The head on one of my chain tensioners is completely snapped off. I have tried vise grips on the remaining exposed threads (bout 3/4 inch) with no luck. Have also tried to "double nut" the thing out, but there arent enough exposed threads for the second nut to get a bite.

Any ideas? I have heard that I could weld another bolt onto the old one, so I have something to grab, but I am without welder. I really am not looking forward to buying a used swingarm on ebay and replacing the entire thing, over a damn tensioner.

 

cut a slit in it with a dermal and use a screw driver to back it out