O.S. Speed 21XZ-B Ty 110% ComboThis special 21XZ B edition motor was built to Ty Tessmann's custom requirements in order to help him win of the world championships. Based on B2101, the heat sink head has a refined design for improved cooling during a race on Ty's request. It also uses a newly adopted 5. 8mm reducer to improved fuel efficiency making a crusial difference over a long race. This combo set includes a matched exhaust set using a newly designed 90mm long manifold to give