Dnepr - Improving the Oil System

This mod addresses the oil pressure issues in the Dnepr engine. High pressure oil fed by the oil pump through a passage in the front crankshaft bearing holder has to "jump" to a corresponding orifice in the front main bearing journal of the crankshaft. The journal rotates in an orifice in the cover and the two diameters are machined to very close tolerances between each another in order to keep too much oil from seeping through. The space is not sealed however and it grows bigger due to wear on the front main bearing, resulting in a further drop in oil pressure. The impact also damages the surface of that area of the front journal. Our solution was to machine the cover to fit two seals in it, sitting behind and after the orifice on the journal and thus preventing any oil from escaping anywhere else than through the hole in the journal. This also prevents the journal from hitting the aluminium cover as the bearing wears out. We also polished the journal to provide a smooth surface to the seals' lips. This should increase oil pressure dramatically and, as such, greatly improve lubrication of the connecting rods' lower bearings. At the very least, it should put an end to the oil pressure problems that became apparent after 30 km of riding (the oil thinned out due to heat and pressure loss became critical).