Yamaha Transmission Failure

mxracer71
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1/23/2024 5:47am

Look how everyone rides now…as soon as there in the air they are full gas and don’t let off when the back tire hits the ground. After awhile that has to take a tole on the tranny

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Motofinne
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1/23/2024 5:51am Edited Date/Time 1/23/2024 5:53am

Matthes was so uncomfortable when Phil opened up about it. That is what money does to you, so much for journalistic integrity. 

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MxAddic
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1/23/2024 6:04am

Matthes has been a cuck for the MX deep state his entire career. Journalistic integrity was never a priority.

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ML512
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1/23/2024 6:46am
Slack jaw wrote:
I believe that the PC team used (or still do as said above) to make build there gear box in UK from a company that makes...

I believe that the PC team used (or still do as said above) to make build there gear box in UK from a company that makes gear box for formula 1 or some thing like that...

https://www.xtrac.com/

This is who PC uses. I believe Star uses them as well, but I could be wrong on that part.

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1

The Shop

ML512
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1/23/2024 6:48am
ML512 wrote:

One thing to note is the stock transmission isn't designed to take on a 20% gain in power over stock.

valveless wrote:

Can’t that be said about all of the manufactures?

In a sense, yes. That's also why some top 250 teams have to go the route of upgrading the transmission.

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dinger212
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1/23/2024 7:07am

I’ve been riding Yamaha two strokes since 2004. Zero problems. For what it’s worth 

philG
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1/23/2024 7:16am
mxracer71 wrote:
Look how everyone rides now…as soon as there in the air they are full gas and don’t let off when the back tire hits the ground...

Look how everyone rides now…as soon as there in the air they are full gas and don’t let off when the back tire hits the ground. After awhile that has to take a tole on the tranny

Exactly this, people riding like dumb fucks and wondering why shit breaks. 

WOT with no load to full suspension compression, with WOT is just asking for stuff to break. 

In 50 years of racing, i have broken 1 gearbox, on an 83 Suzuki. 

Pro's are going to kill stuff because they can, but there is no need to destroy stuff just because you want to sound fast. 

 

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seth505
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1/23/2024 7:34am

Sorry to break it to you peoples but landing on the gas is proper technique to not have your bike feel like it's falling out the sky and splatting. 

Only transmission I ever destroyed on a bike was a YZ Whistling

10
1/23/2024 8:00am
seth505 wrote:
Sorry to break it to you peoples but landing on the gas is proper technique to not have your bike feel like it's falling out the...

Sorry to break it to you peoples but landing on the gas is proper technique to not have your bike feel like it's falling out the sky and splatting. 

Only transmission I ever destroyed on a bike was a YZ Whistling

Same 

mxtech1
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Galesburg, IL, USA
1/23/2024 8:40am

Most of the failures seem to be traceable back to issues with the OEM gear shaft stiffness. Most teams are going to utilize an aftermarket approach with custom designed shafts, dogs, & gears with stronger (more $$$$) materials & superior manufacturing methods to increase the overall stiffness of the gearbox while also improving shifting performance & fine tuning the gear ratios to suite the engine's power delivery. 

ML512
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1/23/2024 8:41am
Motofinne wrote:

Matthes was so uncomfortable when Phil opened up about it. That is what money does to you, so much for journalistic integrity. 

Steve knew what happened to Phil's bike before he had him on the show and still had him on, knowing he'd likely talk about it. If it was an issue, Steve just wouldn't have had him on the show.

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1
1/23/2024 8:46am
Motofinne wrote:

Matthes was so uncomfortable when Phil opened up about it. That is what money does to you, so much for journalistic integrity. 

ML512 wrote:
Steve knew what happened to Phil's bike before he had him on the show and still had him on, knowing he'd likely talk about it. If...

Steve knew what happened to Phil's bike before he had him on the show and still had him on, knowing he'd likely talk about it. If it was an issue, Steve just wouldn't have had him on the show.

If there was any discomfort displayed by Steve, it was concern that his buddy Phil was going to get in trouble for speaking the truth as he sees it. Not in that he is bought off by Yamaha.

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1
1/23/2024 9:41am
dinger212 wrote:

I’ve been riding Yamaha two strokes since 2004. Zero problems. For what it’s worth 

Neither have I. It seems to be a problem with many YZ250s though. From my experience when it happens to someone, it keeps happening to them, but when it doesn’t, it never does. 

mikelawlor
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1/23/2024 9:43am

I’ve blown second gear out of a YZ 450 and have had multiple people blow YZ 250 trannys apart. The 250 two stroke is a design flaw that they just don’t care to change. It only has a 3 dog window instead of 4 like most Other bikes. The 450 blew about half the teeth off second gear. Going back to what ML said they don’t design the thing for the consumer to go wide open 4th gear through the whoops. They could but then the price would jump up $500. I will say the Planko tranny in my KTM physically looks better and stronger than the ones in the jap bikes. 

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mikelawlor
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1/23/2024 9:50am

IMG 0506 1.png?VersionId=STSMPzPTY9IMG 0900 6.jpeg?VersionId=MOPZoAEI0jQLkpun8Honda transmission on top  KTM on bottom  you can just see the difference in quality in material  sorry I thought I had a broken down pic of the Honda but I don’t  

 

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Braapn105
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il, PW, USA
1/23/2024 9:53am

Hi, Fat slow C rider here. I had a transmission fail on my 2021 YZ250f with 8 hours on it. I'll see if i can find the photos. My fix worked great. I bought a honda.

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MxAddic
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1/23/2024 10:04am Edited Date/Time 1/23/2024 10:38am
mikelawlor wrote:
I’ve blown second gear out of a YZ 450 and have had multiple people blow YZ 250 trannys apart. The 250 two stroke is a design...

I’ve blown second gear out of a YZ 450 and have had multiple people blow YZ 250 trannys apart. The 250 two stroke is a design flaw that they just don’t care to change. It only has a 3 dog window instead of 4 like most Other bikes. The 450 blew about half the teeth off second gear. Going back to what ML said they don’t design the thing for the consumer to go wide open 4th gear through the whoops. They could but then the price would jump up $500. I will say the Planko tranny in my KTM physically looks better and stronger than the ones in the jap bikes. 

Their boxes suck. Can't imaging their tranny's being any better.

tackle

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GrapeApe
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1/23/2024 11:03am
mikelawlor wrote:
I’ve blown second gear out of a YZ 450 and have had multiple people blow YZ 250 trannys apart. The 250 two stroke is a design...

I’ve blown second gear out of a YZ 450 and have had multiple people blow YZ 250 trannys apart. The 250 two stroke is a design flaw that they just don’t care to change. It only has a 3 dog window instead of 4 like most Other bikes. The 450 blew about half the teeth off second gear. Going back to what ML said they don’t design the thing for the consumer to go wide open 4th gear through the whoops. They could but then the price would jump up $500. I will say the Planko tranny in my KTM physically looks better and stronger than the ones in the jap bikes. 

MxAddic wrote:
Their boxes suck. Can't imaging their tranny's being any better.

Their boxes suck. Can't imaging their tranny's being any better.

tackle

So he doesn't know how to spell Pankl and you don't know how to spell Plano lol

 

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MxAddic
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1/23/2024 11:12am
GrapeApe wrote:

So he doesn't know how to spell Pankl and you don't know how to spell Plano lol

 

Sure...

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mx317
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1/23/2024 12:20pm
dinger212 wrote:

I’ve been riding Yamaha two strokes since 2004. Zero problems. For what it’s worth 

What gear are you hitting SX whoops in?

7
soggy
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1/23/2024 12:42pm
mikelawlor wrote:
I’ve blown second gear out of a YZ 450 and have had multiple people blow YZ 250 trannys apart. The 250 two stroke is a design...

I’ve blown second gear out of a YZ 450 and have had multiple people blow YZ 250 trannys apart. The 250 two stroke is a design flaw that they just don’t care to change. It only has a 3 dog window instead of 4 like most Other bikes. The 450 blew about half the teeth off second gear. Going back to what ML said they don’t design the thing for the consumer to go wide open 4th gear through the whoops. They could but then the price would jump up $500. I will say the Planko tranny in my KTM physically looks better and stronger than the ones in the jap bikes. 

MxAddic wrote:
Their boxes suck. Can't imaging their tranny's being any better.

Their boxes suck. Can't imaging their tranny's being any better.

tackle

GrapeApe wrote:

So he doesn't know how to spell Pankl and you don't know how to spell Plano lol

 

He’s never told a funny. 

MxAddic
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1/23/2024 12:56pm
soggy wrote:

He’s never told a funny. 

I guess you are worried after all...

"I don’t worry about you. Couldn’t care less"

3
soggy
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1/23/2024 1:08pm Edited Date/Time 1/23/2024 1:12pm
soggy wrote:

He’s never told a funny. 

MxAddic wrote:

I guess you are worried after all...

"I don’t worry about you. Couldn’t care less"

Sure…

 

care to explain your hilarious joke?

MxAddic
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1/23/2024 1:14pm
soggy wrote:

Sure…

 

care to explain your hilarious joke?

Only if your worried?

2
philG
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1/23/2024 1:33pm
seth505 wrote:
Sorry to break it to you peoples but landing on the gas is proper technique to not have your bike feel like it's falling out the...

Sorry to break it to you peoples but landing on the gas is proper technique to not have your bike feel like it's falling out the sky and splatting. 

Only transmission I ever destroyed on a bike was a YZ Whistling

There is a world of difference between landing on the gas, and landing WOT . 

A skilled rider lands with matched speed, you do not see the spike loads in the gearbox doing that. 

When you land with the wheel doing 60mph and the engine under no traction, as soon as it grips , the whole tranny slows up, and the motor doesnt and shit lets go. 

When i worked in WRC, we used to stress test cranks by doing 100 WOT landings , because it would snap the end off the crank like a carrot with the spike loading , because the gearboxes were so strong to take the 4WD loading on asphalt with slicks. 

And i have been in the car when they do it and its brutal, because you cant cant shut off because the car will nose dive, so you have to keep it pinned . 

Its simple physics , you can stop the gears breaking, but then something else will go. 

I saw a YZ250 motor today that was destroyed, due to a catastrophic failure , that was just down to abuse, no parts were worn, just busted..  and its always the same people who blow stuff up. 

There are people you can watch riding , and know you are never ever going to buy a bike off them, and while i know i have never been Pro level, there are just as many 'slow' destroyers as there are fast ones. 

 

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jbrown15
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1/23/2024 1:38pm
NorCal1975 wrote:
My 16 year old has over 300 hours on his 2021 YZ250f, zero tranny work, shifts perfectly.  I just rode it a few days ago.  He...

My 16 year old has over 300 hours on his 2021 YZ250f, zero tranny work, shifts perfectly.  I just rode it a few days ago.  He is pretty fast and rides it  hard, but he DOES use the clutch when he shifts (or so he tells me, lol).  Bike has been absolutely bullet proof so far, now I jinxed it I know.  Motor is stock, but does have a full FMF exhaust.      

No disrespect but it feels like this post is just trolling....lol

Sorry but your 16 year old isn't putting the same stress on the transmission that a top pro racing supercross is.

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Village Idiot
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1/23/2024 1:54pm
seth505 wrote:
Sorry to break it to you peoples but landing on the gas is proper technique to not have your bike feel like it's falling out the...

Sorry to break it to you peoples but landing on the gas is proper technique to not have your bike feel like it's falling out the sky and splatting. 

Only transmission I ever destroyed on a bike was a YZ Whistling

philG wrote:
There is a world of difference between landing on the gas, and landing WOT .  A skilled rider lands with matched speed, you do not see...

There is a world of difference between landing on the gas, and landing WOT . 

A skilled rider lands with matched speed, you do not see the spike loads in the gearbox doing that. 

When you land with the wheel doing 60mph and the engine under no traction, as soon as it grips , the whole tranny slows up, and the motor doesnt and shit lets go. 

When i worked in WRC, we used to stress test cranks by doing 100 WOT landings , because it would snap the end off the crank like a carrot with the spike loading , because the gearboxes were so strong to take the 4WD loading on asphalt with slicks. 

And i have been in the car when they do it and its brutal, because you cant cant shut off because the car will nose dive, so you have to keep it pinned . 

Its simple physics , you can stop the gears breaking, but then something else will go. 

I saw a YZ250 motor today that was destroyed, due to a catastrophic failure , that was just down to abuse, no parts were worn, just busted..  and its always the same people who blow stuff up. 

There are people you can watch riding , and know you are never ever going to buy a bike off them, and while i know i have never been Pro level, there are just as many 'slow' destroyers as there are fast ones. 

 

Impulse force loading - that's an effective way to find the weakest link. Sounds like the job might have had some fun moments. Cool

And no, you're right, you don't have to be a pro to be good at breaking stuff - virtually anyone can be proficient at it if they're ignorant of proper operation and the potential consequences of failing to do so - hence your comment about a skilled rider.

VonShofstall
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1/23/2024 3:11pm
Slack jaw wrote:
I believe that the PC team used (or still do as said above) to make build there gear box in UK from a company that makes...

I believe that the PC team used (or still do as said above) to make build there gear box in UK from a company that makes gear box for formula 1 or some thing like that...

ML512 wrote:

https://www.xtrac.com/

This is who PC uses. I believe Star uses them as well, but I could be wrong on that part.

@ML512 That's the name I was trying to remember. When NYK came from PC to MDK motors in 07 he was asking for some custom XTRAC internals. I recall it was pricey stuff. That said, it would be like buying the life insurance package to know that your tranny is much less likely to lock up in a rhythm section. 

byke
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1/23/2024 3:19pm
truck wrote:
I find it hard to believe that they are designing and manufacturing something that wouldn't be expected to handle a 20% increase in power. I know...

I find it hard to believe that they are designing and manufacturing something that wouldn't be expected to handle a 20% increase in power. I know gear ratios change, but is the basic design and components all the different in the 250 than the 450? If the problem is in the 250 only it would seem that it's a specific design flaw. 

+1. There's no way that there are any critical parts on the bike that can't handle 1.2x normal working load, especially when the lifespan of race bikes is so short.

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Cycle Sport
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New Bern, NC, USA
1/23/2024 3:22pm

I’ve been on YZ250 2 strokes since 2008, probably 7 or so bikes.  I sell them after I put about 100 to 150 hours on them (2 or 3 years).  I had tranny failures on every one.  Usually get 75 hours or so between failures and usually it is the dogs on third gear get rounded and it pops out of gear, a couple times it was a broken gear tooth.  I’m an older vet rider, 63 now, but love to ride.  BelRay Gearsaver oil helped.  I fix them myself.

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