The maintenance schedule will not be anywhere near as intense for a 2-stroke when compared to a 4. The top end will probably be the biggest hit on your wallet. Expect to do this every year or two (a lot more if you get into racing with it). People on here will say stuff to the effect like, you have to waste time measuring the oil to mix in with the gas. If you think about it, as much as you're changing the oil on your racing 4 stroke like maintenance requires, you'll be dumping every 2-3 rides almost the equivalent of what I'm mixing in. Use a good synthetic oil for whatever bike you choose (my personal favorite is klotz, but there's a lot of good stuff out there). Of the 3 bikes you listed the YZ is the best bet. Honda's CR250 is no longer in production and had weird jetting issues. The KTM SX is super light but does not have the power spread of the Yamaha or it's spot-on suspension. Is the new bike going to be used for trail or MX track? The KTM 250 XC would be a better bet if you plan on riding woods.

" Whic ….. h dirt bike do I recommend? "

The one that your Mommy and Daddy will buy you.

Ask them for the cheque book first.

I'd try to get him down to 800. but I would look for a 125 instead. you'll grow out of a 80 faster

I think you should look for something in the 250cc range, good power, balanced. And you can touch the ground….j/k Try the 250, RM250 from Suzuki is nice

To shift the gears on a motorcycle there is something important you should learn from the service manual and that is just exactly how many gears your bike has. Most bikes have either 4 or 5 gears. Modern Sports Bikes have 6 gears.

First put the bike in neutral, it is half way in between 1st and 2nd gear. Squeeze the clutch ( found on left handle bar) before trying to shift. You will know you are in neutral if a green light is showing on your gauges or if the bike rolls freely with the clutch out. Once in neutral you can start the bike, but keep the clutch in. According to your bikes shift pattern (Standard or GP Shift) you then shift into 1st gear by pushing the shift pedal up or down. Slowly let out the clutch while simultaneously increasing your RPM's with the throttle. The bike should start moving forward and as it does, release the clutch completely, but stay on the throttle. Once the bike is moving you can roll on the throttle to increase speed. As your RPM's increase you will need to shift into a higher gear; to do this you will need to squeeze the clutch in again. Then according to your bikes shift pattern, go to the next highest gear. Now release the clutch and roll on the throttle. To down shift you squeeze the clutch and shift to the next lowest gear, release the clutch. Be sure to match your RPM's to the wheel speed on a downshift or your rear tire can lock up resulting in a high-side.

There are currently two shift patterns on modern motorcycles, standard and gp. Standard shift is well…standard, it will be found on most motorcyles. GP shift refers to the shift pattern used by professional racers. GP shift is reversed so that a rider does not have his foot under the shift pedal when needing to up-shift in a corner, it also makes for faster up-shifts. GP shift is primarily found on sports bikes and bikes intended for use on the track, but most sport bikes come with standard shift from the factory.

Shift patterns are set up as follows…

- Standard Shift (starting from neutral):

First gear is down 1

Neutral is up one and it is indicated by a green light on your bikes gauges. If you are not sure you are in Neutral ~ it is the only time when your bike will freely roll backwards when the clutch is not engaged.

Gears 2 ~ 4/5/6 are all up.

- GP or Reverse Shift (starting from neutral):

First gear is up 1

Neutral is down 1 and will likewise be indicated by a green light on your gauges.

Gear 2-6 are all down

Shifting gears on a motorcycle may seem awkward at first, but try it a few times in your garage or drive way with the bike off. Roll on the the throttle and practice using the clutch to shift up and down. If while riding you start going to fast or you feel as if you are not in control, pull in the clutch to disengage the engine from moving the rear wheel and apply brakes accordingly. Within a short time shifting through the gears will be second nature.

Agree with him, buy a larger one, and maby he will pay for a little of it after he rides it a 125cc-250cc is good nothing more

Try a 250, if you're responsible enough to not kill yourself at first, it should have enough power to keep you happy for the long run.

You looking to ride on trails or on a track.

There are 2 kinds of engines.
2 stoke (not sure if they are sold new anymore)
4 stroke.

A 2 stoke 125 has the same power as a 4 stroke 250 – basically.
All 2 strokes are on the way out.

So assuming you will only look at a 4 stroke – maybe a 250 or less would be ok for you. You have to find out the stand over seat height if looking at used bikes…and make sure you can reach the ground.
A 125 4 stroke would be best to learn on but you will outgrow it in a couple years….not from size but from power – you will want more proably in a few yrs.
Buy a used bike for your first one – then after you learn and get better then get a nicer bike.
Dont forget the helmet and be safe.

Well, you are going to probably have to decide what kind of riding you like to do. Starting off on a dirt bike will have set you up well, for handling any emergency manevers you might need on a ligh weight street bike. If you liked playing in the dirt, something on the sporty side is probably going to appeal to you more than a cruiser, but that just depends on you.

I'd start out on something like a used Suzuki GS500, or a Kawasaki Ninja 500. They are great to get the hang of street riding on. Take a motorcycle safety course, just to get use to the "rules" of the road if nothing else.

You can find a nice used Honda CRF250R from about 2,000-6,000 depending on the year. I'm the same height and weight as you and the 250 would be a great bike to grow into. And there is no such thing as a CRF125, but there is a CR125.