I recently rode down to Spain on the Commander. the only problem was that the ballast resistor went. I had been told that the bike would run without one. I joined the wires and the bike ran perfectly. does anyone know if there is likely to be any longer term consequence? Also SAE 40 diesel oil is readily available in country garages, it says (in English) that it is a heavy duty detergent oil sutable for trucks etc. it is marked as API CF/CD. Any thoughts on its suitability for our rotaries.
There is plenty of information on the Rotary Owners Club website regarding oil. The silkolene classic two stroke oil seems to run cleaner and doesn't tend to stick the seals up too much. While a few members do still run on Rotella or a similar 40 weight oil, the way ahead IMHO is the silkolene product, It is available through the ROC with a good discount (provided you are a member) You should be getting around 450 miles to the litre so with an oil tank capacity of 4 litres the range is good on "internals" as they say in the helicopter world.
Let's pretend we did not meet yesterday and I will try to answer your ballast resistorquestionfor thebenefitof others.
Firstly I know nothing about the rotaries so I will have to assume the ballastresistoris there for the same reason as on the Commando MkIII.
You have a 6V coil that is in series with the ballast resistor, the whole is fed with 12V so 6V is lost as heat in theresistorand the other 6V is used by the coil. Now when you press the starter button the volts could drop considerably to the coil so the starter relay has a power feed direct to the coil without going through the ballast resistor. Thus you get a good strong spark. The good indication of the ballast resistor going open circuit is the bike will start as long as you have your finger on the starter button but dies as soon as you release. On the Commando you have the same effect if you have the kill switch on kill. I do not know about the rotary.
As regards the actual question, I would suggest it is a really bad idea to run for any length of time without the ballast resistor as the coils will get warm(er) and whatever is driving the coil will be supplying twice the current. OK maybe for a get you home fix but not for long term.