Hi,
Let me say that you do have a problem. Hopefully a MINOR problem, but note it could be serious. My B7100 had all of the symptoms that you describe, and mine turned out to be serious.
(1) Cooling System. I know that I sound like a broken record on this board, but if I can save an engine or two then it is worth it to me. The B7100 has a "thermo-siphon" cooling system; it has no thermostat or water pump. It is a good design, but a lot of people have problems with it because it is different from normal automotive cooling systems. The thermo-siphon system works because of the natural fluid flow that occurs as the coolant heats up. However, it is CRITICALLY important that no more that 50% antifreeze be used in the coolant (per the owner's manual instructions). Having too much antifreeze stops the natural coolant circulation and an overheated engine will result. It is also very important to keep the radiator clean.
Note: The B7100's alternator is mounted behing the fan in a way that makes it look similiar to a water pump. If you have doubts as to whether it is a water pump or alternator, note the electrical wires going to it, and also note the lack of any thermostat bypass hoses.
(3) Blowby. The smoke coming out of the valve cover breather tube is called blow-by. On my B7100 engine that had overheated, the compression rings went bad on two of the three cylinders, allowing cylinder pressure to blow by the piston and into the oil pan, and then through the oil passage ways into the valve cover and out the tube. The blow-by first manifested itself as light smoke, then heavy smoke, then oil dripping out of the tube, then oil pouring out of the tube.
(4) Whistling Overheat Warning Device: This is a simple design that takes advantage of the coolant overflow tube exhaust to activate an attached whistle to provide an audible warning of an overheat condition. I have seen some (newer?) B7100s that have the whistle installed, but most of the B7100s that I have seen do not have installed.
You need to minimize engine operation until you correct the overheat condition. Then hope damage to the engine hasn't been too great.
If I can help any further, let me know.
Kelvin