Graziano Bianchi is a track mechanic with decades of experience. He currently works for BirelART and is the right person to turn to for an overview of the key steps to go through to prep your kart after you take it off the van (or car...) and before you fire up your engine on track.
The first thing to do is inspect and tighten up all bolts: hubs, steering wheel, axle bearing keyways, and anything that is safety-related. Five minutes and you’re done. After the first lap on track, do another run-through; then do five break-in laps and follow up with a third inspection. At this point, also check your convergence, adding discs.
Mount the engine on the chassis and align the gear wheel and sprocket. To adjust chain tension, work in steps: first tighten the front bracket, which pulls the chain, then tighten the rear one, which losens it up.
Remember: it’s better to keep the chain slightly lose rather than pulling it too tight, or you’ll run risk snapping it or, worse, bending the crankshaft.
First of all, you need to fill the rad up: connect the hoses and pour water into it, keeping the kart tilted to the side to avoid any accumulation of air bubbles. Some engines come with an air release valve, but lifting the kart up on the rad side will do the trick just as well. When you’re done, let the engine roar for two minutes on the trolley, then top off the rad.