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I just bought a la sleeve 310 kit 72-72 bore stroke if im calculating this right that equates to 293cc why is it being sold as a "310". Anyways I've been told the pro x barrel has to be ported to gain full potential is this true? Would the standard porting i have be equilevent to say stock porting on a factory cylinder? Branden
 

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the 310 is the last bore on the cylinder. the port you could say is equiliant to say stock but a little better from the port layout .
 

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I think that if you calculate a 74 mm bore (max for a 310), you will come out to about 309 cc.
 

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Its just like any other cylinder stock or aftermarket, the CCs are always lower than the size the engine is listed as.
A stock R cylinder is 246cc but called a 250.

Check this out, the other day had two of the small chinese 4 stroke engines, one was listed as a 110cc the other was a 125cc. One cylinder had 107cc on the side & the other one had 123cc.This is cast into the cylinder.
Pulled each engine down, both had the same size piston & both had the same stroke crank & guess what, thats not the half of it, both of those engines measured out to be 90cc.

Boy I'm telling you :blink: , if it aint somthing.
All you got to remember is, Dec 7th 1941 a day that will go down in imfome, them ol boys kick our tails back then & looks like they are still kicking.
Neil
 

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your post above Neil is why I also asked you to confirm the cc's for kiddo's motor ;)
 
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