Check this out. it's very expensive, but also powerful and light. it's also a four stroke!! It's not a mazda but it's a rotary with 48 HP in a small box. I'd bet it could run direct drive as well. roatry's rev like mad.
http://www.cometkartsales.com/store/engine/aixro.htm
this site say's it weighs 32 lbs!!!
http://www.zercustoms.com/news/RENNtech-Aixro-XR50-kart-engine.html
http://www.cometkartsales.com/store/engine/aixro.htm
this site say's it weighs 32 lbs!!!
http://www.zercustoms.com/news/RENNtech-Aixro-XR50-kart-engine.html