I hope no one else is as unlucky as I was in losing my rear master cylinder cap and diaphragm! Unfortunately GasGas / Reiju only sells the complete rear master cylinder assembly, ie no parts available seoerately. Luckily the parts from a 2016 YZ 250 fit perfect! I think there are other years & models that will fit, however I know for certain these will.
Note: Cap is an AS3 replacement for this 18 XC300.
http://www.gasgasrider.org/forum/att...1&d=1589473413
http://www.gasgasrider.org/forum/att...1&d=1589473435