This is a discussion on How do I calculate CC's ? within the Yamaha YFM660R Raptor (20012005) forums, part of the Performance /Technical category; What is the formula for figuring out my displacement? My motor is bored out .020 over in case anyone already knows....


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12062001, 08:54 PM  #4 
Senior Member

Quote:
On 20011205 22:04, ultim8warrior wrote:
What is the formula for figuring out my displacement? My motor is bored out .020 over in case anyone already knows. B = BORE cm S = STROKE cm N = NUMBER OF CYLINDERS 
12072001, 01:47 AM  #5 
Senior Member

cc's stands for cubic centimeters, couldnt you just fill it with water then peasure how much water? I dont think its a great idea to fill you engine with water thoe, maby use gas.
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12072001, 02:12 AM  #6 
Senior Member

hmm, interesting formula, but its unique, thats why I use logic, and it always works, thats why I say:
 *pi(r)^2* <formula for area of a circle times stroke, will give you area of the cylinder, times number of cylinders of course. Its easy to remember, so you never have to look it up! Just remember the area of a circle and your fine! 
12072001, 05:22 PM  #7 
Senior Member

Quote:
 *pi(r)^2* <formula for area of a circle
r = 1/2 bore pi = 4 x .7854 We know the bore and stroke, so we don't need to measure the radius. Remove the logic and it's Engine cc's for Dummies. ;) 
12072001, 11:40 PM  #8 
Senior Member

I tried badercarma's suggestion and I almost got smashed by my own 4wheeler. HOLY CRAP that thing was hard to flip over to get the water out back out.
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12082001, 01:31 AM  #9 
Senior Member

They actually do that suggestion in some sancioning bodies of drag racing to confirm that you have the displacement you say you do. You dont turn the quad over of course, you just leave the plug out and crank it over... I'm not sure what they use to fill it with, though.

02112002, 05:05 PM  #11 
Member

another "less scientific way" is to take the number of lugnuts on your bike divided by the number of links on your chain. mltipy this by the length of your swingarm and then add to the combined number of inches of travel your front shocks offer. subtract this number from your date of birth and add your current age. you now have your answer. wasn't that easy??!! :)20 :)20 :)20 :)20 :)20 :)20 thanks for the info there. obviously, yours is more informative than mine.

02112002, 07:02 PM  #12 
Primo Member

pi * radius^2 * bore
All the measurements must be in CM if you want CCs a raptor is 100mm bore and 84mm stroke so change it to cm:10cm bore and 8.4 cm stroke radius = 1/2 the bore, or 5 cm 3.1415 * 5^2 * 8.4= 3.1415 * 25 * 8.4 = 659.715cc Now .020" over = 0.5080mm so the equation is: 100.508mm bore 84mm stroke convert to cm 10.0508cm bore 8.4cm stroke plug into the above formula 3.1415 * 5.0254^2 * 8.4= 3.1415 * 25.255 * 8.4 = 666.444 So on a raptor the displacement change is 666.444  659.715 = 6.729ccs larger that's just a little over 1% larger than stock.. damn.. and I just noticed you have a warrior.. not raptor 83 bore x 64.5mm stroke same numbers apply 348.97 cc stock 353.26 bored .020 over difference of 4.29ccs <font size=1>[ This Message was edited by: RaptorBrad2 on 20020211 18:05 ]</font> 
02122002, 11:40 AM  #14 
Senior Member

pi*(r*r)*stroke divide by 1000, r is the radius of your piston
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