Ryk, my hypothesis is based on the following; 1. fuel leaking past an injector when the engine is at rest and not influenced by cylinder/piston compression will leak past rings at some rate regardless of ring/cylinder wall condition simply because of the low viscosity of gasoline. 2. the problem is unlikely to occur while running because the fuel, unless the engine is running obviously poor, will combust before it blows beyond the rings - therefore is most likely happening while the engine is at rest. 3. due to the repeated, short trips of the bike, the probable slight fuel leak into the crankcase does not 'vaporize' off as effectively as in an engine that gets more significant mileage on a regular basis. I have no doubt that bad rings or valves may produce the same results. I just can't imagine a Triumph twin would likely display such a condition until very late in the engine's life cycle.
