Thanks everyone. In the process of fixing the crack by the bearing hanger I found a crack just aft of the motor mount. I did stop drill holes and ground a V following the cracks. The two cracks were within an 8 inch section of frame. With a 40 horsepower engine with chain drive and a six speed trans...

Filler rod recommendations? I have ER80S02 and ER70S06.

I cleaned the area and it looks like a crack for sure. I'll stop drill it. Would a slight grind of the crack to create a slight V shape be of any use or just weld on top of the crack?

While cleaning and inspecting my Go Kart I think I found a crack next to the rear bearing hanger. I will clean the area to make sure it is a crack before trying to weld it up. I will weld in a gusset from the bearing hanger to the frame rail after I weld the crack. Any words of wisdom before I start...