I Will Understand More When I Read The Thread, But I Suspect The Shims Go At The BaSe Of The Drum Valves, Where They Rest In The Cylinder, And Move Them Down To Open Up The Center Valve More?
they go between the base gasket, and the alum piece's to raise it all up
i did the same on my ´97 250 motor a few years ago, as i saw the hanging valves. at least at the dyno +1,5 hp more = 47,5 hp on the rear wheel
for the older kx500 motors 86-88 were only the small holes in the base gasket. why they took bigger holes in base gasket of the newer kx- modells, i will not understand.