2027 Yamaha YZ250F, All-New Engine

6/4/2026 4:38am

Yam releasing this a day after the KX327 news, and receiving about 1% as much interest...

4
FGR01
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Fantasy
6/4/2026 5:43am
AH387 wrote:
This is the one that I have been waiting for and not going to lie, I've been a little bit worried about. I have been a...

This is the one that I have been waiting for and not going to lie, I've been a little bit worried about. I have been a big fan of the YZ250F style of power, especially since '14. And it's really the only 250F that I keep going back to. So with the sound regs in place and having to choke it back, I was curious how they would handle this. And now with the change in the head, along with the bore/stroke change, I feel like it may make more peak hp but run more like a KTM and not have the instant response and recovery that gave it the character it's been known for. So I'll be very curious how this goes. I really don't want smooth and linear, with all the power up top, on a 250F. I like it very lively and fast revving, even if I need quicker upshifts. Plus, the ability to sometimes pull a taller gear in turns was always a plus. Maybe it'll all still be good but I'm not so sure. I also noticed that it gained like 5lbs.

Just like the 26 YZ450, everyone will be swapping out the intake funnel, muffler, and ECU to get it back where it belongs.  No worries.  Have to undo all these ridiculous sound measures that are the stock bike for some unknown reason because of Pro/FIM sound limits.

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AH387
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6/4/2026 7:14am
FGR01 wrote:
Just like the 26 YZ450, everyone will be swapping out the intake funnel, muffler, and ECU to get it back where it belongs.  No worries.  Have...

Just like the 26 YZ450, everyone will be swapping out the intake funnel, muffler, and ECU to get it back where it belongs.  No worries.  Have to undo all these ridiculous sound measures that are the stock bike for some unknown reason because of Pro/FIM sound limits.

Yes that is very true. And to some extent, a lot of vet guys on 250Fs are doing an ECU and exhaust etc anyways, so it's just a few more things that will need attention (airbox and funnel etc.) That being said, it's not so much the amount of power, that I am worried about. I think it's more that I'm assuming as a stock bike, Yamaha maybe didn't think they could get the air velocity any longer, to make it run like the prior engine. So they decided to shift to the new head style and make it more of a top end screamer, like the KTM. So I will be a bit bummed if that is the case, because I really do love the character and power profile of the older bikes (especially the 21-23.) And as I mentioned, I think that response, recovery and ability to pull a higher gear was the allure of that bike. So if that goes away, then I may start swinging back towards thinking about a 450 again. I'm sure it'll still be a great bike, but I think the YZ250F had it's own little niche market of vet guys who liked that unique power and now it sort of seems like it may be more in line with a "typical 250F" power profile.

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Timo
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6/4/2026 3:07pm
AH387 wrote:
This is the one that I have been waiting for and not going to lie, I've been a little bit worried about. I have been a...

This is the one that I have been waiting for and not going to lie, I've been a little bit worried about. I have been a big fan of the YZ250F style of power, especially since '14. And it's really the only 250F that I keep going back to. So with the sound regs in place and having to choke it back, I was curious how they would handle this. And now with the change in the head, along with the bore/stroke change, I feel like it may make more peak hp but run more like a KTM and not have the instant response and recovery that gave it the character it's been known for. So I'll be very curious how this goes. I really don't want smooth and linear, with all the power up top, on a 250F. I like it very lively and fast revving, even if I need quicker upshifts. Plus, the ability to sometimes pull a taller gear in turns was always a plus. Maybe it'll all still be good but I'm not so sure. I also noticed that it gained like 5lbs.

Timo wrote:

The five pounds is interesting, maybe from sound damping and beefing up the transmission? 

Not to mention an all-steel clutch basket and now another master cylinder plus a slave cylinder, hose and fluid to replace a cable.

It all adds up.

The 450 lost over a pound on the new style clutch with the steel basket. 

Pop Shmoke
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6/4/2026 3:35pm

I’m curious too why the pic shows shim under bucket when the release says finger followers. Did they really only do it on one side or is that the wrong pic? Why would they show a cutout of that side vs the side with the updated valvetrain? 

6/4/2026 5:03pm Edited Date/Time 6/4/2026 5:04pm
Pop Shmoke wrote:
I’m curious too why the pic shows shim under bucket when the release says finger followers. Did they really only do it on one side or...

I’m curious too why the pic shows shim under bucket when the release says finger followers. Did they really only do it on one side or is that the wrong pic? Why would they show a cutout of that side vs the side with the updated valvetrain? 

Here's a motion graphic that shows the intake side from the Yamaha site:

https://www.yamahamotorsports.com/media/video/MY27_YZ250_Hero.mp4

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MikeID
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6/6/2026 10:49am

I’m curious to see the reviews that compare the ‘27 to the ‘26.  I really like this gen motor.  How is the feel of the hydro clutch?  Is the change to the brakes noticeable?  Is bottom end the same or power shifted up in the rev range?

Village Idiot
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17 hours ago
Timo wrote:

The five pounds is interesting, maybe from sound damping and beefing up the transmission? 

Not to mention an all-steel clutch basket and now another master cylinder plus a slave cylinder, hose and fluid to replace a cable.

It all adds up.

Timo wrote:

The 450 lost over a pound on the new style clutch with the steel basket. 

The new clutch assembly with the steel basket was one pound lighter than the old assembly with the aluminum one or the bike was one pound lighter overall and had the new clutch assembly?  🤔

Timo
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17 hours ago
The new clutch assembly with the steel basket was one pound lighter than the old assembly with the aluminum one or the bike was one pound...

The new clutch assembly with the steel basket was one pound lighter than the old assembly with the aluminum one or the bike was one pound lighter overall and had the new clutch assembly?  🤔

The clutch lost a pound, bike lost 5 pounds overall.

Village Idiot
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15 hours ago
The new clutch assembly with the steel basket was one pound lighter than the old assembly with the aluminum one or the bike was one pound...

The new clutch assembly with the steel basket was one pound lighter than the old assembly with the aluminum one or the bike was one pound lighter overall and had the new clutch assembly?  🤔

Timo wrote:

The clutch lost a pound, bike lost 5 pounds overall.

Then I'd attribute it to the redesign and not the material (obviously).

13 hours ago
ksithumper wrote:

Yam releasing this a day after the KX327 news, and receiving about 1% as much interest...

Yamaha is suffering from success. Everyone knows how good the YZ250f is already.

Village Idiot
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13 hours ago
ksithumper wrote:

Yam releasing this a day after the KX327 news, and receiving about 1% as much interest...

Yamaha is suffering from success. Everyone knows how good the YZ250f is already.

"Shiny Things" syndrome.

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