not uncommon to have leaky petcock which continuously drip petrol into carbs. Then carbs with non-sealing float-valves just drip that petrol down intake-tracts into cylinders. Which then drips past rings over time and into crank case.
This happened on my 2009 Ninja 250 and caused stripping of starter ring-gear. Also happened to '85 VF500 parts-bike I got dirt cheap because engine was "seized". When I opened oil-filler cap, over gallon of oil+petrol mixture gushed out! Fixed petcock and carbs on that bike, which ran perfectly fine afterwards. Ended up giving that one to my brother.
|