hydra

hi, i've got an 85 ATC 110, its been sitting in my friends grandfathers house since 87, the thing is mint except it needs new tires and some carb work. Should i rebuild the carb or buy a new one (its leaking round the petcock and could use a new float). and secondly are there any engine upgrades, i.e. a 185 swap, as i could get one cheap, thanks and great site by the way