OzVMX Forum
Clubroom => Manuals & Technical Doco => Topic started by: Tim754 on April 29, 2013, 06:34:43 pm
-
Here ya go.
Bore x bore x .7854 x stroke x number of cylinders. The bore size MUST ALWAYS be first in this equation , The figure of . (that's point) .7854 is a constant in all cc calculations.
So a standard Honda CB750 K2 is 736cc being each bore 61mm and stroke 63 mm ,, therefore it is ,, 61 x61 x .7854 x 63 x 4 = 736cc Easy when ya know the maths hey!
Did you know 1 kilogram = 1 litre of pure water at sea level ;)
-
I strongly prefer to think of it as (Pi x (Radius squared)) x stroke, when discerning the swept volume of the cylinder.
[Radius being half the bore]
[Pi being the ratio of the circle circumference to its diameter, or (C/D) which is approximately 3.14159]
[(Pi x (Radius squared))] being the area of the top of a cylinder
[stroke being the length of the cylinder traversed by the piston]
then just multiply by the number of cylinders your engine has.
Your RM465 is 86mm (b) x 80mm (s)
( ( 3.141592654 * ((0.5* 86mm bore) * (0.5* 86mm bore)) ) * (80mm stroke) ) * 1 (single cylinder)
ergo = that standard bore RM465 is indeed 464.7cc
-
Take your pick kiddies which bit to end up with the same sh......... ;)
-
What makes Tim's method easy to remember is the .7854 is the four numbers in the top left hand corner of a calculator going clockwise.
-
I assume you both forgot to divide by 1000 to convert to cc ;D sorry couldn't help myself
-
Prefer the Pi method.....because the calculator has a symbol, don't need to remember any numbers ::)
-
Feel free to add your own Manuals & Technical Doco's here............
-
Did you know 1 kilogram = 1 litre of pure water at sea level ;)
And fits in a exactly in a 100mm cube
Cheers Grahame
-
Did you know 1 kilogram = 1 litre of pure water at sea level
And fits in a exactly in a 100mm cube
Which came first: the kilogram, the litre or the millimetre ;D
-
The metre came first. Then the gram which was the weight of water that fits into a 1cm cube at its most dense temperature (4 deg C). Then a thousand of these is a Litre.
Cheers, Grahame
-
.7854 is how much of a cirlce fits into a square.
-
RM 465
Pi x Radius squared x stroke
3.14 x (1/2 8.6cm bore x 1/2 8.6cm bore)x 8cm stoke
3.14 x (4.3cm x 4.3cm) x 8cm
3.14 x 18.49cm2 x 8cm = 464.46cm3= 464.46 cubic centimeters=0.46446 litre
1cm=10mm , 1000cm3= 1 litre
-
gettin too technical for me but i'll save this page to refer to. Can use it now to work out my 70x70 stretched DT1 & 80x64 shrunk RT2, or for that matter my destroked overbored TF100 bucket racer [not run for years] using a crank [one side] from an RD200--52x46.5. Forgot i changed it to a 125 cylinder in the end so 56x46.5. But 'dumb me' not thinking--when i had my husky chainsaw apart, remember looking at the crank & measuring from centre of pin to centre of crank, looking at the verniers & thinking jeez how oversquare is 'that' [then i woke up].
-
Another interesting point, re CC.
I was told by a person that should know that a Cubic Centimetre is not EXACTLY the same as a Millilitre, and that is one reason why in modern metrication Millilitre is used and not CC.
The reason they are not identical is that the old method of getting an international standard representing one CC was not as acurate as the modern methods of measurement, and that with modern measuring standards one Litre equals about 998 point something CC.
I like trivia! (sometimes)
cheers pancho.
-
Anyone for a Trivia Thread?