My answer would have to be yes. I’m currently running a 2000 Easykart that I bought 4 months ago. It had very little use before I got it, or maybe it was just repainted or something. Since I bought it, I’ve been running with no lead on it on the same set of tires I bought the kart with and I was able to run with many guys at the track who have brand new karts. This weekend there at my local track, the spring series started and I had to make weight. We slapped on 50 lbs of weight and a new set of MG Yellows and hit the track in the TaG Sr class. I was able to qualify 3rd and finish 5th keeping up the pace with 3rd and 4th for most of the race until I tired out. An old chassis can definitely be competitive at the lower levels, but I can’t comment on whether it could be at higher levels.
