BMW 1928 R57 494 cc ohv transverse twin frame # 25723 Engine # 70343 The 1928 BMW range comprises four models: two in the 500 cc class, the R52 sv and the R57 ohv, and two models in the new 750 cc class, the R62 sv and R63 ohv. The new 494cc models are again further developed: the front brake diameter goes from 150 to 200 mm, and there’s a new 3-speed gearbox with oil lubrication instead of the earlier grease-filled boxes. The kick starter now works in line with the crankshaft, the earlier model ...