250r cylinder

[jeffatc250r]

I have this cylinder that i purchased about 4 years ago and had it on one of my bikes untill recently, i never noticed till now but it has 2 extra ports in the top section, what are these intended for? The bike always seemed to have no low end grunt but screamed up top a lot more than my other cylinders. Theres also a picture of a stock cylinder for reference.

[200x newby]

yeah i have those to. except mine are on the bottom the guy i baught mine from said it was ported what are they for....

[3leggeddog]

somebody drilled those for extra air to travel through there.are they directionally drilled up?like towards the top of the jug?

[Jason Hall]

Yup those are extra boost port holes. They let more air & fuel travel over the piston Into the pipe to make your pipe work better than before. The pipe actually pulls air through the cylinder because of a pressure drop from the shape of the pipe.

[jeffatc250r]

Yes they are pointed up. So is this made for more top or is it supposed to be for all around performance??