Broken my gears :-(

[AdamFZ]

Little video of the gears....

2005 Yamaha FZ6-S Transmission Exposed - YouTube

 

[TownsendsFJR1300]

TownsendsFJR1300, Thank you but that's just the flash making it look like that. I've double checked and no cracks or chips.

I'm having a mare of time getting the torx screws out holding the input shaft and bearings in.... They are punched to secure them but i can't lift the little flap so i tried drilling it off but again no luck. I'm starting to round them off if i try anymore and that will leave me 1 option... drill them out ! Anyone have suggestions ?

Ok, guess it was the flash.

As for the torx screws, if their not to torn up yet, did you try a hand held impact driver with a torx bit? The tool looks like this:

LISLE CORPORATION Hand Impact Tool Set - Tools - Air Compressors & Air Tools - Impact Wrenches

If you don't have one you get one pretty cheap (under $20.00 US). When smacking the tool to loosen the screw/bolt, it also pushes the bit downward into the bolt/screw which helps keep from stripping it. Make sure the case is WELL SUPPORTED UNDER IT. That tool works very well as long as it has something to grab.

If that doesn't work, I suspect those retainer torx screws are NOT SS and as you mentioned, drill the head till the plate comes off. Hopefully there's enough stud left you can just grab it with a vise grip and remove.

I just checked the YAMAHA, 05 shop manual, their only torqued to less than 9 ft lbs but DO HAVE LOCKTITE on them. Some heat would trying to remove would definitly help break the LT.


Off topic a sec, whats that really long chain flopping around the case go to?? It looks like the cam chain, but super long???

 

[AdamFZ]

Thanks.

That small chain drives the oil and water pumps

 

[FinalImpact]

Heat coupled with impact and you should be good. A hand held propane torch for about a minute. Allow about 2 - 3 minutes for heat to transfer and hit it.

USE a FLAT round punt to KNOCK DOWN the edges pushing them back into formation before they torx bit rounds out. Use your grinder to freshen the tip of the torx bit but dont let it get hot or the heat treating will soften.

If no impact tool as Scott suggested, go for the the blunt nose punch and 16oz hammer AFTER heating to break the locktite free. Don't underestimate the flat punch for pushing the torn up socket cap back down and making the bit fit tight again.

 

[iSteve]

I know this sound kind of mean spirited but my buddy and I have been following this thread for 4 days now. We have a $10 bet on what it is. I said the noise has nothing to do with the transmission because the clutch would slip long before a tooth would shear off a gear. He said he wouldn't bet that it was a gear but definitely something in the transmission.

I kind of hope it is something in the transmission now because of all the work you have done. After looking at the pictures I can't help to think that the broken exhaust mount.

Good Luck

 

[TownsendsFJR1300]

I know this sound kind of mean spirited but my buddy and I have been following this thread for 4 days now. We have a $10 bet on what it is. I said the noise has nothing to do with the transmission because the clutch would slip long before a tooth would shear off a gear. He said he wouldn't bet that it was a gear but definitely something in the transmission.

I kind of hope it is something in the transmission now because of all the work you have done. After looking at the pictures I can't help to think that the broken exhaust mount.

Good Luck

From Post #12:
Noise is only in 2nd gear.... Rest of the gears are normal. Its not a constant grinding noise, it comes and goes and gets faster as i go faster. It's like a couple of teeth have sheered off on 2nd.

I know as fact you can indeed, shear off teeth without the clutch as I did it on a YZ 125 two stroke years ago(coming off a jump). Second gear and second idler gear. One gear WAS a press on fit...

If I was in Adam's shoes, I'd gone the same route and done the same, tearing down vs leaving it and potentially/likely causing more damage..

In either case, he'll find the problem... No doubt in my mind...

 

[FinalImpact]

From Post #12:
Noise is only in 2nd gear.... Rest of the gears are normal. Its not a constant grinding noise, it comes and goes and gets faster as i go faster. It's like a couple of teeth have sheered off on 2nd.

I know as fact you can indeed, shear off teeth without the clutch as I did it on a YZ 125 two stroke years ago(coming off a jump). Second gear and second idler gear. One gear WAS a press on fit...

If I was in Adam's shoes, I'd gone the same route and done the same, tearing down vs leaving it and potentially/likely causing more damage..

In either case, he'll find the problem... No doubt in my mind...

All gears are in contact all the time. If one was actually broke - bad stuff would have happened. Its why I think its about alignment more so than gear or shaft damage. Again, I suspect light contact from an adjacent gear. Because IT WAS NOT SUPPOSED TO HIT Neutral while in 3rd or 4th gear, it suggests the shift drum, shift rails, lockouts or lock-out detents allowed this to happen. So I vote one of the above is suspect for allowing partial gear engagement making the noise.

PS - this Trans has bigger gears and shafts than some CARS! Its the Tank of transmissions! it looks Bullet Proof!

 

[FinalImpact]

Little video of the gears....

2005 Yamaha FZ6-S Transmission Exposed - YouTube

If you can get it back to this stage and oil only the shafts and inner section of the gears bushings, any noise from friction of contact on the thrust surfaces will be 10X louder w/out the oil as a cushion.

Also - a quick flash card held up indicating the selected gear i.e. 1st gear, 2nd gear, 3rd gear would be great! I'm not the kind to talk either! lol

So recap - noise was only in 2nd gear under load or No load or both?

 

[AdamFZ]

If you can get it back to this stage and oil only the shafts and inner section of the gears bushings, any noise from friction of contact on the thrust surfaces will be 10X louder w/out the oil as a cushion.

Also - a quick flash card held up indicating the selected gear i.e. 1st gear, 2nd gear, 3rd gear would be great! I'm not the kind to talk either! lol

So recap - noise was only in 2nd gear under load or No load or both?

As soon as i can get the input shaft out and stripped for inspection i will rebuild the gears and pop it all back together. I'm gonna try and turn the gears with an electric drill to get it up to a decent speed and see if i can hear anything.

Yes, grinding noise is only in 2nd gear under load and lift off load.

 

[TownsendsFJR1300]

All gears are in contact all the time. If one was actually broke - bad stuff would have happened. Its why I think its about alignment more so than gear or shaft damage. Again, I suspect light contact from an adjacent gear. Because IT WAS NOT SUPPOSED TO HIT Neutral while in 3rd or 4th gear, it suggests the shift drum, shift rails, lockouts or lock-out detents allowed this to happen. So I vote one of the above is suspect for allowing partial gear engagement making the noise.

PS - this Trans has bigger gears and shafts than some CARS! Its the Tank of transmissions! it looks Bullet Proof!

Just as an FYI, in post #30, about 3/4's the way down, Adam has pictures of the outside shifter drum (accessable under the left side shift cover) which still has the roller wheel and spring still attached to it as it should (stopping the drum for each gear in place as it should) .

Obviously between the higher RPM's and dropping the engine into a higher gear caused damage to something.. Adam's very close to finding it.

I'd be nice it was more obvious, BUT at least it doesn't appear to be catastrophic at this point.

 

[RichBinAZ]

Hi Adam, looks like you had a lot of difficulty getting those corroded bolts apart. That might be the hard part in all this adventure.

Do you know how the gears work? Just in case... 2nd gear is the pair on the right, furthest from the clutch. For the output shaft, it spins freely on the shaft and is only locked to the shaft when the right hand shift fork slides the dogs on 6th gear into the windows on second.

This is one area to look for wear. Are the dogs rounded on the ends or are the window edges rounded.

Another area to look is the bearings, which should turn freely and smoothly. They probably do. Usually, there is an anti-rotation pin in the bearing outer race. These are small and can be overlooked, make sure it hasn't sheared off or anything like that.

I think i remember seeing some rings in the outer bearings that controll the position of the entire gear shaft. These should not be worn and check the groove in the housing.

Have a look at the shift fork for signs of wear or cutting on the flanks. Sometimes these can flex enough to touch the gear, but flex back. If the right hand one looks bent instead of flat, that could be the issue

Assembling the gears and turning them you may be able to detect if one of the teeth got bent (unlikely) if it makes a one per rev droning noise while spinning. Perhaps you can put your hand on top of the right hand bearing while spinning the shaft to see if there are any vibrations. - WATCH YOUR FINGERS. If you are using a power drill to turn the shaft, keep your fingers clear. No rings or loose clothing near spinning stuff.

One more thing to check is the little shaft spacers between the gears. Make sure they are not unduly worn.

Good luck - check everything and if you can't get those star/torx screws out, leave them in.

I like the cardboard bolt finder - I used plastic zip lock bags and wrote down the bolt pattern on the bag

Oh nearly forgot - if you have time, you can have a look at this - not the same bike, but they are all the same
http://s38.beta.photobucket.com/use...rt=6&o=0&_suid=136232380038901967912402868482

 

[TownsendsFJR1300]

Hi Adam, looks like you had a lot of difficulty getting those corroded bolts apart. That might be the hard part in all this adventure.

Do you know how the gears work? Just in case... 2nd gear is the pair on the right, furthest from the clutch. For the output shaft, it spins freely on the shaft and is only locked to the shaft when the right hand shift fork slides the dogs on 6th gear into the windows on second.

This is one area to look for wear. Are the dogs rounded on the ends or are the window edges rounded.

Another area to look is the bearings, which should turn freely and smoothly. They probably do. Usually, there is an anti-rotation pin in the bearing outer race. These are small and can be overlooked, make sure it hasn't sheared off or anything like that.

I think i remember seeing some rings in the outer bearings that controll the position of the entire gear shaft. These should not be worn and check the groove in the housing.

Have a look at the shift fork for signs of wear or cutting on the flanks. Sometimes these can flex enough to touch the gear, but flex back. If the right hand one looks bent instead of flat, that could be the issue

Assembling the gears and turning them you may be able to detect if one of the teeth got bent (unlikely) if it makes a one per rev droning noise while spinning. Perhaps you can put your hand on top of the right hand bearing while spinning the shaft to see if there are any vibrations. - WATCH YOUR FINGERS. If you are using a power drill to turn the shaft, keep your fingers clear. No rings or loose clothing near spinning stuff.

One more thing to check is the little shaft spacers between the gears. Make sure they are not unduly worn.

Good luck - check everything and if you can't get those star/torx screws out, leave them in.

I like the cardboard bolt finder - I used plastic zip lock bags and wrote down the bolt pattern on the bag

Oh nearly forgot - if you have time, you can have a look at this - not the same bike, but they are all the same
Slide1.jpg Photo by RichBinAZ | Photobucket

Great link with lots of excellent tips!

 

[TownsendsFJR1300]

Any updates Adam?

 

[AdamFZ]

Hi Guys,

Sorry been at work for the past 2 days and haven't had a chance to attack it but today i have.

Got the input shaft and gears out (had to drill one of the bolts off), along with the selector forks and barrel. Again, i can't see any signs of damage. There is the usual wear on the dog gears but everything else looks new.... :-( As i can't see what the fault is, its looking like i'm just going to have to put it all back together and hope the noise has gone ! :-(

As i'm waiting for some parts before i can move any further with rebuilding it, i decided to remove the broken header studs.... All played ball apart from the top center one !!! Even with a good soaking of penetrating oil and heat it didn't want to undo :-( Anyway, i'm going to fill it down to fit a socket and try again.

Also with a bit of penetrating oil and heat i got the cat off the manifold.... seems the gasket had welded them together !! Gonna give them a nice polish soon.

 

[FinalImpact]

One shift fork has contact up high. How did it get there?

Awesome PICTURES! What camera did you use?

 

[TownsendsFJR1300]

That one gear, (you took several pictures of), where the cog of another gear where set, did those edges look somewhat rounded off? There a gear WITH COGS (that may mesh with the above mentioned gear), they look somewhat rounded off and don't have square edges (where it would initially engauge) .

Was that 2nd gear or have anything to do with second gear?


And yes, excellent pictures!!

 

[Timon]

Hats off to you, good sir, excellent work and I hope you either find the source of the problem or it mysteriously goes away after the rebuild!

 

[RichBinAZ]

Hi Adam
In the 10th photo down... the shift fork with "5EB" and a 6 under it seems to have an odd mark just above the B - like the fork may have flexed and touched a gear. The forks apear straight to me and some marking at the chrome plated ends is to be expected.

The gear windows on that one gear appear a little rounded on one side and the polishing on the webs in between the windows is not severe, but some evidence of slip or a bit of difficulty getting it into whatever gear that is. If it was jumping out of gear you would know.

So what is making the noise when it is in gear?

Have a close look in the radiused root area between each gear tooth to see if there are any cracks starting. In both the smaller driving and larger driven 2nd gear. Should be the 2 gears furthest from the clutch. Those teeth look pretty substantial, but if there was a noise, it's worth a look. Probably have to wipe the oil off to get a good look, perhaps used an old small screwdriver to see if you can feel anything.

Well done with the studs, they can be a bear to get out. Have you tried driving a socket over the last protruding stud. I was able to get some nasty torks bolts out one time by driving a socket over the smooth OD, then turning it. It has to be a really tight fit though.
Rich

 

[TownsendsFJR1300]

Hi Adam
In the 10th photo down... the shift fork with "5EB" and a 6 under it seems to have an odd mark just above the B - like the fork may have flexed and touched a gear. The forks apear straight to me and some marking at the chrome plated ends is to be expected.

The gear windows on that one gear appear a little rounded on one side and the polishing on the webs in between the windows is not severe, but some evidence of slip or a bit of difficulty getting it into whatever gear that is. If it was jumping out of gear you would know.

So what is making the noise when it is in gear?

Rich

Missed that, GREAT CATCH!

I'd look real hard that fork is ever so slightly bent. It may be the reason those other cogs on the other gear had slightly rounded edges..

Any doubt, IMO, replace it, cheap insurance for where your at and all the work you've done...

Also, on one of the forks, it appeared an outer edge (not a contact point), had the edge rounded off as well...

 

[AdamFZ]

Was that 2nd gear or have anything to do with second gear?

No, that's 6th and the one on the shaft is 3rd. I will post up some pictures of the 2nd gears.

In the 10th photo down... the shift fork with "5EB" and a 6 under it seems to have an odd mark just above the B - like the fork may have flexed and touched a gear

That mark is tiny, its not deep, its just a light scratch. I can't even feel it with my finger or nail. I would expect a deeper scratch if it flexed and came into contact with another moving part I'll try and get a better picture of it.