Gentlemen,
Today I had a play and took the shells out of the big end of my 2.25Hp Bradford, I found them to have plenty of metal but found they had picked up. I cleaned the damaged area and put them around the crank pin which did not have any scoring but found some play. I very carefully filed the shell flat faces until they were a snug fit around the pin, I then looked at the bottom half of the big end with its half shell in place and found that the shell was below the end cap faces so carefully filed these flush. I also opened the lubrication holes as the shells and end cap did not match and restricted the oil getting in. After cleaning all the parts and flushing out the old oil and filling with new I refitted the parts, checked for play and tightness. I then prepared the engine for running and let her run for half an hour and the big end knock has now gone and she is sweet again. I then removed the cover and checked all the bolts and any damage, the bearing was not running hot so reassembled and ran for an hour. All still ok.
Martin P -- please replace email with snipped-for-privacy@btopenworld.com.
May the force be with you, because if she isn't you're on a hiding to nothing.