Well there are a few variations on "pit bikes" but here goes with the basics. At off road races down here in the Dist 38 area, pitbikes are/were just that, little bikes for getting around in the pits between races or when getting ready for a race and your main machine was getting worked on to get ready for the race. They were anything from old Honda Z50's to little XR50's, to Yamaha PW50's etc. These days they are selling so-called "pit bikes" at Kragens and places like that that are made in China, with up to 110cc engines and questionable reliability. More little mini-bikes than anything you could use on a regular basis, they are copies of Japanese bikes in all respect except the reliabilty, not really suitable for long term use in the desert, and not really meant for the street, they are just parking lot toys for semi-grownups. The shocks arent really suitable for offroad, they just have big springs to look like they are, so if you are thinking of buying one for something like that save your money and buy a real offroad bike that you can learn on for reasonably cheap like an older XR200 or CR125. At least they have the underpinnings of a real machine on them.

My son was about 2 1/2 when he showed intersted in anything with 2 wheels. he was riding a bicycle by 2 1/2 without training wheels and a motorcycle by the time he was 4….

make sure he can hold the bike up by himself, that is the key factor…

honestly, 2 years old is a bit young in my opinion!!! start him out on a bicycle, when he has some balance on that, and can hold a motorcycle up on his own, give him a try…

balance is the issue, but make sure to put him in all the proper safety gear!!!

Get him a small 4 wheeler and do not forget to get him a helmet.

Most sites that sell online have gear for small kids. Btosports.com has a range and also a sizing chart that would be helpful.

Make sure you spend the money on a pair of proper mx boots as I have seen some very nasty burns from kids not wearing the right gear. They only have to drop the bike and be pinned under it.

Trek makes a KDR bike. It has 24" wheels, give it a try.

These are very respectable wheels and I mean all their products and yes you can swap out.

DO NOT get a Mountain bike if you wish to do a lot of jumping. A BMX 20" wheel bike is better. Of course, you can jump a Mtn Bike (MB) but you are risking quite a bit of damage. The larger wheels of a MB are more at risk for damage. Plus the gear system will give your problems. Stuff like "chain slap" or just the chain coming off from the impact of landing.Worse damaging derailleurs and such during any crashes.
Unless your are a very experienced rider Don't plan on using a MB for a "jump bike", you'll spend more $$$ fixing it than what the bike costs.
I've seen this kind of thing happen before when I worked at a bike shop. Use a MB for cross county off road riding and get yourself a BMX 20" wheel bike, with lots of spokes, for jumping. It will be cheaper in the long run.

Plus as far as MB's go I like good steel frames, full Cromoly.
They're cheaper and steel is twice as strong as anything else in your price range. Plus a steel frame MB will usually always have better parts on it than a aluminum frame MB. And for jumping wide rims for either BMX or MB's.

Finally. Change your handle bar to a very strong heat treated one, even on a new bike. DON"T be cheap here! If that thing brakes on landing… OUCH! … and prepare for major dentist bills. Lots of jumping, change handlebar every year.

Just buy different tires that have dirt tread on them. i use my "park" wheels on dirt doesnt make to much difference i find.

Well since you said your not that graceful..i would recommend getting a 4 wheeler first…dirt bikes arent hard to drive..obviously 4 wheels are easier than 2 though

Sure it's possible, with engine mods and parts, suspension mods and parts, nitride coatings, aftermarket wheels hubs spokes, tripleclamps, graphix, steering stabilizer, ignition mods , aftermarket exhaust aftermarket air box/filter mods, complete titanium bolt set, shark fin, aftermarket brake lines , wave rotors, engine covers/gaurds and engine plugs, blah blah blah ……..etc, the list goes on. if you are willing to spend the money, there is someone out there willing to sell you something for your bike. they talked about jeremy mcgraths bike last year at the xgames and said he had 100,000 into it. (what parts exactly , i don't know). there is an aftermarket , or upgradeable replacement part for every part on your bike, so if you have the cash , go for it, oh , and send me a pic when it's done. have fun and be safe.