So my yamaha warrior atv quad has a piston in it, the guy told me its bored .50 over.. what does that mean?

Does that mean its not a 350 cc anymore? what cc would it be with this bored over?So my yamaha warrior atv quad has a piston in it, the guy told me its bored .50 over.. what does that mean?
the yamaha warrior has a bore and stroke of 83mm x 64.5mm. that means the the hole where you discovered the piston is, is 83mm in diameter. the stroke, or how far the piston travels from top dead center to bottom dead center ( total distance that it moves from top to bottom before it starts to come back up again ) is 64.5mm. using a formula for calculating displacement, it figures out to be 348.98cc or 349cc. If you have it all down correctly, the staing of .5 over would be in millimeters or .020" ( 20 thousanths of an inch ) overbore. that would mean that you now have a bore of 83.5mm calculating out to be a displacement of 353.2cc or 353. If he told you it was bored 50over, he may also be talking inches. .fifty thousandths of an inch convert to 1.27mm so the bore is now 84.27mm. you now have a displacement of 359.74cc or 360cc. Most cylinders, not all, have the capability to be taken to an overbore of .080" or 2mm. Now, did the guy tell you .5mm or 50 over. Little bit of a difference there. Boring isn't to make more power, it's for getting the most use out of your cylinder. Want more power? that's a different question.So my yamaha warrior atv quad has a piston in it, the guy told me its bored .50 over.. what does that mean?
it means that the mechanic bored your cylinder 0.50 (fifty thousandths of an inch) bigger than it was.



mechanics do this to take any scorn marks that have occurred in the engine,the mechanic also does what is refered to as "cross hatching" this is done so that the new piston rings will seat (allow oil to go in the cross hatches reducing heat in the engine,and it also allows the engine to have good compression as well).



with out doing a cross hatch in the cylinder it would cause your piston rings to wear out fast,lower compression ratio,and excessive engine heat which will cause cylinder scoring.



as far as gaining any CC you wouldn't be gaining hardly anything,be that 0.50 is equal to .5 mm you would have to convert the half millimeter to cc,and being that cc is bigger than mm it would be a fraction of a cc.





CHEERS!!!!!!!So my yamaha warrior atv quad has a piston in it, the guy told me its bored .50 over.. what does that mean?
If 4 cylinder, then 350 for real, as they tend to be 348cc as standard. but called 350.



If 2 cylinder. start at 248 and get bored to 249



(that's adding 0.5 to each pston - you can't ust do one or it blows up.)
It means the stock bore is now .050 of an inch bigger in diameter.