I have a 1978 Intramotor Verona Gloria, I'm pretty sure it has the Morin m1 engine now. Long story short I overfilled the oil and don't know where to start. It didn't run for long I shut it down as soon as I noticed but now it has a low knock coming from the engine and a high wine at high speed. Where to start the rebuild? And is there any bigger motors that would fit the mounts? Looking for cost effective route but still want to gain some power.