Best YZ250F from 2014-Current..

I had a 14 and only thing wrong with it was no electric start.  

From  MXA:  Q: HOW MUCH DOES THE 2017 YZ250F WEIGH? A: At 222 pounds, the Yamaha is one pound heavier than last year.Dec 5, 2016.  

The 2024 model is 231 lbs.  I personally like the 17 and 18 Yamaha 250f over any of the newer YZ250F's.

2018 owner here. Bought the bike brand new in August of ‘18. Just a fuzz under 60hrs on it now with zero issues or complaints. The chassis feels nice and stable in the chops and the stock suspension feels great. Obviously made some clicker adjustments but I didn’t feel the need to send it out as I was happy with how it was. I love this engine. Really nice bottom/mid range power. Lacks a little on top compared to my buddy’s ‘20 that he has but his doesn’t have the bottom end mine does. Solid bike!

I like the 2013s a lot with a few mods.

I did spin a few laps on a 2013 one time. All stock except for some carb work and that chassis felt great too. The 14-18 engine was a jump in power tho

Love my 2014 yz250f.   Great power everywhere for a smaller bike.  Too cheap to upgrade bikes.  Had a cam lookup in the head 6 years ago so added a GYTR head , , hicomp piston and cams.  This year broke the rod bearing.  Still decided I was better to fix it then get a new bike.  My math skills might not be for everyone.

My 15 was a piece of Sh. Rod broke at 60 ish hrs. Zero topend. Over rated bike imo

The 10-13 was a great chassis. Once I modded the engine (gytr head, Air4orce boot etc) that was a great bike. The 14 was amazing. Still 1 of my favorite bikes, even bone stock. Just needed to dial the suspension and get the right sag, so the front didn't skate. I personally don't feel like the 14 is faster than the 21+. They run different but still have a lot of the same characteristics. I think for local racing, a 14+ is plenty competitive in most classes. It's just a matter of keeping it fresh. I still have my 21. Actually considering adding the TD dual injector kit rather than get a '24. I just dont want to start over on the new chassis, when I'm dialed in on this one. Knowing that I could probably still be happy if I had my '14, gives me some relief in keeping the 21, rather than getting a 24 right now. But if I had a bunch of hrs on mine and just wanted a fresh start, I'd get a 24 without hesitation.

I love my 2017. Granted , its the only 4T ive ever owned. Last bike was a 1999 RM125. Had been 20 years when i got this one back in Jan 2023. Got a buddy with a stock 2017 for sale in NC. Has 35 hours and is mint. PM me if you want his info. 

2014: 40.61 HP @ 12,100 rpm; 20.28 TQ

2024: 39.2 HP @ 13,000 rpm; 17.9 TQ @ 10,200 rpm

That is comparing wet (Yamaha measurement) and dry weight (MXA measurement). The 2024 is around 225 lbs dry.

I rode a 2017 with a full exhaust and mapping to suit back to back with a 2022 and I way preferred the 2017. 

Totally bias info here but im saying 2021 
I have 2 of them and its by far the best bike I personally have ever owned 
the bike is super forgiving and makes up for a lot of dumb mistakes on the racetrack 
Its gotten me out of a lot of trouble 
Here is a shot from etown with my buddys YZ250 2 stroke too 

2024 is mappable from your phone though, I'd like to see people Dyno them with the different maps and see how they run. I know from the factory they're not tuned for maximum power. 

Don’t sell yourself short.

You’re only 900 years off!

ha ha bad math!!

I bought my 2015 new and it's a awesome bike with a oversized front rotor and braided brake line.

No reason to get rid of it. Only 20 hours on it 😊

I forget where I read it (or possibly heard on a pod) but supposedly no matter what map you try with the app, it will not actually make any more power. It just changes the characteristics. And either way, whether it's the 14-18 or 19+ getting a Vortex really wakes the bikes up even more, so on a 14-18 I would for sure do that, if you don't have the handheld tool.

Also, direct comparisons from different dynos are meaningless

Agreed. I had a 16 yz250f. It was ok. Went to a 17 crf450 which was the worst bike I have ever ridden (which I didn’t realize at the time). Spent a lot of money trying to sort the suspension and chassis. Got a 21 yz250f and everything changed for me. More comfortable than I have ever been. Faster than I was in my early 30’s (40 now). The bike has never done anything unexpected. 155lb vet a/b. I’m going to buy a new 24 but will keep the 21. 

That is awesome. I meant to also say, the Cycra shrouds really bring the bike more in line with the feel of the 19. So that is 1 big upgrade right off the bat, as I'm sure you know already. And otherwise like most have mentioned,  that 14-18 gen is pretty much as competitive as the new ones. I was helping with an AX team a few years ago and 1 of the mechanics still has 1 of those YZFs (maybe a 15) that we were using. It's built up nicely and still fresh. I would absolutely have no problems having that as my main bike. And even though my personal 14 wasn't modded too much, I could be happy if I still had that one too. Any of the 14 and up are worth keeping or building.

I'd vote for 17-18.  I had this bike since them came out and the motor was a big improvement over my 14.  I then bought a 19 and it lost all it's low to mid and I felt was slower.  Full discaimer I race offroad.  On the track where I spent more time in the upper revs the 19 was fine.

Also.  The bike got considerably smaller in the seating area in 19 and I didn't like it at all.  Sold it and went back to a 17.