Motori Minarelli made headlines at EICMA in Milan last month as the Italian motorcycle company unveiled an all-new two-stroke engine that meets the Euro5 homologation.
Motori Minarelli developed an all-new 300cc two-stroke engine that meets the latest emission standard.
The engine is build based on Yamaha’s 250cc two-stroke engine.
The engine is a single-cylinder 300cc unit designed and developed in-house based on the Yamaha YZ250 enduro engine and will soon make its way to the upcoming Fantic XE300 enduro machine.
The XE300 is expected to hit the European market sometime in the summer of 2023.
However, while the XE300 is still an off-road focused motorcycle, the engine could find its way to the street bike thanks to meeting the strict Euro5 emission standard.
That begs the question, how did Minarelli achieve this?
First and foremost, the engine features electronic fuel injection, an electric start, and an exhaust valve to optimise low and mid-range performance.
The engine also features a decompression system that helps to reduce mechanical momentum at start-up, allowing the bike to restart easily after a stall.
However, the fact that Minarelli managed to acquire Euro5 homologation means that there is a complex technology underneath the engine case.
As such, the engine might pump out less than 50hp than the rest of its two-stroke buddies in the same segment, but we can expect a smoother power delivery up the rev range.
One thing for sure, this could mark the return of street-legal two-stroke motorcycle in the future.
Yamaha India has confirmed that the iconic Yamaha RX100 will make a comeback in India.
The new generation Yamaha RX100 will get a new powertrain.
The RX100 will feature the same retro design and will be the first retro bike to make a comeback in India.
During a recent interview, Yamaha India chairman, Eishin Chihana, confirmed the news.
Chinana said that the company is considering launching a new RX100 in the country, but it will no longer feature the same two-stroke motor due to the strict emission standard.
However, considering Yamaha has a host of products up for launch until 2025, the RX100 could only make an appearance in 2026.
Moreover, with Yamaha’s India bike portfolio currently ranging from 125cc to 250cc, it might take a while before the RX100 could materialise.
In addition, Yamaha is also working on a new electric scooter that is set for launch in 2025. Also, the recently launched NEO and E01 will soon find their way to India.
Nevertheless, the RX100 will be the first retro bike set to make a comeback in India. While there is no specific timeframe for the official unveiling, the confirmation by Yamaha India’s chairman is enough to get us excited.
The world of motorcycle Grand Prix in the 70s and 80s were dominated by 500cc two-stroke monsters and one of the best ones was the Suzuki RG500 piloted by the likes of Barry Sheene and more. In the last two years, Team Classic Suzuki raced their restored beauties at the Isle of Man TT Classics category by Danny Webb. (more…)
Kami telah menunjukkan bagaimana sebuah enjin empat lejang berfungsi, kini, tiba masanya pula untuk memahami bagaimana sebuah enjin dua lejang berfungsi.
Pengeluarannya telah dihentikan namun masih ada banyak lagi enjin sebegini di atas jalan raya mahu pun dalam pertandingan atau perlumbaan.
Sebuah enjin dua lejang adalah sebuah enjin yang ringkas dan oleh kerana itu ianya lebih ringan.
We’ve shown how a four-stroke engine works, now it’s the two-stroke’s turn.
Production has been phased out but there are still many on the roads and in competition.
A two-stroke is simple hence lighter in weight.
We’ve covered how a four-stroke engine works and even took a peek inside the combustion chamber of one previously (click here for the article and here for the video), so it’s only right that we show how a two-stroke works this time.
While production of new two-strokes has been fully phased out, there are still many on the road and in competition. Fans this engine format love the simplicity, light weight and most of all, the power.
A two-stroke performs all the necessary functions of intake, compression, power and exhaust in one up-stroke and one down-stroke of the piston, within one complete 360o revolution of the crankshaft (1 RPM). A four-stroke, on the other hand, completes all four tasks on each separate stroke in 720o revolution of the crankshaft (2 RPM). This means the two-stroke produces twice the power stroke of a four-stroke in every 2 RPM.
Consequently, a two-stroke is twice as powerful as a four-stroke of the same capacity. In theory, anyway.
Let’s watch the video below:
As you can see, a two-stroke engine does not utilise poppet valves like in a four-stroke. That means it doesn’t require a cam chain or belt, camshafts, buckets, shims, springs, etc. in addition to the valves. That equals simplicity and weight savings.
The type seen in the video is the simplest variety, which uses the crankcase and underside of the piston as charge pumps. As such, this arrangement is called a “crankcase-scavenged two-stroke.”
When the piston rises on compression, the bottom of the piston creates a partial vacuum in the crankcase. The piston uncovers the intake port on the cylinder wall and the combustion mixture rushes in to fill the crankcase.
As the piston nears top dead centre (TDC), the sparkplug fires and combusts the mixture. The pressure of the combustion drives the piston back down, transferring the energy to the crankshaft.
On its way back down, the piston now uncovers the exhaust port, allowing the burned gasses to exit the combustion chamber. The piston also compresses the mixture in the crankcase simultaneously.
As the piston travels further downwards it starts to uncover the transfer port. The pressure created by the piston pushes the charge (combustion mixture) into the combustion chamber via the transfer port.
The process then repeats, with the piston first closing the transfer port.
Because the charge is constantly pumped through the crankcase, this makes it impractical to lubricate the crank and piston using pumped oil circulation like a in a four-stroke. The lubrication had to be therefore premixed i.e. lubricating oil mixed with the fuel or injected into the crank bearings with a metering pump such as Yamaha’s Autolube system. Yes, this is the 2T oil you and I are familiar with.
One more thing! Keeping the throttle closed while the engine is revving high will kill it. The oil pump is actually attached to the throttle, which means no 2T gets through when its closed. That’s why the 2T is mixed directly to the fuel, but this may cause sparkplug fouling, on the other hand.
Because the oil is mixed with the fuel, very little of the oil is actually combusted. This leads to the oil being ejected into the atmosphere, hence the pollution. Additionally, some of the fresh charge (unburned fuel) gets mixed with the exhaust gases and escapes through the exhaust. This is why you’d see two strokes having a sheen of black oily goo surrounding the exhaust header and exhaust pipe’s tip.
This is why two-strokes are phased out. There have been many developments over the years to make two-strokes cleaner but they have yet to be made practical for motorcycles.
One last thing: If a two-stroke is supposed to be twice as powerful, why are the 500cc two-strokes slower than 1000cc four-stroke bikes in MotoGP?
Running the engines on a dyno to produce high power output is one thing, but it’s another in real-life applications. A four-strokes generally spread their power throughout a wider range in the powerband but a two-stroke’s powerband is usually limited to a very small range, hence called “peaky.”
For a rider, a wider powerband means he could use it to exit corners easier. This translates to better lap times and higher top speeds, since he could open the throttle earlier. Well, this is just part of the story. There are many other aspects in play, also. We’ll save that for another article, so stay tuned!
Acara Art of Speed Malaysia 2017 akan menghadiahkan satu hadiah utama yang cukup istimewa pada hari Ahad ini dalam bentuk sebuah motosikal dragster Yamaha RXZ Twinboss.
Motosikal dragster RXZ Twinboss ini dijana oleh dua enjin dua lejang yang bekerja seiring dengan gabungan kapasiti sehingga 270cc yang bersamaan dengan sebuah motosikal lumba empat lejang middleweight dari segi kapasiti.
Acara Art of Speed tahun ini akan diadakan dari 29 hingga 30 Julai 2017 di MAEPS Serdang jadi pastikan anda berada di sana sewaktu mereka
mengumumkan siapakah pengunjung yang bertuah yang boleh membawa pulang si buas ini!
This year’s Art of Speed Malaysia 2017 will be giving away a very special grand prize on Sunday in the form of a Yamaha RXZ Twinboss dragster motorcycle.
The RXZ Twinboss dragster is powered by two two-stroke engines which run in tandem in a combined capacity of 270cc which is equivalent to a middleweight four-stroke sports bike by capacity.
This year Art of Speed will be held from 29 to 30 July 2017 at MAEPS, Serdang so be sure to be there when they announce the lucky attendee to bring this baby home!
As Malaysians who are deep in the motorcycle scene or industry, there’s no denying the fact that two-stroke motorcycles play a huge role in the how the motorcycling scene has developed through the years. While other motorcycles do play their own respective roles, the two-strokes have been in the scene longer than anybody else and have created both good and bad reputations. (more…)
KTM has finally taken the covers off their latest fuel-injected two-stroke motocross bikes for 2018; the KTM 250 EXC TPI and 300 EXC TPI.
The new ‘Transfer Port Injection’ (TPI) technology has two fuel injectors that fires directly into the transfer port without the need of pre-mixing the fuels.
This new fuel-injected technology for two-stroke engines means that it can greatly improve power delivery, lower fuel consumption and requires no messing with for the air-to-fuel ratio for different riding conditions.
It’s finally here, ladies and gentlemen. KTM has finally unveiled their latest masterpiece in their two-stroke motocross line up. Unlike previous motorcycles that they have launched before, these motorcycles represent the new era of two-stroke technology where KTM has combined it with fuel injection capabilities. (more…)
Two 2018 Husqvarna two-stroke models will feature their fuel injected technology
Husqvarna TE 250i and Husqvarna TE 300i
This just in; Husqvarna is cooking up a couple of their popular two stroke engines with fuel injection technology for the year 2018. With the ongoing trend of gaining more efficiency and power, it is no surprise that the Swedish bike manufacturer is following the steps of their Austrian counterpart, KTM. (more…)
After many rumours that have been circulated for the past few months, KTM has finally announced their plan to build a fuel-injected two-stroke engine that will be put into production. This new technology by the Austrian manufacturer is called the “Transfer Port Injection”. (more…)
