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.

Well i've been searching a lot for answers and what i came to know is, you were half right but there are some changes

Short Stroke Engine is also called Over-square engine, the stroke is shorter than bore (Bore:Stroke > 1.2)

• Apache RTR 160 (62mm x 52.9mm)

.....


......h worlds, there's the Square engine (Bore=Stroke theoretically but can have slight variations)

Most Indian bikes come under this like

• Apache RTR 180 (62.5mm x 57.8mm) (Yes the RTR180 is not oversquare)
• Pulsar 150/180/220
• Yamaha Fz/Fazer
• Hero Hunk,Karizma,CBZ
• Honda Unicorn

5.5K is the rev limiter, thought Max power will be achieved at 4.8k itself.

I am sorry if i have caused any confusion, But if you have gone through the thread then you would have seen that it has been pointed out and i have restated, (twice i think?)

Still, i am sorry that i caused you some confusion. And i am glad to see that you have brought forth additional material to add to the knowledge base.




A suggestion to future posters. Please go through the entire thread page by page before making up an opinion and typing out a reply. This is a Thread not a Bible, and each and every word is not set in stone, This is just a record of a dialogue what a couple of people had quite some time ago, and like all discussions it has its share of bloopers, some contributed by myself. Hopefully you will find my mistakes to be rectified during the course of reading.

Also like all discussions, this one has a Head and a Tail, and the Tail of this discussion hasn't twitched for quite a bit. A more constructive course of action compared to throwing stones at the tail to make it twitch would be to start a fresh thread with a relevant topic.

Cheers

Well this thread is a bit misleading at the start. If it wasn't for the Apache ad clearly saying its over-square , i would have read your first post and believed in it. So i think it's better you edit the post on first page. (or at least leave a note on first post to read the changes in the next pages)

Guys, as this thread is already became most bioinformatic for me , I would like to clear some more of my doubt about engine and their power output....

Lets take a normal 600cc engine where in Nano it generates only 35-37 BHP on the other hand in R6 or in a CBR 600rr it generate hell around of 125-130 BHP, I know one is made for torque and another is for speed, but does any one of you know how they make these changes in engines for requirements....what changes may be in bore stroke or in anything ( I don't know) they make....

Just a thought came in my mind that what would happen if we put a CBR600 engine in a nano, we will see that nano is pulling wheelies at every red light...