I have a 50, and I always casually wondered what the hole in the casting on the left and below the battery box would be for. There is no matching hole on the right side. I few weeks ago I had to replace the old battery, and while I was at it I replaced the old ground cable. The casting hole is in a perfect spot to run the ground cable out of the battery box and connect to one of the bolts that held the cylinder storage bracket. I haven't spent enough time around a 60 to know if it also has this hole in the casting.