large bore

[nick28_89]

hey just wondering what is the largest but reliable bore for a 300ex....thanx

[2muchquad]

go with a 76mm piston which will give you 298cc.You could go bigger but im not sure you'll be meticulous with your oil change intervals so i'll keep you in the stock reliability range area.:)

[300exguy125]

i got a 300ex and i think the four stroke tech 330 kit is reliable check it out at fourstroketech.net you will see big power gains in the power band you get better excelleration and the kit is cheap but you have to get every thing to make it reliable such as stronger valve springs and clutch springs maybe hardened rocker arms you get a free cam for the kit if you send yer old cam so check it out