Win more than 50 events with your Signature Car
Go to "Quick Race Weekend" then to "Glencairn West" (it's 0,45 km // 0,28 Miles long). So this track helped me with the "Home Field Advantage" Achievement, too. Take the "125cc Shifter Kart". After one round go back to the menu and repeat this (for one round I needed about 28 seconds). After 51 times you get this Achievement.