150cc upgrade no machining

[jdikov]

HI all,

This may sound dumb coming from me but I really have not been keeping up with the 150cc upgrades. So I am looking to add a big bore kit upgrade for my customers that does not need machining and was wondering if anybody could tell me what the largest size bore I can order is that does not require machining. I want something that my folks can just install and go without any extra work.

thanks for the help,

John