i know a feeler gauge is sometimes used, i was lent one this weekend in houston at the speedline race and came in handy. it is a delta tool made by delta does anyone know where to obtain it or do they make one for a mugen sedan. guys need your help.
Look into the Team Tamale tool...it doesn't measure the spring preload, but does measure the clutchbell spacing...equally as critical. Spring preload just measure down with a caliper from the end of the crank to the top of the spring retaining nut. Take multiple measurements around the surface and average it out.