clacking noise in middle gear area

[Vmx2001]

Has anyone else run into this problem?
I was riding home, pinned it while moving 50mph & it felt like the rear wheel stopped moving for a second then it did it again.
I backed off & it seemed to run fine.
I took it out the next day to recreate the issue & it did it again only in a different gear at slower speeds.
I stopped the bike, put it on the side stand so I could get closer to the area of the noise.
Revved the engine heard the clacking & got closer to it... revved the engine & the bike lept forward & fell over.
I pulled the swing arm off & the driveshaft looks good... the u joint looks good.
I was going to unbolt the cover to the middle gear but didn't know if I could just pull it out or if this is when the split needs to be done.
any help is appreciated.
Thanks

 

[Radioguylogs]

While in neutral, something made the bike move.

Ideas:

A loose part floating around bounced into the transmission gears?

Something in the transmisssion linkage, drum or forks is floating?

 

[Vmx2001]

While in neutral, something made the bike move.

Ideas:

A loose part floating around bounced into the transmission gears?

Something in the transmisssion linkage, drum or forks is floating?

i'm wondering if a tooth could have broken off the middle gear & done that?
But what woulld cause the feeling of the tire stopping?

 

[maleko89]

You'll need to split the cases to diagnose and repair the transmission. You might be able to scope out something broken in the middle gear by removing output middle gear but not the whole transmission.

 

[Radioguylogs]

i'm wondering if a tooth could have broken off the middle gear & done that?
But what woulld cause the feeling of the tire stopping?

If there was a loose part, it could jam between the teeth of the gears, and lock it up.

 

[Vmx2001]

I hope I'm wrong because if it is something other than the output shaft ... no more max... the cost to repair the trans is prohibitive & I could buy another one for about the same price, as I have no room to pull the motor & split

If new bike I'll be parting out the old one.

I couldn't see anywhere to explain if the output shaft (from the middle gear) could just be pulled out & put back in, without special tools. basically no procedure could be found.
I'm putting the swing arm back on & removing the middle gear cover to see if anything shows itself.
the u-joint moves freely as does the output shaft.

 

[Radioguylogs]

Might try rotating the rear wheel on the centerstand (in neutral) to see if you learn anything.

Next I would remove the oil pan to see if anything is in there.

Then, while the oil pan is off, rotate the transmission parts see what you feel and hear? You can remove the spark plugs to make it easier to rotate the drivetrain.

 

[Stephan]

You definitely have to split the cases to remove the output shaft which is why there is no specific procedure, it's just part of the transmission overhaul after you split the cases. If your problem occurs at a higher speed it could be quite hazardous so best fix it good and proper.

 

[Vmx2001]

I recorded the sound & took pics... tell me if you've heard or seen this before.. it does not bode well as far as I can tell

 

[Vmx2001]

Can I remove the bearing for a better look inside?

 

[Vmx2001]

Might try rotating the rear wheel on the centerstand (in neutral) to see if you learn anything.

Next I would remove the oil pan to see if anything is in there.

Then, while the oil pan is off, rotate the transmission parts see what you feel and hear? You can remove the spark plugs to make it easier to rotate the drivetrain.

that was my next move after removing side cover, not sure if it's necessary now ... see my new addition below.

I do appreciate all the help you guys are giving me...if I'm right about my suspicions,
(never jump the gun though) there is a new parts bike available...lol

 

[maleko89]

The sounds I hear are not normal. To remove that bearing, need to remove that big nut but also a press or special press tool to press the bearing race down and pull out the middle gear spring retainers out. I doubt it can be done on the bike and the counter shaft will need to be completely removed in order to disassemble.

To inspect middle gears, I went at it from the other way by removing the rear wheel, final drive, swingarm. then, loosen two engine case bolts and remove three screws to remove the u-joint and middle driven gear. Check both middle gears and the damper cam. You probably won't be able to inspect the other side of the counter trans shaft or main trans shaft and will need to remove engine, split the cases, and entire transmission inspected and fixed. You're looking at around $600 to get the transmission gears/shafts fixed assuming it's there. I'm not sure if Sean can repair the middle gears or not? You can't get those parts from Yamaha anymore.

 

[Vmx2001]

Yeah it didn't sound healthy.
I'm just wondering what could have caused the bolt/screw heads to break off... only on the top?

I had the swing arm & drive shaft off but wasn't sure how to remove the middle gear drive shaft.
So I have to loosen the engine case bolts... good to know.
I'll take a look at it & dedtermine my next move.
I don't have the space to remove & split the engine, unfortunately.
It's too bad I bought the bike brand new & have 90k on it.. the motor still runs strong...I love this bike.
Perhaps it's time for a Gen 2

I really appreciate the help everyone has given, you guys are great!