Omg understeer was what I was fighting all day. Its a HUGE part or karting... The handling that is. They are pretty simple to work on, but it takes ALOT of practice to "get to know" your chassis and how to set itup for different track contiditions... front and wear track width, torsion bars, gearing, clutch engagement, carb mixture adjustment, tire pressure (1psi can be the difference between sliding all over the track and having the chassis handle like a dream) Axle stiffness, tire compounds, Weight distribution, Castor, camber, toe in/out. Everything youd find on a normall car and then some. The only thing is, is that these karts dont have any suspension, so the way the frame flexes is what determines how it will handle.
Jim