What performance do you get from various motorcycle engine sizes

In My Humble Opinion
1

motorcycles, scooters, ATVs and dirt bikes seem to come in some pretty standard displacements. Numbers like 50cc, 80cc, 100cc, 150cc, 250cc, 450cc, 750cc come up a lot.

So what are the levels of performance you can expect from each of those engines? I was talking to my dad a while back about motorcycles and he said with a 250cc he could manage to get up to highway speeds (he weighs 250 pounds) but he had to pretty much red line it but with a 450cc he could reach highway and interstate speeds w/o feeling he was pushing the engine too hard. So I’m guessing 450cc is the minimum engine you need for a heavy adult to drive at highway or interstate speeds w/o red lining it.

What if you are looking for something that can perform on city streets (30-40mph max) and not on highways? What if you want something that will almost always be used in the city, but occassionally needs to go highway speeds of 55?

What if you live in an area with a lot of hills?

2

It’s not so much the displacement, as it is the design. IIRC the Yamaha FZ400 had a redline of 14,000 rpm and was quite fast. ISTR that the two-stroke RD400 (?) also had a high redline and was fast for its time. I believe the FZ400 is about 10 mph faster than my 600 cc Seca II. My YZF-R1 has a 1 litre engine that makes 142 hp. Two years later they got 180 hp out of the same displacement.

3

UK perspective:

50cc and 125cc are beginner “learner” bikes that can only do 30mph and about 60mph respectively.

250cc up to 400cc are lightweight bikes you have to rev hard or change gear regularly to maintain momentum but can easily do 70mph.

600cc to 750cc are considered proper bikes that can exceed legal speed limits easily.

1000cc are big sports bikes with loads of power, can be hard to manage without experience.

1200cc are big sports tourers that can do high speed mile munching with no problems.

Bigger than that and it’s probably a cruiser / Harley / Goldwing or something. Lots of cubes but more about show than go.

Obviously the style of bike matters, a 600cc sports bike will be different on the road than a 600cc trailie bit the general pattern is there.

4

As Johnny said it’s the type of engine and not so much the size makes a huge difference. A 250 Ninja will do close to 100 and runs highway speeds with ease. A 250 Nighthawk will have a real problem getting up to those same speeds. I had a 600 Shadow that would do mid 80s but that’s about it, and 600 sport bike will really get you in trouble. For real highway riding I’d personally stay away from most 250s.

5

I’m going to send this jetting over to IMHO.

twickster, MPSIMS moderator

6

As others have replied, it’s not strictly a matter of engine displacement, it’s also to do with the transmission, weight of the bike and other design elements.

That said:

You have a lot of choices for “mostly in city riding, occasional highway hit at 55 MPH”. A lot lot.

Any motorcycle or scooter will handle hills just fine. If you’re not hot on the idea of dealing with a clutch and a lot of gear shifting through city traffic and up/down hills, you could hardly go wrong with a large-wheeled 250cc scooter like the Piaggio BV250 or Kymco People 250. Both of them come with 500cc models as well if you envision taking the occasional longer highway trip. I’ve had the Piaggio BV500 and it could easily do 75 MPH.

Smaller wheeled and/or cheaper scooters are also a possibility, but speaking from personal experience, riding on highways with 10" or 12" wheels is not a lot of fun. And also from personal experience, once you allow for “occasional” highway riding, you’ll soon yearn for longer day trips that are mostly highway riding.

On the standard motorcycle side, what type of ride are you looking for? Cruiser, dual-sport, sport bike, etc.? New only, or used/out of production OK? Do you have to carry stuff a lot or just you and a backpack or bag?

7

Displacement isn’t that closely related to performance. A 500cc Japanese sportbike will outperform a 1,500 cc Harley Davison pretty handily. Some of that is engine design and performance, some of that is superior chassis and suspension design. Anyone who’s spent a lot of time around bikes, and enjoys tweaking and modifying them, will tell you that you’ll get more bang for your buck from suspension upgrades than you will from engine modifications. Yes, you need an engine with enough power to perform safely at highway speeds. But once you’ve reached that minimum, handling matters more that more power. And more displacement doesn’t necessarily give you more power anyway (Harley Davidson being the prime example of this).

If you’re looking at something for city streets, and don’t plan to use it on highways, a scooter might be your best option. That’s exactly what they’re designed for. If you will occasionally venture onto the highways, there are freeway-legal 250cc scooters, which might be up to the job. Otherwise, something like a Suzuki SV650 will provide all the performance you will ever need.

8

Indeed. Torque output scales roughly with displacement. Power is the product of torque and RPM, so if you want high power, you need both torque AND RPM.

Example:

Honda Goldwing, 1830 cc engine. Puts out 125 lb-ft of torque, but redline is somewhere around 6000 RPM, so the peak power output is only about 118 horsepower.

Yamaha YZF-R6, 600 cc engine. Puts out about 49 lb-ft of torque, but redline is an astounding 17,000+ RPM (some controversy over where that exact line is, but no matter what, it sounds like a hair dryer going by); peak power output is 127 horsepower.

So you actually get more total power out of an engine that’s 1/3 the size.

Moreover, the smaller engine means the whole bike weighs less. R6? About 400 pounds wet. Goldwing? 900 pounds. Granted, the 'Wing has hard luggage and barcalounger seats, but even if you stripped all that junk off, it’d still be twice the weight of the R6. Less weight means it’s easier to handle, and it also means it accelerates more quickly.

The SV650 is a pretty popular all-purpose bike. I know people who use them for track bikes, and others who tour cross-country on them with aftermarket luggage.

If highway travel will be rare and/or brief, a 250 can work for you. Check out the Kawasaki Ninja 250. If you plan to hit highway speeds regularly, and want to have reasonable speed flexibility - especially if you carry a passenger or any luggage - I would avoid anything less than 400 cc’s.

If you are new to riding, smaller is better. Look for a used Ninja 250 for a couple grand, and spend at least a season getting used to riding before you try anything bigger.