2 stroke bore out

[x200x]

if a 250r engine is bored .060 over is that a bigger cubic centimeter size or is it just for putting in a new top end? like if its a 250 how much is it bored out to be a 300 or 330?
thanks

[x200x]

really, no one knows???

[BGP]

.060" over is only 1.5mm over standard bore. It's for rebuild purposes. (.060 will get you from 246 to 254 is cc)

Edit: A 73mm bore will give 301cc. That's more than .275" over. (7mm)

[Sick200x]

I found a displacement calculator somewhere, don't remember where???? but just rebuilt top end on my R, 1.50mm over making the bore 67.5mm, displacement turned out to be 258cc.

[shortline10]

Bore X Bore X Stroke X .7854 = cc size , you have to move the decimal point to the left one point on the bore and stroke .

[pantera1975]

I got a PSI performace flat track ported cylinder and its 50 over now and it need a bore is there cooling issues with it being bored that far?

[BGP]

I found a displacement calculator somewhere, don't remember where???? but just rebuilt top end on my R, 1.50mm over making the bore 67.5mm, displacement turned out to be 258cc.


Ugh! Quite right, I was using 67mm for some reason.