Hello, is there a difference in the size of a piston for 2007 -2012 bikes and 2013 engines? Reason I ask is I have just done engine rebuild on my sons 2010 bike, kicked it over and it all went solid. Stripped it down again and it seems as though the piston is hitting the head. Timing is all fine. The part number for 2009 piston is 13101-KSE-670 but the part number on the box of the new piston is 13101-KSE-A70 which is for a 2013 onwards engine.
Thanks in advance.