Here's one I saved to email from a loving man so helpful on and off the track, and most importantly....Spirtually....
Rhett Majors...............
The article I wrote was entitled "SteerRoids" and without looking at the article I would have to say passing depends alot on the scenario. There have been times on a wet slick bullring we passed on the outside in the cush like sprint cars. It takes a little courage but hey.....either go to the front or go the hospital!
In some scenarios on wide tracks or high bank track "diamond cutting" the corners is much faster too. If you watched the truck race on dirt a few guys were using this move.
But I'm going to guess you are probably on a one groove track and you don't have the option of moving around too much. If you are at the beginning of the race and you are running second stay directly behind him and be paitient (which means wait in a hurry) for two reasons. #1 If he's not that experienced he may get rattled easy and mess himself up without doing anything, or #2 you also have to drive behind you and know third place is thinking the same about you. If you really know how to "trail brake" get on his back bumper going into the corner and push him down into the corner BUT NOT down into the apex! Trail brake minutely just to pivot your kart to the bottom. If you don't you chance "wheelhopping" him and messing yourself up. The only thing you are looking for is a smidgen of a bobble in his kart to push him slightly up the groove and you head for the bottom of the apex to get the nose of your kart by him. You do NOT have to run over him and if it's done properly it should look like he over shot the corner. This is not dirty and if someone is faster than me I invite this kind of passing instead of the alternative.
Another alternative is to get as high on the groove going into the turn as possible and we are talking tiny increments here because you don't want to slip off the groove, then soften your corner speed slightly and drive it in the corner like your driving a pickup truck with something in the back you don't want to flip over (in other words be smooth on the wheel) pivot your kart sooner than his (early apex) and use the bank going downhill to make up time.
Last but not least: Most drivers do not know how far they can drift up to the wall or go down into the apex without hitting the barriers, but I can tell you that you can steer a Kart alot closer to something than it appears without hitting it. So, if they have tires marking off the apex you should have black marks on your side panels if necessary! but please use your head! Lol! Don't have your heart full of racing with an empty head! And have fun!
I'm washed up now and been retired for too long, but maybe the principals are the same.