My first engine from 2009 up to my last one in 2014 had that spring. I've owned, built, and worked on at least 50 motors, and never saw one without it. I don't understand how your clutch would work without it. Does your clutch plate just rattle around loose? There'd be no tension when you pull the lever on the bars, and your clutch would just engage and disengage whenever you hit a bump or turned a corner, unless I'm missing something. ..