2023-2025 yamaha yz 450f reliability problems

Edited Date/Time 12/14/2024 6:39am

Hello everyone, just curious if anyone also’ve had such problems with new yamahas

Quick story: 2 years ago i had to switch from 250 class to 450 and was choosing a brand to go with. i’ve always was a ktm rider just because of the engine reliability and overall power output but there always were hudge problems with setting up the suspension (even very expensive aftermarket kits). so i decided to pick a new 2024 yamaha yz 450 since i liked how it feels on the track and i’ve heard of its great build quality

And the problems started early. Clutch burnt on 9 hours (i’ve never burnt a clutch on my ktms, even on my 450 practice bike). On ktm i replaced my clutch once a year in offseason and this malfunction on yamaha was a surprise for me. And then, after another 10 hours clutch’ve burnt AGAIN. i searched on the internet about clutch problems, found that this problem is quite common on new yamahas and the best solution is to buy an aftermarket clutch basket (or replace 8 yamaha’s clutch plates with 9 ktm’ ones). since that i’ve spent another 20 hours (until i tore my acl) and it’s been working great but i don’t know for how long it will keep working

That was not the only problem. Now, it is offseason, so it is time to prepare the bike for upcoming season. And, as i found out, you need to replace your rod every 50 hours to prevent its malfunction (ofc if you ride fast enough). There are a lot of stories on the internet how rod just snapped in half on new yzs. As for a rider who comes from racing ktms whole life, it is ridiculous. My close friend, european champ, currently rides on a ktm 450 and replaces his rod once in 200 hours.

I haven’t taken apart the engine yet to check if everything is good but i am already a bit dissapointed with the maintenance cost of a yamaha. and i’ve also heard that yamaha’s valves aren’t also the best

And, as for now, i’m already thinking about switching back to ktm just because it is cheaper to maintain, but the cost of ktms is just mindblowing. not mentioning the fact that it is nearly impossible to compete at the high level on ktm without aftermarket suspension. So maybe it is will be more profitable to maintain yamaha more frequently, since i feel like it is best 450 in terms of handling and engine character, idk

I’m just afraid of another unknown problems with yamaha and i will be very thankful if you tell me about them🙏🏻

2
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12/14/2024 7:40am

If your only concern with the ktm is the suspension, get the dialedmfg kyb conversion kit and a set of sss forks and you can do the conversion yourself for +-$1000

MxAddic
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12/14/2024 7:49am

I do here about quite a few gearbox problems on the internet.They have the hardest hitting engine but it's coming with a price.

1
12/14/2024 8:08am
If your only concern with the ktm is the suspension, get the dialedmfg kyb conversion kit and a set of sss forks and you can do...

If your only concern with the ktm is the suspension, get the dialedmfg kyb conversion kit and a set of sss forks and you can do the conversion yourself for +-$1000

i used to ride with full ohlins kit on my ktm race bike and kyb conversion kit + custon oil tank on the shock on my practice bike and yes, it works great but my biggest complain with new ktms is shock. good aftermarket shock costs around 2500 so it becomes quite expensive

12/14/2024 5:19pm
If your only concern with the ktm is the suspension, get the dialedmfg kyb conversion kit and a set of sss forks and you can do...

If your only concern with the ktm is the suspension, get the dialedmfg kyb conversion kit and a set of sss forks and you can do the conversion yourself for +-$1000

i used to ride with full ohlins kit on my ktm race bike and kyb conversion kit + custon oil tank on the shock on my...

i used to ride with full ohlins kit on my ktm race bike and kyb conversion kit + custon oil tank on the shock on my practice bike and yes, it works great but my biggest complain with new ktms is shock. good aftermarket shock costs around 2500 so it becomes quite expensive

Ahh I see. Rough on acceleration chop?

The Shop

12/15/2024 12:53am
If your only concern with the ktm is the suspension, get the dialedmfg kyb conversion kit and a set of sss forks and you can do...

If your only concern with the ktm is the suspension, get the dialedmfg kyb conversion kit and a set of sss forks and you can do the conversion yourself for +-$1000

i used to ride with full ohlins kit on my ktm race bike and kyb conversion kit + custon oil tank on the shock on my...

i used to ride with full ohlins kit on my ktm race bike and kyb conversion kit + custon oil tank on the shock on my practice bike and yes, it works great but my biggest complain with new ktms is shock. good aftermarket shock costs around 2500 so it becomes quite expensive

Ahh I see. Rough on acceleration chop?

yep, also i feel like rebound is unpredictable, no matter how you try to tame it with clicks it will still do crazy things on big bumps on straightaways, on breaking bumps, on big sand bumps. and i feel like the rebound is not the major problem. there is no hold up in the lower stroke of the shock, it deeps out to much and that results as a hudge unpredictable kick. i think wp shocks went progressively worse over the time. i know that in every test people tend to say that “ktm upgraded their suspension and this is the best suspension on a ktm ever” but as of my riding experience 16-18 wp suspension felt better (at least ridable). and ktm overall is a great bike, it is such a bummer that they can’t put anything besides wp

1
12/15/2024 1:06am
i used to ride with full ohlins kit on my ktm race bike and kyb conversion kit + custon oil tank on the shock on my...

i used to ride with full ohlins kit on my ktm race bike and kyb conversion kit + custon oil tank on the shock on my practice bike and yes, it works great but my biggest complain with new ktms is shock. good aftermarket shock costs around 2500 so it becomes quite expensive

Ahh I see. Rough on acceleration chop?

yep, also i feel like rebound is unpredictable, no matter how you try to tame it with clicks it will still do crazy things on big...

yep, also i feel like rebound is unpredictable, no matter how you try to tame it with clicks it will still do crazy things on big bumps on straightaways, on breaking bumps, on big sand bumps. and i feel like the rebound is not the major problem. there is no hold up in the lower stroke of the shock, it deeps out to much and that results as a hudge unpredictable kick. i think wp shocks went progressively worse over the time. i know that in every test people tend to say that “ktm upgraded their suspension and this is the best suspension on a ktm ever” but as of my riding experience 16-18 wp suspension felt better (at least ridable). and ktm overall is a great bike, it is such a bummer that they can’t put anything besides wp

Im running the rep linkage which does make the stroke more progressive than stock, and every other aftermarket linkage is doing the same thing as far as I know. I’m currently running a pretty soft rebound stack that was recommended by a reputable tuner and so far I like it a lot. I was worried the bike would feel more springy and step out on flat acceleration, but it doesn’t do anything weird and feels even more planted so far. Ive only had a few rides on it though. For comparison I’ve had a couple other shocks setup for me by tuners and never had this feeling in the rear

1
12/15/2024 1:19am
Im running the rep linkage which does make the stroke more progressive than stock, and every other aftermarket linkage is doing the same thing as far...

Im running the rep linkage which does make the stroke more progressive than stock, and every other aftermarket linkage is doing the same thing as far as I know. I’m currently running a pretty soft rebound stack that was recommended by a reputable tuner and so far I like it a lot. I was worried the bike would feel more springy and step out on flat acceleration, but it doesn’t do anything weird and feels even more planted so far. Ive only had a few rides on it though. For comparison I’ve had a couple other shocks setup for me by tuners and never had this feeling in the rear

maybe in europe bikes are assembled on different factory idk, but i’ve heard a lot of problems with new ktms, like a lot of typical mistakes assembling the bike, one is with shock, when it doesn’t react to clicks and feels super soft, couple of people in my region know how to fix it, but there is no warranty that after their fix the shock will peform like ktm’ve set it. and, this is not related to the suspension topic, just a fun fact, 8 out of 10 new austrian bikes that my friends bought in last 2 years came out of the box with heavily unbalanced shaft. now in our country we are used to open the engine on austrian bikes before we even ride it hahaha. it seems to be a very common problem in europe for 2 years and has not been fixed yet

1
12/15/2024 1:45am

Damn that’s pretty scary. So far so good over here, but I don’t know many people with new gen’s other than the 2 strokes 

1
6/7/2025 1:23pm Edited Date/Time 6/7/2025 1:24pm

Just want to give a little update on my 2024 yz450f.

Yes, rod issue is real. Today during the race my rod snapped, blew out the crankcase and cylinder. My bike has 50 hours, changed oil every 5 hours. i was aware of this problem but just couldn’t find any aftermarket rods in europe, but my bike exploded even earlier than i expected. overall yamaha’s parts quality is a hudge dissapointment.

I consider myself a semi-pro rider so for most of the people this is not a hudge deal because they don’t rev the bike as high as i do, but 50 hours, man, this is even early for piston replacment.

for anyone wondering, the engine rebuild cost is around 4k bucks. so if you want new yz450f, and you know that you will rev that thing high, spend your money on an aftermarket rod

IMG 4860 1.jpeg?VersionId=

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romain524
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6/7/2025 11:19pm

Bummer man! On Japanese bikes it’s safer to put a good rod when you’re a fast guy.

We had a rod go through the cases in 2018 on a RMZ 450 on SX. Fortunately it happened on a small double right before the Supercross triple…

1
6/8/2025 5:00am Edited Date/Time 6/8/2025 5:00am

UPDATE

Actually, as can be seen at the photo, rod isn’t snapped. So maybe yamaha isn’t that bad as i’ve said yesterday. There is no piston pin at the rod, so i believe it was a mistake during assembly (idk what could cause piston pin to go out, just have no other ideas) will find out the reason when i open the engine

P. S. the damage is crazyIMG 4898 0

2
Moto520
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6/9/2025 7:54am

Dude....that looks horrible.  My Yamaha has been as good as any other bike i've owned in terms of reliability.

1
6/10/2025 8:09am

Wow, that’s quite a failure. I’m really intrigued to see what everything looks like pulled apart. 

7/8/2025 3:10pm

well, here’s an update

what happened to my engine is that the piston torn off. i’ve contacted to kefeer and he said that this is caused by the notorious yz’s “con rod issue”. rod becomes loose, the load on the piston increases and it torns. there may be other reasons to cause that but we will never know.

IMG 5171 2.jpeg?VersionId=J rhZuXyPnLnO7i44RNbAGz
7/8/2025 3:18pm
well, here’s an updatewhat happened to my engine is that the piston torn off. i’ve contacted to kefeer and he said that this is caused by...

well, here’s an update

what happened to my engine is that the piston torn off. i’ve contacted to kefeer and he said that this is caused by the notorious yz’s “con rod issue”. rod becomes loose, the load on the piston increases and it torns. there may be other reasons to cause that but we will never know.

IMG 5171 2.jpeg?VersionId=J rhZuXyPnLnO7i44RNbAGz

at this point i’m confused. i love yamaha for the riding experience but i don’t trust this engine anymore. even with an aftermarket rod i can’t be sure that everything will be ok, because i’m not even sure that this was the reason (the piston was torn on 47 hours!!)

FGR01
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7/8/2025 7:43pm Edited Date/Time 7/8/2025 7:47pm

Is stock piston cast aluminum?   Put a good aftermarket rod and good aftermarket forged aluminum piston in.  

wrc777
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7/9/2025 4:43pm
FGR01 wrote:

Is stock piston cast aluminum?   Put a good aftermarket rod and good aftermarket forged aluminum piston in.  

Those thin 4t pistons are always forged. A thin, flat  cast piston won’t survive long. That is not to say all forged pistons are created equal. 

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FGR01
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7/9/2025 7:16pm
FGR01 wrote:

Is stock piston cast aluminum?   Put a good aftermarket rod and good aftermarket forged aluminum piston in.  

wrc777 wrote:

Those thin 4t pistons are always forged. A thin, flat  cast piston won’t survive long. That is not to say all forged pistons are created equal. 

Pretty sure most Japanese 4 stroke stock pistons are actually cast.  They are likely hypereutectic to make them harder and stronger, but still cast.  The OEM YZ450F piston is only $85.  There's no way that's a forged piston.  Also, likely part of the reason they spec such a low change interval.  In this thread, look at the pics of a late model YZ450F piston.  On the crown you can see the mark where the stem from the pour into the mold was removed and you can see molded, raised markings on the bottom, typical of casting.  

https://www.vitalmx.com/forums/moto-related/2023-24-yamaha-yz450-engine…

wrc777
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7/10/2025 8:29am Edited Date/Time 7/10/2025 8:30am
FGR01 wrote:

Is stock piston cast aluminum?   Put a good aftermarket rod and good aftermarket forged aluminum piston in.  

wrc777 wrote:

Those thin 4t pistons are always forged. A thin, flat  cast piston won’t survive long. That is not to say all forged pistons are created equal. 

FGR01 wrote:
Pretty sure most Japanese 4 stroke stock pistons are actually cast.  They are likely hypereutectic to make them harder and stronger, but still cast.  The OEM...

Pretty sure most Japanese 4 stroke stock pistons are actually cast.  They are likely hypereutectic to make them harder and stronger, but still cast.  The OEM YZ450F piston is only $85.  There's no way that's a forged piston.  Also, likely part of the reason they spec such a low change interval.  In this thread, look at the pics of a late model YZ450F piston.  On the crown you can see the mark where the stem from the pour into the mold was removed and you can see molded, raised markings on the bottom, typical of casting.  

https://www.vitalmx.com/forums/moto-related/2023-24-yamaha-yz450-engine…

A vertex forged piston kit is about the same cost as the Yamaha so the oem could be forged. That picture you linked to looks forged to me. Forged triple clamps look rougher than that. 

7/11/2025 8:04pm
FGR01 wrote:
Pretty sure most Japanese 4 stroke stock pistons are actually cast.  They are likely hypereutectic to make them harder and stronger, but still cast.  The OEM...

Pretty sure most Japanese 4 stroke stock pistons are actually cast.  They are likely hypereutectic to make them harder and stronger, but still cast.  The OEM YZ450F piston is only $85.  There's no way that's a forged piston.  Also, likely part of the reason they spec such a low change interval.  In this thread, look at the pics of a late model YZ450F piston.  On the crown you can see the mark where the stem from the pour into the mold was removed and you can see molded, raised markings on the bottom, typical of casting.  

https://www.vitalmx.com/forums/moto-related/2023-24-yamaha-yz450-engine…

Yamaha 4 stroke pistons are forged

Austin_Rankin
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7/24/2025 3:59am

I have said it time and time again….



If your riding a Japanese bike, and your not running a Carillo rod with CP piston, you best get to the point ASAP to where you are running those parts or this happens. Hate to see it.

1

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