why some bikes have smaller cc but top speed is higher?

[nudgedoink]

i'm just wondering out of curiosity why some bikes have higher cc and yet lower top speed than their lower cc counterparts? even if its carb vs fuel injection, does it really make such a difference? sometimes a bike greater than the other by 75cc or so can lose out on top speed. also, like a sportsbike with 400cc for example is faster than a road bike with the same cc. why is this so?

 

haha just a curious noob

[overcrash]

i'm just wondering out of curiosity why some bikes have higher cc and yet lower top speed than their lower cc counterparts? even if its carb vs fuel injection, does it really make such a difference? sometimes a bike greater than the other by 75cc or so can lose out on top speed. also, like a sportsbike with 400cc for example is faster than a road bike with the same cc. why is this so?

 

haha just a curious noob

 

wah this is a difficult question.

 

you can compare alot alot of differences, almost nv ending

 

2 strokes vs 4 strokes

jetted carbs , dyno-ran comps

sprockets ratio

engine design ? (single piston vs in line 4 vs v-twin vs triumph's triple vs boxer)

hp to weight ratio

rider's confidence level

 

blah blah blah, its almost nv ending

[Shiloh]

horsepower.

compression rate.

torque.

bore.

rider?

[spaiduhz]

WAHAHAH! I love this question!

 

Many factors in play here.

 

Power to weight ratio. Heavier bikes need more power just to move it. Weight of the rider also plays a part, of course.

 

bore of the bike also plays another part. Short stroke, longstroke, how many RPMs the engine is capable of running on. Short stroke bikes can run at higher RPMs without damaging its conn rod and pistons and wotsits. long stroke bikes cant go all that high up on the RPMs, but it usually leads to a higher displacement.

 

Engine configuration plays another part. whether its a boxer engine, v engine or inline engine. certain bikes use engine configurations for a set requirement. V engines are responsive, and work well for twisties. inline engines are stable, and usually allows for a higher top end speed. goodness knows about boxers.

 

aerodynamics plays another part. not only it allows you to go faster without shaking, but it also allows for the bike being more efficient.

 

you dont have to look far. take a look at the harley davidson big bore cruisers.

 

Harley Davidson Road King. 165KPH top speed.

big and freaking heavy. 335KG.

1500cc V-Twin engine. Long stroke, probably, judging from its thundering sound.

not the most aerodynamic vehicle.

 

Suzuki GSX1300R Hayabusa.

much lighter, at 217kg.

1300cc inline-four engine. short stroke.

aerodynamic.

 

there are other factors, but thats on the tip of my hands.

[eedwinn]

horsepower.

compression rate.

torque.

bore.

rider?

 

Speaking of horsepower, does high CC = high horsepower?

 

If so, why are there still two categories when they're referring to the same thing?

[ben1112]

CC = displacement. HP = horsepower. Lower CC engine can make more HP den a bigger CC engine, if it's in a higher state of tune. So it's not directly proportionate. So not point refering them to only one term.

[steel_headz]

Smaller cc bikes can go fast but not stable like bigger cc...

[xiaobanz]

Weight is also impt... Like haya why izzit so heavy cos they need weight to keep their bikes down at higher speeds..

 

Some bigger cc bikes which is mentioned before has higher cc. But mostly they don't have top speed but have incredible torque which will let you fly off the bike if you aren't careful.

 

my personal preference, "top speed"

[nudgedoink]

thanks to all for the informative answers! at least i kinda got a rough idea now haha.

[endlessloop]

Hi nudgedoink,

 

Very good and interesting question!

 

In my opinion, a short answer to the question is, it all comes down to the purpose of the bike. And take into account of optimisation and trade-off. So for some bikes, it is more important to have high top speed at the expense of something else. For some other bikes, high top speed is not as useful to it's targeted audience and top speed can be traded off to gain something more useful like comfort, fuel economy and engine longetivity, costs.

 

For simplicity, instead of comparing two bikes with different engine displacement (cc), let's compare two different bike types with the same cc and they can still have different top speed. Real life examples of such cases are Yamaha R1 and Fz1 (uses the same R1 1,000cc engine block), and Honda CBR1000RR (sportbike) and CB1000R (naked street bike).

[nacl]

ignoring factors such as engine efficiency, transmission losses n rolling resistance...

 

u need only 2 numbers to calculate the top speed of any vehicle (nevermind carb or efi, engine size... these don't matter at all).

 

horsepower n air drag (frontal area multiplied by drag coefficient).

 

a search on the net will get u many many technical sites on such a topic.

 

u can ignore vehicle weight (or power to weight ratio). it only affects ur rate of acceleration n rolling resistance. but when it comes to top speed, aerodynamics is everything.

 

compare : hayabusa n zx12 (the two speed kings b4 the current hayabusa n zx14). haya has less hp, but higher top speed. answer : better aerodynamics. see : http://www.sportrider.com/tech/146_0106_aero/index.html

 

as a very rough guide, a typical bike needs half the horsepower to match the top speed of a typical car as a bike generates roughly half the air drag of a car.

 

another interest thing to take note, for a vehicle to double its top speed, it would need 8 (eight) times the horsepower to do it.

[nudgedoink]

great information people. really learnt alot from u guys. think i've got my answer, or answers!!! lol!

[SV650]

Gear ratio.

[eement]

alot of factor result it

 

gear ratio,weight,compression ratio,

[hitman]

hi all, i've got a qtn. am i right to say tat higher hp = higher top speed. higher torque = faster pick-up.?

[DeusExMachina]

hi all, i've got a qtn. am i right to say tat higher hp = higher top speed. higher torque = faster pick-up.?

 

 

Gear ratio determines top speed and accel.

 

Torque/power characteristics of an engine will let the manufacturer determine the gear ratios. If you gear a 150cc 2 stroker the same way you would a 1300cc four stroke, the 150cc bike won't even be able to accel decently.

 

Of course some bikes have electronically limited top speeds. But that's another matter altogether.