Originally Posted by Pops of the desert
Having ridden nearly 50 years on many bikes, started three children and several grand children in this wonderful sport. I would suggest starting no larger than a 250cc bike. No matter what you buy you will either hate it and quit riding or love it and want a better steed within a year. So a used 250cc dirt bike should get you going, if you go to big you will be done riding in a year. Pops
The advice to start out small and go from there, or play it safe with a 250 and upgrade later, should be taken with a grain of salt. If you're a moron who is going to hop on a bike with reckless abandon and gun the thing without feeling out the clutch/gas and get to know the actual power of the bike before flying down the road, then by all means you should start with a 250 and work your way up. Any responsible rider just starting out would be more than fine on a 650. This is coming from someone who learned on a 250 and was brow-beaten into thinking a 650 was "waaaaaay too much bike" for a first bike, and then got on a 650, rode responsibly, and realized that advice just didn't apply at all.