This ought to be interesting. To me this looks like material failure and Yamaha's answer sounds really sketchy. I think I saw another T9Gt transmission failure thread somewhere last year.  https://www.facebook.com/groups/405696997251560/posts/1018925415928712/

Edited August 21, 20231 yr by Turd Ferguson

It's a private group. Cannot see the post unless you join the group???

Yea I don't have a FB account so unable to read any posts...

Post:

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So they're saying the manufacturing and assembly processes are fine, and bad components aren't considered?  Ugh.

YEah, this is VERY different from any vehicle warranty in the past where material defects are ALWAYS covered. I find this hugely concerning. If manufacturers go this route warranties will become entirely useless.

Thats sucks. I wonder how much the repair bill will be and what was the mileage?

Hate to break it to everyone but the reality is that type of failure is NOT a result of poor manufacturing but almost always caused by poor shifting and riding techniques by the operator. 

The bike isn’t new, the post says it’s 2 weeks outside of factory warranty (meaning 2 years old) and as such doesn’t fall under a “reasonable wear and tear” type of scenario. 

Where are photos of the rest of the tranny components? IIRC the gear dogs were excessively worn which indicates improper shifting technique. I also don’t recall seeing how the shift forks looked…

If it was a factory defect, those gears would have failed within the first 1k miles/kms  

it would have been nice if Yamaha would split the cost of repairs (cover parts maybe but customer pays labor) but it’s a different world then it was 15 years ago.  They have no control over HOW their product is treated so they have to draw a line somewhere.

sucks for everyone involved.

-Skip

9 minutes ago, skipperT said:

Hate to break it to everyone but the reality is that type of failure is NOT a result of poor manufacturing but almost always caused by poor shifting and riding techniques by the operator. 

-Skip

Help me to understand what 'poor shifting and riding technique' could cause a failure like this?

23 hours ago, Heli ATP said:

Help me to understand what 'poor shifting and riding technique' could cause a failure like this?

From a technical standpoint it’s a big answer that would be easier in person and with components in front of me. 

To put it simply, shifting at the wrong times (not following the arrows that indicate when a shift is possible), forcing gear changes when the conditions aren’t correct so that the gears don’t smoothly engage or disengage as designed, or not being firm enough with an up shift or downshift such that components in the trans aren't fully engaged or disengaged and are then loaded or unloaded in a partially shifted position, etc…. These are just the ones I can think of off the top of my head.

any of these situations puts spinning gears, dogs, shafts, shift drums, forks etc into a position where they can potentially interfere with each other and wear in a way prematurely.

If this situation happens in just the right way even once if unlucky, more than once if the operator is lucky, and damage occurs and particulate bounces around the transmission components - then gears can get broken off and chunks can fracture and you will find the damage once the cases are split. 

-Skip

 

Very reasonable points.  Thanks skip

3 hours ago, skipperT said:

From a technical standpoint it’s a big answer that would be easier in person and with components in front of me. 

To put it simply, shifting at the wrong times (not following the arrows that indicate when a shift is possible), forcing gear changes when the conditions aren’t correct so that the gears don’t smoothly engage or disengage as designed, or not being firm enough with an up shift or downshift such that components in the trans aren't fully engaged or disengaged and are then loaded or unloaded in a partially shifted position, etc….

 

Found this youtube video on the subject. I guess incorrectly using a quickshifter could cause damage too?

You may be destroying your XMSN

I don't think we are getting the full story here. There are multiple points of damage here and with out full pictures of the tear down no conclusion can be made. All the parts of the transmission need to be shown.

It was posted that while it was just out of warranty, Yamaha was going to cover it, but then after i guess the investigation decided it was not manufacture defect.

Here is what I found from this one picture showing more then just a missing tooth and chipped tooth.

Edited August 24, 20231 yr by Eventhorizon

4 hours ago, Heli ATP said:

Found this youtube video on the subject. I guess incorrectly using a quickshifter could cause damage too?

You may be destroying your XMSN

Not a bad video. And his point about if the customer only wants to repair 3rd gear, then he wouldn’t perform any of the work - is exactly what I would say as well. You can’t do that type of repair job half-assed. 

But to answer your question, @Heli ATP IMHO yes - That type of damage could also be caused by the operator’s foot with or without a quickshifter. 

As was pointed out in the video, or maybe it was a bit vaguely mentioned - but it only takes that one thing to begin to wear/or a bent or broken bit to cause a chain of events that will destroy gearcase and shifting components if it’s not attended to. 

I haven’t split CP3 cases, so I can’t speak from direct experience on our bikes - but I’m sure Yamaha made some internal changes in the some of the transmission and shifting components from FJ Gen to /MT 9GT and + Gen to allow the quickshifter to both function smoothly and have longevity. I have had KTMs apart and they certainly have some different elements when compared to previous Metric engine designs without QSers from the factory. But some of the designs haven’t changed much over the years either….

-Skip

3 hours ago, Eventhorizon said:

I don't think we are getting the full story here. There are multiple points of damage here and with out full pictures of the tear down no conclusion can be made. All the parts of the transmission need to be shown.

It was posted that while it was just out of warranty, Yamaha was going to cover it, but then after i guess the investigation decided it was not manufacture defect.

Here is what I found from this one picture showing more thanjust a missing tooth and chipped tooth.

The 2 LH arrows on your diagram may actually be pointing to a deliberately designed angle on the shift dog to help engagement - it’s hard to know based on this pic and without a comparison of the design of the other dogs and slider gears. But if yamaha produced it to be similar to traditional gear productions, then yes those areas are worn.

I would 100% agree with your 2 RH arrows however, @Eventhorizon got some missing chunks there….

-S