83 – 1100 with 38k miles, first ride this spring …. Awsome! Ran like new, never missed a beat. Had to let it set outside one night uncovered and you guessed it, it rained. Started it up and whow it sounded like every part in the engine\tranny was going to come through the housings. Idles “OK”, but with a clunk here and there. When I start to throttle up it sounds bad, really bad, like a barrel full of rocks. What would make this change “overnight”. It doesn’t seem like anything mechanical would happen that quickly……….Any ideas?