O.S. Speed B21 Ty Tessmann II off-road nitro engine

Coming from O.S. Engines is the new Speed B21 Ty Tessmann II nitro off-road engine. The square stroke power plant follows hot on the heels of the recently introduced 110% long stroke engine and it is based on the World Championship winning B2101. It features a 5.8mm venturi insert and different from the original B2101 the Ty Tessmann II has a reshaped low-profile cooling head, of Ty’s original design, with double height vertical fins. The B21 Ty Tessmann II is available separately or including the new 90mm manifold and T-2090SC exhaust.

Source: O.S. Engines [os-engines.co.jp]