actual displacement of 80cc kit(well almost actual)

[dazed_maunder]

i pulled my head of today on my 80cc kit and did a few measurements,somewhat rough measurements as i'm in the us right now and my micrometer is back home but there very close,close enough to count anyways what i got for the bore size was roughly 1.84 inches and for the stroke i got 1.53 inches so bore x bore x stroke x .7854=4.06 cubic inches convert that 4.06 x 16.39=66.54cc
so fore sure the 80cc's are not 80cc and please remember my measurements ar not exact just very close

 

[spad4me]

If its a kings engine they use the olde English method and use lines of barley corn, or the length of the king's thumb to measure that is why your measurement may vary from theirs.

 

[dazed_maunder]

well I used those red sticks off of bottle rockets a pair of scisors and a standard tape measure

 

[andyinchville1]

HI,

Which engine (brand / supplier) did you measure?

Andrew

 

[Maxx Ported]

I measure my engines with a bore gauge and a depth mic. Thats Why the other day, I said each engine seems different. The bores are usually 1.850, but the stroke varies from 1.6 to 1.63..
The most cc,s I have found so far is 71.18cc
I hate being told I can buy 70cc OR 80cc, for the same price.. When I can't even measure one that large.... ( have bought over 40 engines kits)
even the head bolts vary from 1.7 to 1.825 spacing and .130 to .300 diameter

even had one box MARKED 80cc but IS a 49.18cc called to asked WHY?????? OOOOOOOOOOOo so Sorry. and nothing was done

Why can't the TRUTH be TOLD

 

[BlueCollarBikes]

If its a kings engine they use the olde English method and use lines of barley corn, or the length of the king's thumb to measure that is why your measurement may vary from theirs.

HeHeHe.

Thats funny right there.

Cheers

Bob

 

[dazed_maunder]

engine brand supplier

well Andy it was the 80cc kit i got it from powerkingshop on thEBAY,brand?who knows i have no idea who makes these things they all look the same

 

[HoughMade]

What is the volume of the combustion chamber? I'm convinced that what is being advertised at times is displacement plus the combustion chamber- that is "cylinder capacity", but obviously that is not the same as "cylinder displacement"- which pretty much all engine guys go by.

 

[dazed_maunder]

volume

volume of a cylinder is height times area of the circle so area of circle roughly but closely being 2.65 and height being roughly 1.53 you get 4.05 inches its all the same convert that into centimeters and you get 66.36cc

 

[HoughMade]

I passed 6th grade math so I know how to figure volume of a cylinder- but that is not my question. Earlier, you said the stroke is 1.53 inches- that is not the height of the cylinder. That is the length of the stroke.

The combustion chamber is the area above the piston when the piston is at top dead center....there is and must always be a space there. That space, plus the engine diplacement (bore x stroke) is the actual volume of the cylinder or cylinder capacity. However, engines are usually not measured in cylinder capacity or cylinder volume. They are measured in cylinder displacement.

Unfortunately, many people use the terms "cylinder capacity", "cylinder volume" and "cylinder displacement" interchangeably- that is not correct. My theory is that the "80cc" myth is due to incorrect language more than a deliberate attempt to mislead. The displacement of the "80" is around 70ccs (or less), but the "cylinder volume" or "cylinder capacity" may very well be close enough to round to 80ccs.

Of course to call it 80ccs is still misleading because everyone assumes it is displacement, but as we have all seen, the translation between Chinese and English can easily result in mistakes.