How Much Do You Know About Motorcycle Engines?

Steven Symes

Image: Shutterstock

About This Quiz

Still get chills from the signature rumble of a Harley-Davidson? Ever been drawn into a debate over the new generation of scramblers? Whether you're a regular at Sturgis or just wondering if a Ducati might improve your commute, how much do you actually know about the "motor" part of a motorcycle?  

Without a doubt, motorcycle enthusiasts are a breed unto themselves. Some ride for the freedom they feel when they hit the road, some ride to fulfill their need for speed, and some find the sight of the road below especially exhilarating. For others, riding comes to mean an entire way of life. 

Maybe you only ride on the rare weekend, or some of your buddies act like they know more about your bike than you. But by now you've likely picked up plenty of knowledge about what actually goes vroom and why. (If you haven't, now's probably a good time to take notes for when you get stranded on the side of the road someday.) Assuming you know a thing or two about engines and you're a true motorcycle fan, you're probably qualified to take this test. We've compiled a list of 35 motorcycle engine basics for your quizzing pleasure.

Now let's see where your knowledge ranks in the pack.

How many cylinders does a V-twin engine have?

For a long time, the V-twin was the standard in the automotive industry. While some brands like Harley-Davidson used a 45-degree angle in the configuration, others chose different angles in pursuit of smoother operation.

What do you call the part that looks kind of like a can, and moves up and down in the cylinders?

As the fuel and air mixture combusts in the cylinder, it places pressure on the piston, forcing it downward. That motion is transferred to the crankshaft, so the motorcycle can move forward.

Which part inside the cylinders ignites the air and fuel mix?

The spark plugs screw into motorcycle engines, with the electrode end entering the cylinder. As the spark plug receives electrical pulses, it sparks at the tip, which burns the air and fuel, creating energy.

What part controls how and when the valves move in the engine's cylinder head?

As the camshaft spins inside the cylinder head, the lobes on it push the intake and exhaust valves to open them, and then release them so the valves close. Some people will install a performance camshaft, which has more aggressive lobes that open the valves wider or for longer, changing how the engine runs.

What are the three classic categorizations of motorcycle engines?

Of course, there are a lot of engines and types of motorcycles these days, but many people still use these three methods of classification to compare different options. That's why you'll hear someone refer to a 500 cc engine or a four-banger.

For a motorcycle engine to run, it needs what three things?

Without any of these three elements, your motorcycle engine won't run. If you have little of one, it might not run, or it could run rough and struggle. You need to constantly address any issues that could affect this balance.

What's a "single"?

As the most simple engine setup out there, singles are still a thing today, because they're easy to fix and maintain. That makes sense, since a lot of dirt bikes, adventure bikes and other rides use them, meaning the owners can take care of issues when they're far away from help.

Single-cylinder engines produce a lot of what?

Because of their design, especially one big cylinder, singles generate a ton of vibration. A large flywheel and balancers can help calm things down some. With so much low-end torque, these are perfectly suited for trail runs and racing on short tracks.

Where in the RPM range do inline-4 engines really shine?

The way most inline-4 engines are tuned gives them excellent power at high RPMs. That means you really need to rev the engine to take full advantage, but these engines deliver gobs of power for their displacement.

What's the first step to starting your motorcycle engine?

It might seem like a given, but you need to turn the ignition key to the "On" or "Run" position before you try to start a motorcycle. You wouldn't believe how many people have absentmindedly forgotten this one detail, and struggled for some time to figure out what was wrong.

How does a V-4 engine contribute to greater comfort for you as a rider?

A V-4 engine is definitely considered a luxury, partly because they make the bike a little narrower, so you don't have to spread out your legs as much. This type of engine is also more complex and therefore more expensive to make than quite a few others, which adds to their luxurious nature.

Name the part that bridges the piston and the crankshaft.

At either end of the connecting rod is an opening, allowing it to attach to the crankshaft and piston securely. This part needs to be incredibly tough; it's constantly put under extreme force by the combustion process.

How many cylinders are in a triple motorcycle engine?

Many people consider triples to be the ultimate in motorcycle engines. They offer the kind of horsepower you get with an inline-4, but are narrower. In addition, you benefit from the amazing kind of torque found in twin engines, making for a well-balanced offering.

If the oil runs dry in your motorcycle engine, what could happen?

Just like in any other engine, running the oil too low in your motorcycle can cause parts to rub against each other, generating incredible levels of friction. Eventually, those parts will fuse and not move anymore, which is when the engine seizes and is done for.

What can a clogged air filter do to your engine?

The air filter is an essential component since without it, your motorcycle engine could suck in all kinds of debris like dust, which would cause serious problems. On some motorcycles, you need to replace the filter regularly, while others you can clean and put back on. If you drive where's the air is particularly dusty, you'll need to clean or replace the filter more often.

Boxer engines are unique because the cylinders are in what position?

This truly unique design gives motorcycles with a boxer engine a distinct advantage, because the center of gravity sits lower to the ground. In addition, boxer twins have a linear power band and delivery power smoothly, plus they produce lots of torque, making them the perfect setup for a shaft-drive motorcycle.

If you pull your spark plugs and they have dark wet stuff on them, what is that likely to be?

All kinds of problems can cause what they call 'oil fouling' of your spark plugs. Among the possibilities is that you overfilled the engine with oil, or that the valve seals are failing and allowing oil into the combustion chamber. You need to replace the spark plugs and fix the underlying problem, whichever one it is.

What kind of engine does a Honda CBR600RR have?

Known for its prowess both on and off the track, the Honda CBR600RR is on the wishlist of many riders. It uses a 599 cc liquid-cooled inline-4 to complement the tight handling and excellent brakes, making this bike perfect for carving up a canyon road.

What's the area where the engine oil pools or collects?

When you pour oil into your motorcycle engine, much of it ends up in the sump at the bottom. Of course, by nature, the oil does collect on the different parts in the engine, but the pump recirculates the oil from the sump, so the cylinder head and other areas don't dry up.

The legendary Suzuki Hayabusa sportbike has a DOHC 4-cylinder engine that boasts how much displacement?

While not the largest it could be, the Hayabusa's engine is plenty potent to get this motorcycle moving in a hurry. It boasts electronic fuel injection, liquid cooling and two ram-air intakes for a setup that has become the topic of many, many discussions.

Which gear do you want your bike in when you push-start the engine?

You need to push the bike so it's moving at least 5 mph before trying to start it. If it's in first gear, the sudden power from the engine could cause the bike to jerk forward, potentially throwing you off, so it's best to use second gear for the job.

What's the danger of running a bike with electronic fuel injection completely out of gas?

If you do happen to run your bike dry, shut it off using the kill switch immediately, otherwise, the fuel pump could continue to run. The gas acts as a lubricant in the pump, so without any in there as the pump tries to run, you could do some serious damage. One time might not hurt too much, but don't make it a habit to run out of gas.

How much horsepower does the Ducati Scrambler Sixty2 produce?

Like a true scrambler, this bike is lightweight and pretty simple, and has a smaller engine. The 399 cc L-Twin not only doesn't kick out a ton of power, it's air-cooled, which helps keep the weight down. Still, it's pretty sporty, but can be handled by a new rider.

What is the big drawback of a parallel twin engine?

Quite a few cruisers, standards, and even some sports bikes have used a parallel twin engine. It has fallen out of favor with quite a few people, partly because the design is known for producing more vibrations than V-twin engines of similar size and performance capabilities.

What part of a V-twin engine is most prone to overheating?

Because most V-twins are air cooled, the rear cylinder doesn't cool off as much as the front one, thanks to aerodynamics. Still, for many, that iconic V-twin sound more than makes up for this weakness, which is why this engine has been highly popular in all kinds of cruisers, Ducatis, and more.

What kind of revolutionary engine did Honda design for the NR, which never really went anywhere?

Expensive and daring, this engine powered the Honda NR, and was studied as a highly advanced design. Not only did it have four oval-shaped cylinders, but also two connecting rods and 8 valves per cylinder.

What is "detonation" in a motorcycle engine?

You might have heard of detonation, which is an event that can seriously damage your motorcycle's engine. The fuel ignites early, pushing down on the piston as it's being forced up by the crankshaft. The connecting rod, piston, valves, and other components can be ruined by detonation, which is caused by a number of potential factors.

Liquid cooling can make a motorcycle engine what?

While some people absolutely don't like liquid cooling for motorcycles, it has some undeniable benefits. That being said, it adds weight to a bike, and sometimes finding a coolant leak can be vexing.

Which of the following is a potential cause of low engine compression?

Without proper compression, the air and fuel mixture won't combust properly, and your motorcycle will run rough, or maybe not at all. If it's not worn piston rings, the root of the problem can also be the head gasket, crank seal or scored pistons.

What kind of cooling does BMW use for the K 1600 B engine?

This powerful cruiser has a big, inline 6-cylinder engine and 24 valves, which produces 160 horsepower and 129 lb ft of torque, so you can really get moving when you need to. To keep all that running smoothly, a liquid cooling system is part of the setup.

A clicking noise in your motorcycle's engine could be a sign of all but which of the following?

While most people automatically assume the worst when they hear a ticking sound coming from an engine, the truth is a whole range of issues could be the cause. Start with the simplest possibility, low oil, and rule that out before pursuing more expensive and complicated remedies.

Revving your motorcycle's engine isn't a good idea when?

Engine oil doesn't flow quite as well when you first start up the engine, so you need to take things a little gentle at first. Once the engine heats up and the oil is flowing normally, rev away.

If you suspect your motorcycle battery is dying, what's the only sure way to know?

Really, the only way to know for sure that your battery isn't holding a charge is to have it tested. You might notice the engine is struggling to crank, or that your battery looks old, which is the perfect time to swing by the shop and rule out that possibility.

If you notice the exhaust coming from your motorcycle has a strong gasoline odor, that probably means what?

In normal conditions, the mixture of fuel and air that makes it to your engine's cylinders is balanced just right, so you get plenty of power, while most, if not all of the gasoline burns up. A strong smell of gas in the exhaust means too much gasoline is making its way into the cylinders. That, or not enough air is coming into the cylinders, or the spark isn't hot enough.

Let's say you notice the exhaust from your motorcycle has turned white and smoky. What's going on with the engine?

A number of issues could cause coolant to leak into the combustion chamber. One of the most common is a blown gasket, but damage to the engine block from overheating in rare cases could also be the source. Mechanics put the piston atop and dead center in the compression stroke, then force air into the cylinder to listen for where the air escapes, indicating the leak's source.

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