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Top speed of a bike, among other factors, primarily depends upon its:
1. Weight
2. Peak Power
3. Coefficient of Drag
4. Rider Weight
5. Transmission Losses. (Since peak power in the spec. sheet is measured at crank, not at the wheel)

Classic 500 is capable of almost 135-140kmph on speedo which is only slightly less than what a P220 usually manages. Even though the C5 makes more peak power than the P220, the difference here is due to the aforementioned 5 factors.

Anyways, this is what I feel. I will leave it to the more knowledgeable members to explain the difference better.

RE bikes have almost fully metal parts. Whereas P220 has a lot of plastic.
Torque means good pickup. It has nothing to do with top speed. With proper sprocketing even a Splendor will do 120kmph. Like anant bro said, transmission losses also account. P220 has lighter aluminium parts in various areas. Power to weight ratio also plays an important role. And yes personally I feel bullets are less efficient machines on the paper(Pls correct me if I'm wrong). But built rigid. They were made for war purposes back then. No offence meant.

I know that bro, RE has almost everything in heavy metal part, where in pulsar engg. have worked well to make it light wait.....Speed is not my point, but my main query is how come a 500cc engine's efficiency is almost similar to a 220cc engine (even lesser if we go to accurate specification), It is just because of its wait only, As i know wait of any machine can decrease or increase the performance of the vehicle not the outcome of the engine (Correct me if i am wrong)...

Just a query
which part is made of aluminium in 220??!

These engines have different dimension.

The 500 has 84mm bore and 90 mm stroke
The 220 has 67mm bore and 62.4 mm stroke

Visualise the dimension as a four sided polygon on a 2d surface, i.e a square or in this case a rectangle, (with bore as horizontal and stroke as vertical lines) the 500 has a vertically tall rectangle , this architecture of the combustion chamber is called as a oversquare everywhere and long stroke in American :P

The 220 on the other hand forms a horizontal rectangle, this is undersquare or short stroke in American, if you stretch the top then it would become square, and if you stretch it more it will become over square.

The dimension or the architecture of the combustion chamber defines the characteristic of the engine, or in vice versa the reguired characteristic of the engine being developed will define the dimensions of the combustion chamber, in design speak.

Oversquare engines have pistons that need to travel a longer distance than Undersquare (the internals are heavier because of this (thicker c/s because of additional length and to distribute the stresses), which in turn means more internal momentum), this is one of the factor why longstrokes dont rev much.

the benefit from the over-square design is (will need clarification from someone more learnt here, i am just a mere student) that the longer duration of the stroke, gives the ports more time to fill/empty the cylinder, this simply means better volumetric efficiency for the cylinder. This equals decent amount of torque and combined with the longer duration strokes, smoother torque delivery at the flywheel. Also CR can be kept low to promote lesser stress on the internals, (you cant 'safely' increase the cr with-out better/exotic materials and manufacturing technology in your hands. safely being with out reducing the life drastically)

^these engines cannot be be over reved with any benefits. The valvetrain, port and head geometry, intake and exhaust manifold length, size ,etc are all designed to help improve the low end torque characteristic of the oversquare cylinder. over reving the engine will just cause wear and tear without any 'decent torque' output. decent torque in my definition is anything not less than peak torque the higher you go in the rev range.

These engines coupled with the tall ratio drives are meant just for cruising. period.

The Pulsar engines are a bit undersquare, cbr250 and the ninja 250 are a better example of undersquare engines. Undersquares are basically our screamers. The short stroke length (which in turn means lighter internals) is a primary reason that these engines can scream upto 12k and even 18k in the older cbr250rr i4s.

But these engines dont have a good low end volumetric efficiency, but it gets better the faster it revs (valvetrain permitting), the higher the bore/stroke ratio the lesser torque it produces in low end and higher it scales to the higher end of the rev range. These engines typically have peaky torque outputs compared to the flat or plateau torque curve you can expect from the longstrokes.

These engines paired with fairly close ratio drives can accelerate faster cause the gearboxes allows them much greater access to the torque. These engines are designed for getting the maximum acceleration possible from it. Period, (the pulsar engine is a bit squarish in this aspect because it also has to serve the purpose of a daily commuter, but the kawa 250s and honda 250s fits the bill more than perfectly)

So lets go back to the 220 beating your 500 scenario.

If the 220s is accelerating past you, it will be hard for you to catch up.

But if the 500 was already on a charge and the 220 is trying to catch up, it would be stressfull on the little 220cc

PS:220 owner here

edit:

PPS:@harishkumarko loled at the "With proper sprocketing even a Splendor will do 120kph". even if the sprockets are replaced with taller ones, the engine should be able to generate enough torque to overcome the wind resistance, chances are it wont xD.. and yes sir, your "torque means pickup, it has nothing to do with top speed" is also quite misleading.

and itsmevini123 FYI U.C.E Enfields have aluminium alloy blocks, where is the "heavy metal" here? Strip both bikes bare naked and they will weight almost the same, (enfield will be slightly heavier due to stronger engine cradle, downtube and the likes)

power to weight ratio is just a figure used by marketing people as a trump card, real performance figures are the torque output, torque in each gear output. torque to weight is also a pointless figure.

Very well explained Saerius!

With an experienced & spirited rider on the 500, it can easily give the 220 on a hard time

Thanks a lot dude . That was quite enlightening post

Thanks Saerius!!

Nicely explained, I am not very good technically as you, but it is quit understandable after some couple of read...

Wheels? Engine??

Sry abt my misleading conception. Point noted. And isn't Pulsar 220 oversquare engine(Bore x Stroke : 67 mm x 62.4 mm). And abt splendor I meant that speeds can be achieved of course with modifications(Increasing the power)

This is not an accurate statement. Even in a well executed 0-60 kmph competition, P220 zooms ahead of C500, so where's the pickup we were talking about?
Actually, low end torque leads to good acceleration at particular points only, like the initial launch. But near the redline, the Classic starts losing.

---
In short and rather philosophical way, I can say that,

The 500cc's are going towards pulling heavy loads, which means good power/ torque at all rpm's,

The 220cc's are going towards giving power/ torque, which is focused at higher rpm's only, (which results in both acceleration and top speed)

Have a 5th gear roll-on competition of C500 with P220, with 1 pillion and 50 kgs luggage each, from 30-70 kmph, and I bet Classic will win, because its made to lug loads around.

Take the example of a train's Diesel engine: Such a large engine and it can touch ONLY 140 or so kmph? Why so? Because, the larger engine size goes mainly in pulling loads, i.e. torque.

Engine can be tuned both ways:

Low end torque, mileage <------- Engine -------> Power (Acceleration and Top Speed)

actually they are diesel electrics, and dc electric motors generate tons of torque, and more linearly than any IC engine can produce.

Like i said in my previous post , visualise brother. Bore is fixed, it cannot change unless machining is done, (so for all practical purposes its solid), whats left is the stroke, which is derived from the displacement of the piston in the cylinder.

Wowwwww.... Awesomely explained bro....



and I thought it's power which defines how much load can be pulled...

Ohhh gawdd.. You confused me again. Need to visit the thread about power and torque right now...

itsmevini123..

Your logic is right, RE 500 has a bigger engine compared to the p220, so it should obviously be a more potent engine. And its very much true, but their potency are on different segments.

1) You go for a long ride, say 700kms. the p220 will get tired but the RE 500 wouldnt.

2) You go for a drag, the P220 scores but the RE 500 wouldnt.

3) Both engines are cruising at 100kmph, the p220 engine would be more stressed but the RE 500 wouldnt be, as much.
This would go by the logic said by you.

But in practical there are a lot more aspects that in real contribute to the performance of the engine.

You compare the ninja 650 and the re 500, the former by the above logic should be more potent than the re 500.

The factor that decide the character of a bike are,

1) the purpose > commuter ? sports ? cruiser.
2) Engineering (which is based on the purpose and would differ for each engine/brand, even if the purpose is same)

I

commuter - serves you the purpose of transportation
sports - faster acceleration and good topend.
cruiser - effortless to maintain speeds over a good distance.

>if you use a commuter for sports - engine will be burnt. Low in cc, so are equipment levels, engineered for purpose.

>if you use a sports as a commuter - an issue, over heating, engine not designed for lower gear-lower rpm runs.

>if you use a sports as a cruiser, long distance higher rpm - your bore wouldnt last as it would last in a cruiser, will overheat long before a cruiser would, and would more maintenance* (vibration level might increase, frequent oil change) and so would your back and butt.

>if you would use a cruiser as a commuter - would drink more oil, city driving wouldnt be zippy, less mileage.

>if you would use a cruiser as a sports - it simply woudnt move with your beat, would stress to accelerate more, top end would be good.

>if you would use a cruiser as a cruiser - no issues, effortless t cruise at any speed, wouldnt show any extra vibration (vibration comes stock, has its own graph, if not well maintained)

(Cruiser being discussed RE)


II

Engineering side

Cruiser is directly proportional to torque.

Torque is ability to deliver power at a specific rpm.
Helps in pickup, and maintaining power at a specific rpm.

RE 500 having 27.2 @ 5250rpm
&
P220 having 20.8 @8500 rpm

re is having more power but wouldnt accelerate as Pulsar does.
Because it depends upon the way the power is distributed.

The CDI or ECU,
camshaft,
crankshaft,
oversquare or undersquare bore,
Head design
transmission (gearbox),
clutch, etc..

Decides how much power and torque is required and how it is delivered.

A slim man eats 3 full meal of rice faster than a fat man, in d end who stands up and walk casually ? is directly proportional to p220 accelerating fast and re500 maintaining 130kmph.

Power affects it, but the power figure doesn't determine that directly.
For example, a bike with 128 bhp @ 14,000 rpm may or may not have enough torque at 2000 rpm. Getting my point?

You can pull loads with P220 too, but not comfortably. You'll have to rev it high, say around 4000-5000 rpm.