KLE 500 B6 2006 Rear brake piston size
 

Hi All

Can anyone tell me the size of a KLE500 B6 2006 model rear brake piston?.
The reason i ask is i've just bought one and it's 34mm the one i took out of the bike is 30mm the shop i bought it from say there part is right and i must have a aftermarket brake on my bike (i don't think it is)

So if anyone knows the orignal size for a B6 2006 model it would be of great help.

Thanks