Well, that helps explain the price. The downside of getting that “great deal” on the front end is there’s a ton of work on the back end.
You’re about to teach yourself swimming by jumping into the deep end of the pool–a kart fast enough to challenge a pro driver’s skills and an odd-duck motor that nobody else runs and will be able to help you with. If I were you I’d seriously think of selling the motor on ebay to somebody who wants it for an old Aprilla 125 and converting the kart to a Briggs LO206 or, if that seems to slow, a KT100 or TaG package (I’m assuming a spec Honda or ICC shifter motor would cost way more than you’d want to spend).
I say this as someone who started in a similar position and almost walked away from karting on more than one occasion simply from being frustrated and overwhelmed. And I was running a modified Honda that I could get all kinds of track-side help/support for.
I think 90% of the people I see in your/our position quit because they started out with too much kart that required too much work. 50% of them finally got their shifter in running condition, took it to the track once, said “holy shi*t” ’cause the thing was way more scary fast than they had even imagined, and never came back. I’d see the kart on Craiglist a few months later. Heck, that’s what happened to the guy I sold my old shifter to. I’ve seen in on Craigs twice in the past two years.
On the other hand, you could step in and be awesome. I’ve seen that too. Have fun.