use 1 shim, use the pullstart until your engine is broken in, or you will ruin your bearing, and your start shaft....$40 to replace them..., dont put anything on the gears in the roto-start...dont use diff oil on anything but inside your diffs...WD-40 makes plastic shine..dont use it for anything else, get Mobile synthetic grease for your pinion gears..its a red paste comes in a tub..$9 lasts the rest of your life. maintain your car and your bearings, or things start to fail...i'm tryin here bud