how to machine cases for big bore kits

[250r grave yard]

yes im getting a puma setup some time this week and im having to get the cases machined for the puma cylinder to fit

any machine heads out there or some one who has the know how and can direct me in the right direction on boring them correctly

if some one has a 370r that has the cylinder off or pics of a bored case halfs i would apreciate it

i could port the cases but it just take to much time and not look good

[MotoX_Racer07]

I use a bridgeport mill when I do hotrods 4mm cranks. But any vertical milling machine will work. I advise you not to "port" the cases, it would ruin the cases and do more harm then good. You want a smooth cut. I use dial indicators off of my mill head to the cases untill its perfectly centered, and remember you only actually bore it half of what the stroker is, Say 4mm you only go 2mm, total area accross would total 4mm. Best bet is taking it to a local shop and have it done.

[MotoX_Racer07]

I read your post wrong sorry, you need to bore the cases for the cylinder to fit. Same ordeal nearly, just boring the cylinder area so the sleeve fits into the cases right?

[250r grave yard]

my concern is the amount of meat that will be left or any

i have a 85mm bore going in to the bottom end the amount of meat is maybe 3/16 or smaller on ether side from the stock hole

if i were to bore the whole peice i would have some big holes before the outside sealing area

this is going on a 250r bottom end

the machine heads that will do it for nothing my friends dont know how but have the machines to do so

i really would like if some had done a big bore 250r before

to say what has to be done like if i got to fill the whole with something or if i wont get near the whole when i bore it

[woodsracer144]

any shop that can bore a cyl can bore cases, you take out as much as you have to and the open ports you cut in to you can fill with weld or epoxy... what ever you want to so...