I had to weld up a crack in the clutch cover on mine after a tumble, and also a hole in the rear of the engine after drilling the swingarm bolt hole and narrowing that part of the motor to fit in my 250 frame. after 30 years of oil sitting in there, that aluminum really soaked it up. I spent a long time cleaning and wire brushing and I was still burning oil. if you are a good welder it may be no issue. all I can say is clean the hell out of it and burn the oil out of the area with your arc then re clean and repeat before you really get a puddle going. aluminum is a pain as it is so make sure its clean. good luck its doable just tedious.