1963 Ducati 160 Monza Junior
The 160 Monza Jr. was based on Ducati's first 125 street bike. Many were sold in the states in basically two different forms: the round and square style. The round style is the more preferred of the two.
The engines differ from the larger OHC engines. The head bolt pattern is smaller, the cams are shorter, the valve stem size is thinner, the cases are different, the crank is different, the valve and cam covers are different. The engine sump have no cooling fins and there is an internal crank breather that blows crank pressure through a hole right next to the countershaft sprocket; therefor the absence of the usual hose coming off the top rear of the crank case.
Ignition is supplied by magneto but the lighting coil goes to a diode where AC is turned to DC which powers a battery thus providing consistent lighting and horn power.
These are delightful little bikes and are good platforms for making a custom if you want to get away from the "square look".
The model came with 16 inch wheels but 17 or 18 inch wheels can be added. The front end is lacking but the later road forks can be adapted with the use of a spacer in the steering neck.
These bikes sound great with a megaphone.
Here is what my friend Ruud did with his square style '66 Monza Junior to make it look more Retro.
He spent much money to match earlier 175/200 tank, seat, fenders, tool boxes, head lamp, larger front brake, 17'' alloy rims and 31.5 front end from the 250 Diana model to the stock 160 Monza Junior frame.
The engine is mostly stock but has a ported head with custom made "gear gazer" and standard exhaust system.
I built the engine, Ruud did the rest.
This is the nicest looking Monza Junior I have ever had part of creating.