Well Sir,The author of this thread seems to have drawn offense at this comment. Am I correct to think that boring a chainsaw cylinder would be a rather unusual event, hence your comment?
If anyone is routinely boring chainsaw cylinders, I am not aware of it.
As much as I hate wishy-washy answers the answer is yes/no. It is possible to bore a saw cylinder but it would not be practical with the saw that was being discussed. The end cost would far exceed the value of the saw. The MS650 has a blind cylinder (non removable head) which makes it very hard to bore. If you were to bore it then you would have to have the jug re-lined as the boring would remove the lining. I used to have US Chrome re-line stock blind cylinders to original specs. As far as I know they have since quit doing so although they still will re-line "through bore" (ones with a removable head) which the MS650 does not have. If you did find someone to bore a blind cylinder, then you would have to have it re-lined, after that you would need a custom piston made and let me tell you Wiseco is not cheap.
Now are there "big bore kits" for saws......Of course so. The are not stock cylinders that are bored. They are manufactured new with the correct bore jug and the correct piston. Generally made in China.
Now will you find oversized pistons for McCulloch saws.....yes indeed. That is because they are actually for the kart engines that are a "through bore" and have a steel liner. A steel/iron bore cylinder can be bored without the need to re-line it. It is some sorts comparable to a small block Chevy.
I can go into more detail if needed