2024 YZ250 Linear Power

HITLIS power valve

https://productivepowerllc.com/products/hitlisyz250

DRT head dome A or B

https://www.berad-products.com/products/drt-cylinder-head-yamaha-yz250x…

I did a few mods to my 23, one being an Athena 300 kit.

A fww, boysen reed block, hitliss and retarded the timing a few degrees.

I ride tight single track, more on the hard enduro side.

Hitliss will draw out the power some and soften the hit some, but  you should try a timing adjustment first since it's free, then a fww...the next cheapest mod.

I made one modification to the pv that I like because it's adjustable, easy and cheap.

A bolt threaded into the top pv cover to limit flapper travel.

I picked up a 2nd cover, chesp off eBay, drilled and tapped it so the bolt sits directly over the pv flapper post.

Put a Hitliss on my son's '24 YZ250x.  Power seems more linear now that my '24 KTM 250xc.  

I am a longtime Yamaha fan boy and I must say, my 250xc is probably the best/funnest two stroke engine I've ever ridden, it's just all around great.

Make it smoother without neutering it:
Weighted Flywheel
FMF Gnarly pipe and a full size (non-shorty) silencer 
Playing with jetting and air mixture

I am a 2 stroke fan boy until the death... And its hard for me to type this but..... You could consider the KTM and pay extra to fix the suspension to your liking, or perhaps buy a 4 stroke bike. The Honda bikes are a good price right now. 

1 bad injury and none of this is worth it. (If you are older) 

I LOVE seeing this sort of thing!

Someone giving a bit of thought to  a problem, or, a Goal, and doing it!

I can only assume there are no mechanical drawbacks to such a thing - having absolutely buggerall insight to the YZ250 PV.

Heck, I'm that much of a goose / tinkerer, I'd make a WIngnut Bolt ( making sure of clearance from the frame / radiator &nbsp - just thread up and tack / red loctite say, a Stainless Wing nut to a say, button head bolt - so I'd only need the One tool going to the lock nut. I've that sort of set up with various Idle Screws / Air / Fuel screws on carbs for example - I can reach down and, by feel, have a positional reference without needing a visual confirmation.

I've heard / read that there is some sort of PV spring spacer that is either used / not used on the X variant of the YZ250 : that might be a very affordable thing to try? Buggered if I remember what it did to the X - my assumption is that it might have tamed things down a bit?

Decades ago, on my quite vicious Maico 320, I snaffled a PV top cap from an 86 250 we had in the workshop, which had a lovely  Alloy top cap, as against the 320s stamped steel one, and threaded it, to take a very fine threaded pre-load adjuster I made, to change the pre-load on the spring behind the Diaphragm. It was a great way to make the bike So Much More Rideable / Changeable. Then, I tried a variety of springs.

I own a 2026 YZ250. I previously had a 2024 KTM 300 SX and a while before that a 2021 KTM 250 SX. I’m curious if you could describe the power delivery you want besides "more linear" and "like the KTM".  Do you just want more low end torque or does it spin up too fast in a certain throttle range?

The YZ250 motor is easier to ride compared to the KTMs for me (intermediate vet moto only).  In your case, I would consider going back to a stock exhaust and probably remove the vforce too. Then start testing jetting to see if you can obtain the feel you are after or get it as close as possible. Once you have a baseline, then start adding parts to adjust the power delivery.

I think some guys throw parts on a YZ250 without a sense of direction then start chasing wheel spin or power and it becomes a cycle of adding more parts to counter the mods installed previously.

All the mods you did really increase the bottom end of that bike, except flywheel weight. I'd go back to stock reeds (or boyesen reeds in stock cage) and go with a longer silencer, I run the turbinecore 2 on mine and love it for track and trails, or powercore 2. Also, do the power valve mod to make the power more linear. https://www.thumpertalk.com/forums/topic/1264473-powervalve-mod-for-yz250/ Also consider a Apex head with XC dome, or a DRT head. 

You do not need the hitliss

Have you used the Hitlis or just basing the do not need off of assumptions/opinion?

As above bin off the shorty and go for a long silencer, the stock one is decent.

On my RM250 this is one of the most noticeable single changes you can make for power delivery and engine character

I have not used hitliss, but I have heard some negative reviews on it. People that have installed it say it does not allow the powervalve to complete open under full throttle. You can do the powervalve mod, or get the cisco spring https://slavensracing.com/shop/yamaha-power-valve-spring-by-ciscos-race-tuning/?srsltid=AfmBOoqxQ3T6AWhPJukD9cZmAlroWfDrsEu3VrtVHsEBgcBtpDwcPN1b I have this in my bike and really like it. Both of those options are a fraction of the cost of hitliss. If your really looking for the linear power hitliss supplies, your on the wrong bike. Get yourself a ktm 300 and call it good. JMO. 

I have an 18 with similar setup except stock reeds.  I was gonna adjust timing before doing anything else.  I also took a washer out of the pv governor assy. I’m not sure if that had much benefit.

On my 2016, I too wanted it more linear than punchy. Kept every thing stock except I added a flywheel weight. That was the game changer for me. Still didn't stop my arm pump though lol 🤦‍♂️