Summary

• Parallel twin engines are gaining popularity on account of their simplicity, cost-effectiveness, and flexibility in varied bike frames.
• The two foremost configurations of parallel twin engines are 180° and 270°, referring to the crankshaft angle and firing order.
• A 270° parallel twin provides a extra direct throttle response, smoother vibrations, and a throatier exhaust word in comparison with a 180° parallel twin.

The days of inline-four screamers are coming to an finish, because of emission norms. Four-pot screamers produce glorious energy and a easy driving expertise however are costly to supply and never one of the best for the surroundings. On the opposite hand, V-twins are enjoyable however troublesome to bundle in a brief wheelbase chassis. And boxer twins are area of interest and thumpers — nobody likes thumpers, besides the KLR 650.

This leaves manufacturers with parallel twin engines. These engines are easier in design, cheaper to design and manufacture, and produce tractable energy that can be utilized in the true world, not solely on the monitor. Plus, these engines are compact and will be fitted in a wide range of frames with out a lot trouble. But these parallel twins are available in two in style flavors: 180° and 270°. What do these numbers imply, and why must you care about them? Here’s all the pieces it is advisable to find out about totally different parallel-twin configurations.

In order to provide the newest and correct data potential, the info used to compile this text was sourced from the producers and different authoritative sources, together with Car Throttle.

180° vs 270° Parallel Twins: Inner Workings

When it involves parallel twin engines, a number of variations exist, however immediately, the one two that the majority bikers must know are 180° and 270° parallel twins. So what do these levels point out? They consult with the crankshaft angle inside the engine; merely, it’s how the pistons hearth in comparison with each other. Let’s get into them.

180 Degree Crankshaft Explained

Just a few years in the past, the most typical sort of parallel twin engine was the one with a 180° crankshaft. Here, the crank pins are positioned on the reverse ends of one another, i.e., at 180° from one another. So, when one piston is at Top Dead Center (TDC), the opposite piston will probably be at Bottom Dead Center (BDC), and when one rises, the opposite falls.

This comes right down to the firing order of the engine. In a 180° parallel twin, the primary cylinder fires, the crankshaft rotates 180°, after which the second cylinder fires. When the primary cylinder completes the ability stroke and enters the exhaust stroke, and that’s when the second cylinder fires. Then, the primary cylinder enters the consumption and compression strokes earlier than firing once more.

Since we’re talking about four-stroke motorcycles here, there’s a huge firing hole within the engine, giving the engine an uneven firing order. The second cylinder enters the ability cylinder 180° after the primary cylinder, and the crankshaft must rotate 540° earlier than firing once more. As a consequence, the firing order of a 180° parallel-twin engine is 180°-540°-180°.

270 Degree Crankshaft Explained

On the opposite hand, you’ve gotten the burbly 270° parallel twin, which has lately turn into the most popular type of parallel twin engine on the market. This configuration can be known as a crossplane crankshaft engine; yep, the Yamaha one. Like the 180° parallel twin, the cylinders are located side-by-side, however the firing order is totally totally different.

In a 270° parallel twin engine, the primary cylinder fires, the crankshaft rotates 270°, after which the second cylinder fires. So, when the second cylinder fires, the primary cylinder has solely accomplished half of its exhaust stroke. For the following combustion inside the engine, the primary cylinder must cowl the second half of its exhaust stroke (90°), adopted by consumption and compression strokes.

As you possibly can see, when one piston drops, the second piston follows it three-quarters of a rotation behind. This provides the engine an uneven firing order of 270°-450°-270°. However, the interval at which each cylinders hearth is smoother, leading to a significantly better and extra direct throttle response. Plus, the firing order is much less uneven than a 180° parallel twin.

Popular 180° Parallel Twin Motorcycles

• Kawasaki Ninja 400 and Z 400
• Kawasaki Ninja 650 and Z 650
• Honda NX500, CBR500R, and Rebel 500
• CFMoto’s 400, 650, and 700 collection

The Difference In The Real World

If you thought the above part acquired a bit technical, you’re not alone. Mathematics isn’t our strongest go well with, both. So, let’s check out what these two configurations of parallel twin engines deliver to the desk on the highway — what these variations imply while you trip your bike.

Power Delivery

One of a very powerful facets of a motorbike is energy supply; lazy energy supply is boring and frantic is fun — assume a Honda Gold Wing vs a KTM 890 Duke! In most instances, a 180° parallel-twin provides a extra linear energy supply, and on this configuration, peak energy and torque are delivered excessive up into the rev vary. These bikes are extra high-revving however could really feel a bit uninteresting within the mid-range.

On the opposite, a 270° parallel-twin provides energy supply that’s just like a V-twin engine — each have basically the identical firing order. So, peak energy and torque are delivered within the mid to excessive vary, after which they taper off into the redline. As a consequence, these engines don’t rev as excessive however supply a extra keen and energetic energy supply, which is arguably extra enjoyable on the streets.

Throttle Response

Power supply and throttle response are carefully associated to one another, however don’t confuse the 2. The latter refers back to the method the engine reacts to your throttle enter. Here, 270° parallel twins are the higher alternative. This is as a result of this configuration basically eliminates inertial torque. What’s that, you ask?

In a 180° parallel twin engine, the crank pins are positioned on the alternative ends of one another, so the crankshaft slows down when each the cylinders hit TDC and BDC after every stroke. This phenomenon ends in the engine feeling “heavier” or providing a barely uninteresting throttle response. 180° parallel twins are also prone to rev-hang sometimes. On the opposite, 270° parallel twins remove this because the cylinders don’t attain the TDC and BDC on the identical time, leading to a extra direct throttle response.

Vibrations

Let’s get one factor straight: parallel twin engines are vibey and might by no means be as easy as an inline 4. With that out of the best way, a 180° parallel twin is often the extra vibey one of many two configurations. This sort of parallel twin produces a rocking couple, which will be eradicated with a stability shaft, however you’ll nonetheless really feel it, particularly if the engine is a pressured member of the body. There’s additionally a whole lot of nitty-gritty about major and secondary vibrations, however let’s depart that for physics lectures.

No shock right here, however 270° parallel twin wins right here. The forces from the 2 pistons cancel one another out partially, so the vibrations aren’t as unhealthy because the 180° crankshaft. The engine nonetheless vibrates, however producers use a balancer shaft to remove them. And in contrast to the 180° parallel twin, this engine doesn’t have an unbalanced rocking couple. The result’s a pleasing buzz throughout the rev vary that you’ll really feel however received’t be bothered by.

Exhaust Note

The three variations talked about above are technical, imperceptible to novice riders, and never deal breakers. However, the soundtrack is what affects people’s buying decision with regards to selecting between a 180° parallel-twin bike, just like the Kawasaki Ninja 650, or a 270° parallel-twin bike, just like the Yamaha YZF-R7.

Thanks to the uneven firing order of the 270° parallel twin, which has similarities to that of a 90° V-twin, the exhaust word is throaty and pulsing. This is why some parallel-twin engines sound like V-twins. On the opposite hand, 180° parallel-twin engines actually sound like lawnmowers or high-revving thumpers. The former is the clear winner right here, little question about it.

Popular 270° Parallel Twin Motorcycles

• Royal Enfield Interceptor 650, Continental GT 650, and Super Meteor 650
• Yamaha YZF-R7, MT-07, and Tenere 700
• Aprilia RS 660 and Tuono 660
• Honda Africa Twin
• KTM 890 Duke and 890 Adventure R
• Norton Commando 961
• Modern Triumph Bonneville Range

Don’t Forget The 360° Parallel Twin

Before 180° parallel twins have been all the trend, 360° twins ruled the automotive market across the world. In this engine, the pistons transfer up and down on the identical time with a good firing order. The first cylinder fires, the engine rotates 360°, then the second cylinder is fired; the firing interval is 360°-360°-360°. This ends in a easy engine, however the soundtrack, throttle response, and traction aren’t one of the best.

Wait, how is traction affected by the firing order? Thank you for asking. An uneven firing order provides what is called a restoration hole in traction because the energy supply is pulsing. On the opposite hand, if the firing order is even, the ability is delivered continually with none pulsing, so the wheels don’t have time to get well from any traction loss. This is why V4 engines with their uneven firing order blast out of corners significantly better than inline-fours, except for the Yamaha R1, which uses a cross-plane engine.

Popular 360° Parallel Twins

• Kawasaki W800
• Norton Commando
• Old Triumph Bonneville
• BMW F 800 GS
• BSA A65

Pick Your Flavor (We’d Pick A 270°, Though)

Let’s handle the ant within the room; if you happen to love the Kawasaki W800 or basic British twins, you in all probability don’t care a lot about throttle response, energy supply, and vibrations. In that case, a 360° crankshaft shouldn’t be a difficulty. But if you happen to like trendy bikes which are satisfying to trip and sound nice, it is advisable to take note of the kind of engine your subsequent bike has.

As it stands, motorcycles are moving into parallel twins, and selecting the mistaken one will solely make you hate these stunning engines much more. So, if you happen to favor a tractable but high-revving and sporty parallel-twin bike, choose a 180° parallel twin bike. But if you happen to favor extra mid-range grunt, higher cornering, and a burly exhaust word, don’t choose something apart from a 270° parallel twin bike.

Parallel Twin Sports Bike Performance Comparison: Kawasaki Ninja 400 vs Aprilia RS 457

(Specs sourced from Kawasaki and Aprilia)

In the top, at all times trip the bike you wish to purchase. Theory could say 100 issues, good and unhealthy, a couple of explicit engine, but when it tugs at your coronary heart, down the drain goes physics. Pick a motorbike that you just take pleasure in driving, even when it’s acquired a 360° parallel twin, a lazy boxer twin, or a thumper.