Hello everyone:- I have an old Danica engine. Am told it is German manufactured. This engine is a v-twin, atmospheric intake valve type. One cylinder is missing but looks to have been about 500 CC. disp. It has to be from the early teens as it only has an exhaust valve train. The intake valve is opened by piston suction on the downward intake stroke. Any information on this speciman would be very much apreciated, thanks in advance.