welcome! i have a bike that looks alot like that, its a 1977xr75
anyways, the xl/xr's are great bikes, bulletproof. since you have no experience i would suggest buying it, or you can just go straight for a 125 2 stroke, but $100, even i wouldnt pass that up and im cheap and already own a bike twice as powerful! since you already know how to work on them, i think you would do great as a bike rider. nice bike btw!