Yattaman

The story of Gan Takada and his girlfriend Ai Kaminari, two mechanics who use their quirky inventions and mecha to fight crime as the masked heroes "Yatterman". Their most regular enemy is the Doronbo Gang, consisting of Doronjo, Boyacky and Tonzura, who are trying to steal the Dokuro Stones (Skull Stones) rumoured to point the way to the largest treasure trove of gold in the world. (tvtropes.org)