I set aside the original two speed auto mix ZA50 engine and completely rebuilt its pragmatic predecessor known as the single speed E50 engine. The cylinder was upgraded using an aftermarket tccd 50cc kit with a more aggressive port map while retaining the stock displacement. The automatic clutch was braced and tuned for later engagement. The trusty 12mm Bing carburettor and intake were increased to 15mm and topped with an MLM velocity stack. Original points were turned into Christmas tree ornaments, and in their place, an auto retarding CDI was installed…we all love a nice ignition curve at 9,500 RPMs! Finally, a nice expansion chamber was added to collectively double if not triple the horsepower.