Has any of the rebuilders in here ever run into cylinders that can't be glaze busted or honed ??? We have three of them now... a 25, a 26 and a 27 they will not hone. It is almost like they are nickosil cylinders, but they take the same rings as all the others. The latest one is a 25hp CH25 spec 68606 and we ran the hone in it and it won't touch it at all. We bored one of them so we could use it. We still have 2 more here yet that I didn't want to bore. We even took one to the machine shop and asked him to try it , he put pressure on the stones and even went to his rough stones... barely left a mark in the bore. Only thought other than a crome bore is a lot of hours on it possibly overheating and causing it by heat treating the bore ??? Any thoughts or knowledge ?