Wade My kids and I got into karting and somehow we ended up with a bunch of karts. We have 2 moto shifters, 1 4 stroke shifter, 3 clones, 1 Briggs World Formula 1 Aixro Rotary. and 3 Rotax.
I like to work on my own stuff but reliabilty is more important. I’ve found the Rotax to be the most reliable and overall the cheapest to run. Ours are in the 30-40 hour range and I’ve never done anything other than routine maintenance and that you can do yourself. You just can’t pull the head or split the case. I’m told that around 50 hours or so they need a top end and the bottom checked which seems to run $500 – $700. They’re so popular around here I’ve got lots of choices to get the work done plus parts are everywhere and the knowledge base is huge. They run a balance shaft so they’re smooth. They only require 93 octane we use non ethanol pump 93 @ $4.00 per gallon. The jetting can be a little tricky but no big deal. All and all they’re a good ride and IMO the best choice for a first kart.