the parameters

The initial plan was to spend as little as possible on the 'Motorkart'. The search for an inexpensive kart and motorcycle started. My original plans, influenced by a knowledgeable friend, included a 1-cylinder 450cc motor from a dirt bike. It makes a good ~50hp and weighs relatively little compared to other motorcycle engines. But, I decided that the gear ratios were really wrong for a go kart and started searching for an engine/tranny setup from a Kawasaki Ninja 500. The usual ex500 has an inline 2-cylinder that makes decent power and isn't too hard to source.

A few people told me go the 4-cylinder route. At first I was a bit hesitant due to the extensive changes I'd have to make to the frame of the vehicle. I eventually decided that the usual 4-cyl is cheaper, more powerful and pretty well suited for the kart.