theres a wire running around the engine with a id tag. You should also get a logbook with the kart. If this is missing they can be worth alot less so be carefull. itdepends on what you want tbh and what you pay to start off. My 2 mates just sold there 2002 tonykart Rotax max with loads of spares for £1200. Both karts were mint and very highly prepared