Recenly bought a sherco 02 200 had new bearings piston basically full rebuild but it has a terrible knocking noise any ideas any 1 it sounds terrible but its not effecting the bikes performance it´s more rapid than my friends beta rev 3 2007 only other annoying thing is the clutch plates sticking when u 1st start riding it but it sharply sorts it´s self out been told this is common in shercos is this true any advice would b appreciated thanks