Hello everyone. My 520 exc last summer gave such an ugly sound to it I started a motor revision. Everything wonderful also jumped clean only the noise was still there, in my opinion it was the oil pump because it had a bit of a groove, so in the block and at the pump. Since I have no money for a new block is my question I can mill it out and make a suitable sleeve? What kind of material should the sleeve be? kbar for every answer, of course, I’m also aware that it wasn’t stupid to fix it from the beginning when I saw it… you learn from flaws.