318 issues

I had a bike that would fall on its face when you throttled it. It was a plugged main jet on the carb. Idled just fine. check for accelerator pump shot off idle and try shooting some carb cleaner down all the carb holes (bleeds, etc) with the little tube provided while ideling. Id also check your advance mechanism. pop the distributor cap and suck on the vacuum line, the plate should rotate smoothly and snap back when you release pressure.