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Only $10 for all 2026 SX, MX, and SMX series.
Matrix concepts sells them on website.
One thing I've found with these is the countershaft seal bore doesn't have a stop. If it's installed too deep the the countershaft collar notches will cause a leak. I wish Yamaha would put a stop on the backside of that cover so you just push the seal in until it stops.
For anyone over 95kg I found backing off the high speed compression surprisingly helpful. I’m on quite a stiff spring and this gave it the much needed movement under hard acceleration.
6.3NM spring
LSC 15
HSC 1.875
R 7
Spring preload 5mm
Been riding the yz250 nearly all year, so I’m sad to say the 450 is going up for sale. Been fun getting it all set up and in retrospect the big two things for me were lowering the rear and getting the clutch hub sorted on the 2024.
If I knew then what I know now I’d probably make a lot less mods 😅
The Shop
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Luxon 4-Post Bar Mounts
$189.95 - $239.95
I know this is the YZ450F thread but I can't seem to find a 2025 YZ250F thread. I've run into a problem I haven't expected on my 250 while racing in ruts the other day.
I would enter the run and the bikes front end would ping pong around really bad inside the rut, I'm a prettry strong guy so I could ride it out a lot but it definitely zapped a lot of speed and confidence, if it wasn't ping ponging it kept trying to over steer and crawl out.
Ive tightened my steering bearing a lot already before riding this. I'm thinking of tightening it more to be closer to my 450. Could the over steer problem also be an example of the front suspension too soft. Its set up, valved and sprung to me already but might need some clicker adjustments.
Pin the throttle and dont fight it and it will flow through better.
Sounds like clicker adjustment is needed
Maybe somebody Can help me. I’m Running the GYTR Hydro Clutch and a twinwall Handlebar. I’m looking for a pair of handguards that Mount Directly the the brake and clutch masters, as the handlebar Space is completely Full. Does anyone know of anything from another bike that might fit?
I’ve tried KTM Stock ones, as the Brembo clutch master is the same, but I can’t make the bracket for the front brake fit.
Someone made some that bolted to the top triple clamp bolts if memory serves. Cycra maybe?
https://www.motosport.com/product/?code=SS-M-G-P-NA-PLA-DIRT&key=Cycra-…
Anyone have an issue with the front brake cable routing? Mine got jacked up last year when I did a race and I had a transponder placed behind the number plate on the left fork and I think the transponder was running into the cable and the plastic protector and clamp. Since then for the life of me, I can’t seem to get the cable to stop sliding out of the brake hose that protects the cable. I can send pictures but figured I’d see if anyone has had this issue and has been able to resolve it the way it came stock.
UPDATE: I think I figured it out. I had the brake hose at the bottom forced onto the reservoir that I think was causing the cable to pull the hose protector which was exposing the cable at the top where the protector is synching and connecting the upper and lower portion of the cable.
Thought I'd share an update on my progress with the bike. As mentioned previously this has been a difficult bike to setup and I can understand why some give up on it.
The main issue I found was it riding too low in the rear. I'm 183cm (6ft) & ~100kg with gear on and ended up on a 6.6KG Race Tech Shock Spring. The K-Tech (UK) Springs were either too soft or too firm.
JBI suspension in the US were extremely helpful in encouraging me to use spring pre-load to guide spring rate, and completely disregard free/static sag. I am at 6mm of pre-load and 100mm rider sag at the moment.
Adding the FCP race cups does gain some stability, particularly under braking, but it feels to make this makes the rider sag more important as it loses some of its sharp turning ability.
Specs:
2024 YZF450
FCP cups
2025 Yamaha stock front engine mounts
REP link (provides much more hold-up under acceleration)
Akrapovic (unnecessary, just looks cool)
X-Trig clamps (feels less comfortable than the stock clamps but allows me to use a +5mm riser)
Raptor -5mm down -5mm back pegs (combined with the +5mm riser gives me a comfortable riding position)
Replaced stock sprockets 13-49 with 14-52 to free-up shock movement
Your text says 2024 stock linkage knuckle but the pic has REP knuckle. Are you saying that REP knuckle is the exact same dimensions as stock 2024?
Rep is different than the 24 and 25 linkage. It’s like a hybrid. Stiffer than the 24 at top of range and similar stiffness to 24 at end of stroke.
There is a stiffness curve of the REP link in this thread that shows the curve vs the 23/24 vs 25 linkage but I can’t find it.
https://www.keeferinctesting.com/rep-linkage-2023-2025-yamaha-yz450f/
Well spotted, that was a mistake. Edited my post.
I did try the 2025 stock Yamaha knuckle and didn't like it. The shock felt like it rode high around the track but then still blew through the travel under acceleration.
kwoody51 is right in that the REP link feels like the best of both worlds.
Here is chart with the linkage rate over the travel of the shock.
I ended up with somewhat similar on my 24. No plans on changing anything else except for swapping front brake out. Really happy with the way it does everything now.
Luxon triple clamps and handlebar mounts set @ 23mm offset (tried 24 but pushed the front end to much on our tight local tracks)
Luxon engine mounts
REP linkage
Ohlins fork inserts and shock revalved to match (had ENZO initially but couldnt get comfortable on it) Super happy with this setup
13/50 gearing
Full procircuit Ti 6 exhaust
Twin air power flow setup with P3 carbon air box lid (sounds badass)
Vortex mapped by XPR
Rekluse CX radius 4.0 with hydro clutch setup
raptor pegs 5mm down
Guts seat foam with winged seat cover (this was a massive help for me)
Has anyone tried the Merge linkage knuckle? It seems similar to the REP linkage in that it uses a lighter spring. I wish I had the overlay of them all.
Pit Row
The REP doesn’t use a lighter spring.
If you use the REP linkage on a ‘25 you may have to use a heavier spring. On the 23 and 24 you can use the stock spring but will have to take out a little preload, from stock linkage, to get your desired sag.
This is REP and stock
Quick question, referring to the support that the fuel tank cover clips to (circled in the below photo, I borrowed from Keefer’s page), does anyone else’s flex quite a bit? Mine has a bit of movement, not enough that the filter cage pops out, but enough to have me wonder if it’s another flaw in the airbox design or if it’s an assembly/manufacture issue. It’s been the same since new.
Sorry, I was backwards on that. The Merge linkage recommended a lighter spring, not REP. REP was stock on 23/24 and heavier on the 25 if you are in the target weight range.
Thanks, I have that. I wish I had the overlay of the Merge knuckle also.
Just wanted to share my input on this gen 450, after trying one. I'm not a 450 guy, really, but I just really like Yamaha 250Fs and 2strokes and obviously wanted to try this bike for a while now. From some experiences in this thread and in the media, I kept wondering why people still love this bike, when it seems like it has some stand-out flaws. But that's really the story, for me. I came away pretty blown away with it, even though some negative did stand out. The good is the power and delivery. Very exciting and kind of helps the chassis feel playful. The handling was incredible. Initiating a turn and how it flicks around was 350-like, if not better. I couldn't believe that. Very cool. The bad is just the power is just so much. I think I could ride the bike fine but if I get into a sketchy situation, I could see it getting away from me rather quickly. And the front dances. It almost is a sensation like the head bolt is overly loose. It's odd because my 250F is the prior gen and it's perfect, I think (as far as the balance of cornering and stability.) The 450 of that same gen (18-22) is really good too but that "stuck to the ground" front end and overly stable feel do add to that bike feeling a bit big and heavy. That feeling is gone on the current one but then you get a front end that sort of wanders, instead. So I guess it's give and take. I would probably rather have the current chassis on the 450 but old chassis on the 250F. So even though I knew the chassis was busy and the power could be overwhelming (2 things I typically don't like,) I still came away really liking this 450. Anyways, just wanted to share since I was excited to ride one. I'm sure I'll be riding it more and I think if I owned one, I could probably give a better analysis after setting it up for me. Not sure if I would actually buy one, but if I did decide try something other than a 250F, it'd probably be this 450. Great bike.
Anyone try 20mm triple clamps? I just bought a set of Kroc, and in the box was Ride split 20mm Yamaha short stem. 🤦♂️
Think most have gone the other way, 23,23.5 or 24mm.
I haven’t heard of anyone going to 20mm. Give it a shot and tell us what you think!
I don't have a great answer, but I hate this design. Mine has popped off a few times. I asked at the SMX race this weekend what all of the Yamaha guys were doing to secure it. 2 answers - 8mm bolt with locker at the bottom and others were using the DCMX button https://dcmxtools.com/products/quick-seat-release-yamaha-yz250f-yz450f
I’m a slob I can’t decide which kit I want to run
Both sweet, but im a fan of all blue.
Hearing that 2026 riders are changing out the airbox to the 23-25 version for more power/hit. Anyone put a 26 airbox in a 23-25 to calm it down?
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