125's... Let's beat this dead horse!

Yes

Get a yz. It's been the same for years, parts are interchangable, cheap and super reliable.

You can't go wrong with a YZ .  The 97 YZ 125 I had was the best bike I've ever ridden regardless of size and they've only gotten better  . I've been out of it for awhile however.  The newest bike I've ridden was a 2003 KTM 250 SX which was a pile but I've had several 125s including a 98 CR and 99 KX .

Go the Yami for the reasons above, it’s a well understood horse by now and even if you’re one or two ponies short of a KTM, it doesn’t matter when you’re riding for fun.

The 03 Honda handled well you say? Slow bikes usually do 😂

The austrian 125 makes WAY more peak HP but it also is all up top.  If you cant ride it that way you are better off with the YZ in my opinion.  I just rode both back to back last weekend and that yamaha suspension is just so hard to ignore.  I rode a bike that was setup for 120 lb rider and im 180 but it still soaked up everything.  I wouldn't have wanted to come up short or overjump anything but i did overjump a few times slightly and was waiting for my wrists to explode but it never happened.  The 22 SX is just so much faster but midrange is so good on the YZ and the jetting is so good.  Toss up and choose based on yourself

I just prefer the chassis, suspension and power delivery of the YZ. It for sure seems to give up a decent amount on top to a new KTM but to me it's easier to ride. And I don't know if it's partially due to the motor or what but I think the YZ darts around a little easier. Plus like mentioned above, the parts cover so many years, so everything is figured out and plenty of parts out there. I have a '19 and still love playing around on it. 

How bad is the CR and KX? watch Jimmy D, Carson Brown or JS on one of those bikes and tell me that a stock-ish bike will hold you back.

And no, your 03 was not a dog compared to the 96, that's in your mind. the cr125's did not get slower compared to the older bikes, but the other brands got faster.

When it comes to the engine, KTM is hard to beat but i would go with the yz since i don't like bikes that are hold togeather with wood-screws.

The YZ was updated for '22 and I have nothing but good to say about mine. It's still carbureted (although rich in stock form), and the top end is supposedly stronger than '21. 

Get a 04 cr125 the chassis is a refined 02,03. Beefier swingarm , small frame updates, valving updated & it’s good, forks r inner honed 1st model to hv that. Engine deck, port , carb bore & it’s the biggest improvement of any engine.  Early hit then a strong & very long mid that goes into the ovr rev. Best midrange engine ever. Short shift & it will keep pulling or let it rev to the moon. Best sounding engine also.  Chances r slim to none of getting a DBP tho.

The 04 used a servomotor RC valve, 2002-2003 and 2005-2007 used a governor RC valve, good luck finding 04 parts parts!

The only reason I probably wouldn't get a KX, CR or RM is parts availability. I had an 02 RM125 and I did love it. It certainly had it's own character compared to the YZs that I've mostly had over the years. Same with the CR and KX, which have their good points etc. But I if I was going to buy a 125 to ride frequently, I'd stick with a YZ or KTM just for parts availability etc. There is nothing about those other bikes that are better overall machines to bother with potential hassle in getting parts, in my opinion. If you were building a project bike, just to have an ride or race occasionally, then by all means that is different. Just my opinion.

Everyone uses a rc car servo once the Honda servo craps. Using the hrc adjustment method it’s way better than a mechanical pv.

Having gone from 15 years of owning an 06 yz125 I had Eric gorr do a 144 to it after 6 months of owning it. I got the bike summer of 05. Bike before that was an 04 kx125 and before that an 02 yz125. And a 01 cr125. At the time I got my 06 yz's my friend got some 06 cr's. I'm now on a 21 150sx for my small bore. 

No doubt the yz is a solid choice but I really enjoy my 21 150sx. Especially now that I have it sorted out. The ktm once I fixed the jetting it became a lot easier to ride off the bottom end. Suspension needed fixing not so much the fork. Rear spring is to light. 

The 150sx beats my yz144 my 144 was setup for more mid top end. Higher compression head I ran on 110 race gas. It was no slouch but my ktm still beats it. Still has a little more and it does it on pump gas. 

The ktm handles great it's better at the inside lines vs the yz. It takes less body English to toss the ktm into the line. The ktm does feel a little bigger ergo wise. 

This could be because my 06 had basically the 02 ergo's. Which still has a bit of that 90's. Sitting in a pocket around the gas tank feel. Where the ktm feels a little taller because it has more modern sit on top of bike feel. Which the new 22 yz's went towards. 

06 yz125 vs 06 cr125 - yz wins only on its easier to use engine power. And it's 6 speed. The cr good engine better modded. But it has old school 125 style power. No much to little bottom end strong mid hit into a long top end pull. 

Stock jetting sucks it benefitted from the pwk swap a lot. It's limitations where the 5 speed occasionally. Where your in 5th gear ran out of power on the top end. Where the bike starts to bind up. You start wishing for that 6th gear. So you can upshift and get that pull back and unbind the bike. But instead you end up just having to scream it. 

I'd skip owning a cr now unless you really want a honda. Aftermarket support is okay at best. Honda has been discontinued many parts for them so finding new just became more difficult. 

The 04 kx125 fun bike decent power it's limitations. Suspension odd engine character where it sometimes under a load would rev up lil slower than you'd like it to. 

For some this maybe a positive or negative. Shortest 125 seat height wise I've ridden also the lowest ground clearance. You will notice this in deep ruts or off chambers. Where your feet will touch the ground. This was also a plus at times the compact size you could really throw it into corners and whip it off jumps. 

Aftermarket parts are like non existent for it now nearly. Parts hard to come by should you break something. It is also like 8 pounds heavier than the 06 yz current carb'd ktm's and cr's. Back in 04 I was like the only one with a kx125 usually. 

The old steel frame yz's are good loved my 02. Didn't really mind the 5 speed transmission. After my 01 cr125 it felt like a rocket ship. Good bikes power still pretty close to the 06+

But they to are getting old and some aftermarket stuff is drying up for them now as well. Even Yamaha has discontinued parts for them. The steelie frame will be 8 pounds heavier as well over the aluminum. 

Walk right past the Suzuki's RM's have to many 1 year parts on the top ends. Different power valves nearly every year Different cylinders. 

I don't know much about the other brands.  I love my 2005 Yz125 upgraded to SSS forks and an '09 shock.

The 2022+ is an upgrade, but I have no complaints whatsoever about mine.

The frame hasn't changed since 2005, so the newer plastics can transform the look all the way to 2021, and I've heard up to the 2023 with the exception of the number plate.  How the plate mounts to the triple clamps changed somewhere around 2008.

If you want factory plastics, you'll need to replace the air box as well, but other manufacturers sell restyle kits that use the old airbox.

Its gonna be about condition in an older bike.  Yz 2005 up.  No big changes since 2006 when it got sss forks.

150sx, all day long!

May want to read the specs on the 22/23 YZ.

Nothing better than a day on the track with a 125. Puts you in a good mood for several days or even weeks. 

That doesn't help with sourcing the shaft, flappers or cables...

I bought a 2007 CR125 new and have over 500 hours on it.  Not sure why people never bring up how cheap Honda parts are compared to the other manufacturers.  It has been wonderful.  BUT - unfortunately Honda has just quit making parts for them.  Talking transmission gears, cases etc.  SUCKS.  Next bike will be a Yamaha.  

I have a 06 cr125. It does go flat on top but it dosent hold me back,just have to learn how to ride it and short shift it sometimes.For the average riders,this bike isint going to hold you back,only think holding you back is skill and letting off to early😂 my son has a 04 yz125 and I do like that motor alittle better….I like the handling and the ergos on the Honda much better. 

Your son's too big for his YZ125, time to transplant his engine into your frame!

I think I speak for all of vital on this one…would like to see a video of you ripping one of these fast cr125 to see if they are what you claim! I’ve had Honda 125’s in the past and unimpressed.

To answer the OP, I’d go with a new yz125 and lean the jetting way out on half c12. They run way rich stock but very good when jetted correctly.

My last 125 was an 81 CR125.

It was cool until you went fast. That sucked because I was riding off-road.

What I decided was, just let Jesus decide. 

I recently picked up a 2022 KTM 125 and have been loving it. I was a little worried being 195lbs on a 125 and not riding one for about 20 years, but so far I've been really impressed. My other bike is a 22 KTM 250 SX, so the chassis feels very similar between the two bikes, although the 125 handles a little better overall. I'm partial to the KTMs, but honestly don't think you could go wrong with any of the newer 125s.