be sure you get the tensioner into its little locating well when you reassemble it,,ive just taken apart a 550 motor i just bought and found this,,the engine had been disembled for inspection then put back together and not run,,just as well.
![](http://i857.photobucket.com/albums/ab139/dave500_01/miscued.jpg)
along with a 61mm bore and no rings fitted save for about an eighth of a one piece oil ring and only one clip on each wrist pin.