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Is a bigger engine always better?

2017 Harley-Davidson Touring models get the 107 Milwaukee Eight engine Road King air-cooled

They say there is no replacement for displacement, but a recent ride on a couple of bigger Harley-Davidson models made me think otherwise.

Like most motorcycle manufacturers, Harley updates their bikes by making bigger and more powerful engines.

The latest update is the Milwaukee Eight 107-cube (1753cc) up from the 103 (1687cc) engine. I’ve ridden all the Touring models with this engine and it is smoother, more refined and more powerful.

However, I also recently rode the Fat Boy S with the Screamin’ Eagle 110-cube (1802cc) engine. It’s bigger and more powerful than the 103 in the standard Fat Boy.

It’s also clunkier and less refined with poorer slow-speed feel and fuelling than either the 103 or 107 engines.

I am probably a bit strange, but I would rather wait for the 107 to be fitted to this model than get the limited-edition S model with the bigger donk!

2016 Harley-Davidson Fat Boy S
Harley-Davidson Fat Boy S

No manufacturer ever went broke making bigger engines for its bikes. Riders just love a big engine, especially when it comes to bench racing.

And that’s why the 600cc supersport range is dying out and race classifications have to be changed.

However, my recent Harley test rides got me thinking of motorcycles where bigger engine capacity does not necessarily make a better bike.

There can be many reasons for a smaller capacity bike being better than its larger-capacity brother.

They include better fuelling, smoother power delivery, reliability, more controllable power, greater range and lighter overall weight which usually means improved handling.

Another reason is that they are cheaper. That means you can afford the top-spec model!

One great example is the new Street Triple RS which has a 765cc engine and all the electronic wizardry so that riders can able use far more of its potential than those same riders would on a 1050cc Speed Triple.

Meanwhile, they save themselves more than $500 on the most basic Speed Triple.

Triumph Street Triple RS
Triumph Street Triple RS

Not all bigger bikes are worse than the smaller models. Often the larger capacity model comes with new technology that makes it better, like the late-model BMW Boxer engines.

But here are some other examples of where the smaller model is better:

  • The new water-cooled Bonneville 900cc models are not only smoother and better fuelled than the 120cc models, but have greater range.
  • The 803cc Monster engine is so good it is now used in Ducati’s most popular model, the Scrambler.
    Ducati Scrambler configurator
    Ducati Scrambler
  • BMW R 65 was more reliable than the bigger models that followed.
  • Suzuki’s SV650 was more manoeuvrable and smoother than the SV1000.
  • Suzuki V-Strom 650 and Kawasaki Versys 650 over their 1000cc counterparts.

Can you think of any other examples where the lower capacity model was a better buy than its bigger brother or where the increased engine capacity made it a better bike? Please leave your comments below.

  1. I totally agree. I chose a Moto Guzzi Griso 850 over the 1100/1200 which tops the range. They are actually the same frame and block so there is no difference in weight but it doesnt have the side oil cooler and a few other attachments which give it a simpler cleaner look. Additionally the lesser power to weight ratio works to its advantage in the real world as it is smoother and easier to manage as it doesnt try to tear your arms out. I suspect it will have better longevity as there is less stress in the motor and frame than in the full capacity models. Maybe I am strange though. My first ever bike was a 1975 Can Am 125 which was the same as the 250 but with a smaller piston.

  2. ” BMW R 65 was more reliable than the bigger models that followed.” well this statement has opened a can of worms, apart from the dreaded clutch spring on my R80 g/s going once in just over 3000,000 km before I traded it in on a R100g/s found it a better bike than the R65 my mate had, he was always doing something to it…. of course good luck to anyone finding either of these models, ….. hmmmn wonder if I could make a new one out of BMW factory parts?
    great write up though, think that as you get older you might make smarter choices & find the bike your happy with.

    1. Good luck finding a BMW R65? Oh, wait I have a 1984 BMW R65LS in my shed along with my 2015 Indian Chieftain. Nowadays I ride the BM on monthly rides with our local Historical Motorcycle Club, I still haven’t done any work on it other than the occasional new battery. As I have had this bike from new there is no way I will ever part with it.

  3. GPz750R vs GPz900R
    RZ250 vs RZ350
    Katana 750 vs Katana 1100

    this could be a long list…

  4. IMO the sweet spot for engine capacity is 650, 750. If you go larger then you run it problems with gearing and fuelling , I.e. Top gear is too high and can’t be used until your highway speeds. Some bike seem to be able to overcome it but not all.

  5. Don’t know about the BMW r65, looked after mine, and….. mufferlers rottet out, Coils died, rocker needle bearings wore through, wobbled above 120kph in a lean, diff seal leaked, carb diaphragms got holes in them. But other than that I had it for 11 years.

  6. Why has Kawasaki Australia decided to cease importing their range of large Vulcan cruisers?

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