O.S. Speed R21 Euro II engine

O.S. Speed have introduced their updated R21 Euro 1/8th onroad engine with the release of the Euro II. Based on their successful Euro motor released three years ago, the engine sports a host of updates starting with the new crankshaft. To obtain more power the balance of the crankshaft was updated and now sports 3 tungsten counter weights, giving an improvement in the mid range. Another effect of this change is the return to idle has been improved. The liner now has an additional cooling hole on the exhaust side and the crankcase has been updated to cater for this. The last change is only cosmetic as the cooling head now has some updated laser graphics. Available as stand alone engine or as a combo with the TR01 exhaust and MR02 manifold for long straights in Europe.

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