cc calculation?

So, tell me if I am wrong, but the stroke of the crank along with the size of the piston both effect how many cc's your bike actually is right?

If so, does anyone know how to calculate it?

Also, with all the talk of using different cylinders on puchs and such, are there any effective scooter kits or any other kits that are super effective and NOT water cooled. That water cooled stuff is silly.

Re: cc calculation?

silly but effective depending on what CR you are running. i have the formula to figure out cc's somewhere. let me find it. i really think there should be a list of scooter or other kits that were not made for puchs (only saying puchs because they seem to be the most popular) but were adapted to puchs listed on the wiki. as far as super effective in a cylinder goes you'de be looking at the largest ports (or the ability to make them large) and the highest compression possible on pump gas

Re: cc calculation?

cc= (pie) piston radius in cm ^2 (stroke in cm)

Re: cc calculation?

yay geometry!

think that should work

so if my piston is 42mm = 4.2 cm

and my cc= 70

70= (3.14x4.2)^2(stroke)

70cc = 173.9 (stroke) wait! you have to take your final answer and square it to the 3rd power i think

fuck it... i dont know. sorry im a lame 11th grader

Re: cc calculation?

One time I saw Ryan Nichols do the math in his head.

Re: cc calculation?

Almost, sammy.

Given piston is 42mm, kit is 70cc:

D = 42mm

R = 2.1cm

Bore = 2.1^2*3.142592 = 13.85cm^2

70cc^3 / 13.85cm^2 = 5.05cm stroke.

Re: cc calculation?

formula= 3.14 radius^2 stroke

for a 80metra 3.14 2.35cm squared(=5.5225) 4.3cm = 74.564795

Re: cc calculation?

Aaron McTaggart /

join scroll down to the "gallery" section. click on "specials." scooter kits galore.

Re: cc calculation?

Thanks, i havent been visiting that site for years now.

On a non-sarcastic note, thanks for the math dudes.

I know there are tons o scooter kits on there, but they are all water cooled, and honestly, I see water cooled as more of a problem than a solution. I figure if ducati can make an aircooled 1000cc sport bike, air cooled is just fine for my little moped.

Re: cc calculation?

you bring up a good point about 1000cc air cooled bikes and i'm not disagreeing with you on that point, but with 1000cc bikes there are not many times when you are doing 30mph, so there is alot more airflow over the engine. also lets say your moped is doing 65, rpm's are most likely crazy high. where as if a full sized bike is doing 65 it has a 5/6 speed transmission and the rpm's are nowhere near readline. but i agree that watercooling isn't necessary

Re: cc calculation?


the problem with the air cooled scooter kits is that they are all forced-air cooled, the scooters have cooling fans. The heat transfer rate is proportional to the velocity of air moving past the cooling surface so in order to run an air cooled scooter kit on a puch engine, or similar moped engine, you would have to add a fan, modify the cooling fins (weld extra material on?!?) or run it for short periods at a time. The difference in h, the coefficient of convective heat transfer, is on the order of 10-20 times that of a non-forced-air engine for a forced-air engine.

this is why minarellis and scooters can run cast iron cylinders without overheating, and puchs an' shit cant.

Re: cc calculation?

hence the forced air cooled e50 project...


Re: cc calculation?

just to let ya know that big hole in the other side of that fan is the INTAKE.

Re: cc calculation?

yeah i know. it'd need another whole cut on the other side. it was a mock up. planning on having a custom impeller made

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