Danger is what makes it fun!
True but safety is more important.
You are correct in saying that this will be a dangerous gokart. It is all home made, scratch built, and built with getting it done in mind over quality. I do plan to wear a helmet. I do still intend to spend as little as possible on it so I will not be buying a frame. If I had a brand new 8hp engine or something like that, I'd put more care and money into the quality department but for now, it is just some experimental fun and I just want it to move decently. With me and a 3hp engine, I don't think the two of us will be going anywhere too fast but maybe I'll surprise myself.
The rear is the frame from the lawnmower. The frame will be primarily aluminum C channel (1x3x1/8 I think) bolted together.
May I ask what exactly happened to your neighbor's frame/kart to cause the accident?
Also I have a safety question. It would be a good idea to have a seat belt right? There isn't any reason not to have one (like on motorcyles) is there?