogram except for cruisers
6:55 and touring bikes. And that's not all. Extra kilog are like extra centm of dimensions. Plus, a long stroke engine has longer cylinders and a larger crankshaft radius. So, a diesel is both heavier and larger. And a motorcycle is not just about lightness, but also about compactness. Secondly, due to the fact that ignition occurs from the contact of fuel with hot air, this makes combustion in the combustion chamber less controllable and more prolonged. After all, hot fuel droplets burn on the surface. The ignition of the fuel air mixture in a gasoline engine occurs many times faster since there was time, a whole compression stroke, so that everything was evenly mixed, distributed, and finally ignited. In a gasoline engine, ignition occurs from a spark plug and spreads with a combustion
7:42 front. In a diesel, the temperature of the compressed air in the combustion chamber is uneven, and ignition occurs at several of the hottest points. The symphony of vibrations in a diesel engine is what gives it its characteristic sound and also causes the engine to vibrate. By the way, to mitigate some of these chaotic vibrations, the crankshaft is made heavier, and that's another plus in weight. Some people might enjoy the vibrations on a motorcycle, but try riding a few hundred km on such a vibrator. You won't like it, and in the long run, it can lead to health problems like issues with your joints. Thirdly, to get a compact but powerful power unit, they make it rotary on a motorcycle. But high-speed rotary
8:28 is not about diesel. The only exception is the unique Niander motorcycle engine, which definitely spins up to 7,000 revolutions per minute because it's short stroke. So why not rev up the diesel to high speeds? The crankshaft engine surpassing its max calculated revolutions per minute disintegrates. That's why during the rotation of the crankshaft, the piston and the connecting rod perform a reciprocating motion. In a four-stroke engine, the piston slows down and speeds up and changes the direction of movement twice for one rotation of the crankshaft. High revving engines are short stroke with small connecting rods and pistons. In contrast, diesel engines have a long stroke and large connecting rods and pistons. Spin them at a good frequency and they will set up stalenrad. The small revolutions of a
9:14 diesel engine are determined by its geometry and the unique characteristics of fuel combustion which are effectively illustrated through thermodynamic cycle graphs. There is a diesel cycle. However, all modern engines on diesel fuel work according to the trinkler cycle. Simply put, a diesel engine needs a certain minimum time for effective fuel combustion. Specifically for those injected droplets of diesel fuel, which must have a time to ignite and burn completely. Flooring the accelerator decreases efficiency at high revs, increasing fuel consumption and ejecting unburnt fuel into the exhaust pipe. From relatively modern solutions for diesel, which directly improve its performance, this is common rail, which appeared in the '90s, but was conceived by theorists back in the
10:00 1930s. If you really want to delve into the theory of the diesel engine and the graphs of thermodynamic cycles in detail, then I recommend you a video from the Sue82 channel. Alexander, the channel's author, covered both dry theory and visual examples in his video. I left a link to his plot in the description. Someone might find it interesting. How are things with ecology these days? The last decade has seen a trend towards reducing emissions from internal combustion engines. And in order for the same diesel engine to meet Euro5 standards, it is necessary to install a mass of additional equipment on it. This can be done on a car, but on a motorcycle, it leads to an undesirable increase in mass. For example, the most massive diesel motorcycle, the Royal
10:47 Enfield Taurus, owes its successful appearance to a favorable set of circumstances. In essence, the Indians took the factory gasoline Royal Enfield bullet as a basis. They replaced the engine, keeping the original gearbox. It was produced in the 80s and '90s. It was pointless to economize. Diesel was cheaper than gasoline, and the Taurus engine could burn any wheel that was refueled in the countryside. Moreover, it consumed illegally little fuel, only about 10 L per 100 km, and was extremely simple and reliable. The motorcycle had drawbacks, weighing 10 kg more than the base gasoline model. Its power was only 6 1/2 horsepower against 22, and it could only go a maximum of 60 km/h, which it still
11:33 needed to accelerate to. Since it was a purely working horse, they generally turned a blind eye to its very modest dynamics. As they say, the main thing is that it's not on foot. In fact, Tara stopped production in 2000 specifically due to tightening environmental standards in India. And here we come to the most important reason why they don't make diesel motorcycles. The prior issues increased weight in large dimensions and reduced maneuverability are tolerable. And certainly there would be a certain number of people who would be thrilled to own a diesel cruiser or a touring bike or just a motorcycle for the countryside like Royal Enfield. But what is the main reason motorcyclists love motorcycles? Correct for the power,
12:20 acceleration, dynamics, and that driving sensation that a two- wheeled machine gives. And alas, a diesel cannot provide these sensations. Its peak power, like its specific power, is lower in weight than that of a gasoline engine. The same diesel Taurus is about three times slower than the gasoline bullet with the same engine displacement. You might say, "But there is turbo. We will boost the diesel and reduce the lag. And how many turbo motorcycles do you know? Turbo is a complication and burden in motorcycle construction, which is why it's not used on production bikes today. In fact, diesel doesn't outperform a gasoline engine. Yes, it's more economical, but any modern production motorcycle of similar power will be economical enough. Why did the same Dutch people burn out,
13:07 for example, with the 800 CDI? Creating a motorcycle, let alone a diesel one, from sketching on a piece of paper to a pre-production model is a complex and costly affair. Launching a series of equipment also costs a lot. You need to set up a conveyor, optimize technical processes, establish logistic chains, and advertise the product. Any completely new motorcycle on the market either costs more at first, or the company sells it at a price competitive with others. Take a bite in the hope of getting a quantity in the future. And if it becomes popular with the public, then they start to mass-produce it. Its cost decreases. In 1998, the Track 800 CD cost 17,500, while the BMW F800 G S cost
13:54 around 10,000 in the same year. At the same time, how much of a diesel tug fan do you have to be to pay 75,000 more for a motorcycle that is twice as slow and less dynamic? Why did the HDT30,000 turn out to be quite mass there? They simply didn't spare military money. And when state purchases ended, production went to zero. Yes, big corporations like Honda would have been forced to design a diesel motorcycle. They would have found a way to cover the costs, but why? Africans are selling pretty well, too. Big corporations have been pouring money into electric vehicle development for the last 15 years, which is why there are no diesel motorcycles. Who are they being produced for? For the tiny fraction of motorcycle enthusiasts willing to ride a heavy, poorly handling
14:41 bike that gets poor mileage and sounds like a tractor exhaust, it won't appeal to anyone. A modern motorcycle is largely a toy that's supposed to increase the rider's production of endorphins and adrenaline. In the 2020s, motorcycles are rarely used to transport wood from forests or potatoes from fields, although there are still plenty of such people, and they would probably appreciate a diesel motorcycle. Not for speed and drive, but purely for practical needs. Friends, my story is now ending. I hope I managed to explain in clear language why you will never buy a new diesel motorcycle. If you like the plot, don't hesitate to like, comment, and share it with your friends. This was the Crossmoto channel.
15:27 Until next time.
