Westport Innovations' (NASDAQ:WPRT) stock has been on a tear since May 1, climbing 35% following a strong earnings report.

In the video below, Foolish contributor Jason Hall looks at what's happening with Westport, and helps investors understand what moves should be considered. Additionally, he talks about Wesport partner and competitor Cummins (NYSE:CMI), suggesting some investors should give this titan of the engine business a close look as well.