Hello all, I recently acquired an 81 CB650 and planned on changing the oil and filter right away. I however also went to turn the oil filter bolt and found it to be already rounded and stripped. I went on eBay, purchased a new one and when it arrived went to work. It however was rough and probably the mostly finicky bolt I have ever removed. The one bit of advice I do have with this bolt is this, PATIENCE. A word I'm not particularly fond of at times especially when things aren't going my way. Anyhow, I learned that after feeling completely defeated after trying nearly every (arguably good) suggestion on this post, I finally came to grips with the fact that I'm going to have to slowly work this bad boy off. At first I lathered the bolt with penetrating oil and let it sit for hours, then tried vise grips, then a plumbers wrench, then I gently hammered on a smaller socket and tried to remove it that way, but ultimately I used a combination of Sharpinski's and Gaither's advice to get this bolt out. After heating the bolt with a torch and tapping at it with a screwdriver unsuccessfully I finally wised up and decided to see what kind of tools my next door neighbor (who happens to have five bikes) had. He had both chisels and an air wrench. I then took Sharpinski's advice and made a notch in the bolt flange with a chisel. I then was able to tap the screwdriver into the bolt at a counter clockwise motion to loosen things up. This took several minutes before any change. I then had my neighbor concurrently loosen the bolt with vise grips while I tapped at it. This FINALLY broke the seal between the bolt and filter cover. That tapping motion (like an air wrench) along with loosening the nut is what actually worked. I guess had this not worked I probably would have considered welding a larger nut over the stripped bolt to see if that worked, but fortunately it didn't have to come to that. Thank you all for the input and help and I hope to see you guys around during my next motorcycle maintenance adventure.