Why do harley davidsons have such big engines but are so slow?

Question

really good harley are like 1350cc, whenever i see one it always looks like they struggle to go fast, it seems to me with such massive engines they would flog sports bikes with around half the cc. im no expert or anything but im curious

Answer 1

Because motorcycle riding besides being just transportation is both a sport and a lifestyle.  And each cyclist is into bikes with varying degrees of those aspects.  And the market builds the bikes that the buyers demand.

Someone who buys a dirtbike is probably only looking at sporting reasons for his purchase.  Someone paying big bucks for a Ducati is buying both performance and status.  The companies that build these bikes are endlessly chasing better performance to satisfy their customers.

The Harley survives with awful performance because it's buyers are not in it for sport at all.  They ride bikes for lifestyle/status reasons and when they chose a bike they are buying the Harley icon status as portrayed in movies and advertising.  Their Harley must look like a Harley and sound like a Harley, this cannot be sacrificed for inconsequential things like performance.  Harley makes 'style' improvements on it's new bikes to satisfy it's customers who demand that they only make one cake but must find different ways to decorate it.

A 2007 Harley 883 is the same 40hp as a 1936 900 knucklehead, they call it tradition.  Someone more sporting would see it as an antique that lacks the benefit of actually being old.  Or a status symbol for people of low status. So we are set up for endless debate between two camps with opposite values.

Answer 2

They are very low geared. They are very heavy. They don't have much going on in the engine compared to Japanese bikes, and V-Twins overall are slow compared to inline engines.

Yamaha R1 first gear does over 100mph. A sportster does like 20...that's a guess I know it's around there.

Answer 3

slow to depreciate, yes

slow on the road, well i guess that just depends on the owner

you can drive a ferarri slow if you'd like, doesn't make it a slow car

Answer 4

As was previously stated, Harley engines are designed for torque rather than power.  They have very heavy flywheel assemblies, allowing the motor to maintain speed under varying amounts of load (i.e. up or down hills) whereas a lighter made engine would have to drop down a gear to get the engine in it's power band again.  The sheer size of the engine would imply that it should be able to have more power, and with aftermarket parts, this is true, but from the factory, it is designed to "cruise" rather than "hot rod"-- put the bike in top gear and run all day long at about 75-80 mph turning only 2500-3500 rpm... and get around 45+ mpg while doing it!

Answer 5

Because the engines are still based on a 60 year old design.

It has nothing to do with the fact they are twins plenty of twins put out massive power the new Ducati 1098r is 1200cc and about 170bhp.

Answer 6

They are for looking at , not riding.

  

I don't ride on the drag strip, so I've never been able to get a race with any FLIT CHUY bike.  Not  with my Valkyrie or my old GL1100 Gold Wing, not from off the line, certainly not from a 70 mph roll-on, and not to the next town.

Answer 7

That 1340CC engine doesn't have as much Torque as my YZF1000 either...sorry to disappoint.

As far as "if you dump the clutch it would burn out then launch....well...so would a ford escort.

As far as "class" goes... Im sorry I am laughing at that but... guys with big beards, black leather jackets, black leather pants...and skull caps...well, it just doesn't sing "class" to me.

One of the BIGGEST reasons I don't own a Harley is because I don't want that HOOD BIKER reputation that comes along with it. Sorry, Im not knocking you...ride what you ride...but don't try to make it something it isn't.

Its not FAST..its not POWERFUL..and it sure the heck isn't CLASSY.

Answer 8

Kato said it all.  I have a farm tractor with 354 CI engine (5,800 cc's) that only makes 92 horsepower.  And it's extremely slow with a top speed of maybe 20 mph.  That looks pretty poor compared to the 90-120 hp bikes out there.  But hook your burley V-Max to a 5 bottom plow (which the tractor pulls with ease) and that 2 wheeled powerhouse suddenly looks as puny as a weak kneed, pencil necked mosquito trying to pull an elephant.  Or, put that V-Max engine into the tractor frame and it would have a hard time just moving the tractor, let alone moving it at 20 mph or pulling a plow.  And even at an idle that 92 hp tractor could drag a dozen screaming, howling superbikes around like a wedding car dragging tin cans behind it.

I suggest you study engine design in depth and you'll find the power characteristics of an engine depends upon how the engine is designed and what the engine is designed for, be it a locomotive engine or a model airplane engine.  

INCIDENTLY, the 1600cc Kawasaki V twin cruiser puts out LESS horsepower than does the 1340cc Harley engine!  I'm stating fact, all you have to do is read a recent past issue of Rider magazine and their dyno report.  

HMMM, a j*p engine that's LESS powerful than a Harley!!!!  Surely this is a conspiracy of some sort!!!  Maybe Rider mag was paid off to lie or someone sabatoged the dyno or printing press.....

Answer 9

HD4me, your right

You dont need power, fuel mileage, braking, or handling.

Harleys are made for show, not for go.

Answer 10

Why does HD kick every body's butt in Pro-Stock in NHRA motorcycle drag races, and they are practicly unbeatable in AMA flat track racing. I'll drag race any metric bike with my 08 FLHX , if we both pull out in 3rd gear. As long as HD is the number one seller in the USA, they must be doing something right.

Answer 11

well, they could, but harleys dont focus on power,but rather, torque, and if the rider were to open the throttle fully, from a stand-still idle, the tire would do a burn out then launch, so....

Answer 12

First of all harley engines look big because the tranny is large and adds to the size. Next, most of the j*p bikes you see zipping around are inline 4 motors with a much higher redline, in some cases up to 15000 rpm.

Answer 13

There's a reason they are called HOG.  Sounds better than pig but it is the same thing,

They are just poorly engineered.

Good Luck...

Answer 14

They look slow so that when you grow up you can get one and take your boyfriend for a ride.

Answer 15

you should look into the screaming eagle vrods

Answer 16

That is because there are 2 cylinders instead of 4. and a Harley has a big trans. But why you are patting your self's on the back for super sport bikes consider this. The NHRA just had to give a weight to the Busa's to make them competitive with the Big Twins in Pro  Stock. The busa's could not catch them and now they are crying for more breaks to catch them. In the points standing in 07 the top five were Vtwins and the bottom five were susie's

Answer 17

A semi has a bigger engine than a Corvette but it can't outrun one. Harley's are made for low end torque not speed. I really don't understand why people have such a hard time wrapping their head around this concept. Cruisers, whether it is a Harley or a V-Star, are not built for speed and performance, they are built for cruising (hence the name). It has nothing to do with the quality of the motorcycle. It does what it is intended to do, and does it quite well. Of course for young, stupid rider that knows practically nothing about bikes (like many here obviously) this is more than their tiny little brain can comprehend. Young riders tend to measure their manhood by how fast their bike is. Once you are really a man this is no longer the case.

Answer 18

Torque not RPMs

They can be made to run but not stock bikes

Answer 19

dont need speed when you got Harley-Davidson class.  not 1350cc, thats 1340cc, Son.