Broken Gears 2011 EC300R

[booth]

So after completely redoing my 300 from scratch, it ran beautifully, then one run, pinned 5th, flat out on a massive climb, I shifted down to 4th and the 3rd, when I grabbed third, the bike seemed to "lose" power and slowed dramatically, as I can to a complete stop I heard a metallic clunk sound.

Turn around and go down the hill, by the time I get to the bottom, everything seems to be working fine,except fora slight clicking noise in third and sixth.

I strip the motor completely and find this:





The opposite gear set the one set of teeth have tiny chips missing.....


Any ideas as to why this happened?
Also what gear number has the teeth missing, is that third gear?

Any input would be appreciated please.

 

[shang]

That looks like third to me. The 3/4 set is one piece I believe. I just replaced a gear set in an 06 I picked up and it had two teeth missing from 4th gear. The cause of the failure was losing the chain guide, then throwing the chain, then the chain bound up under the CS sprocket locking up the trans during a 4th gear run. It's too bad you broke the same gear as mine. If it were any other gear I could send you my set.

 

[booth]

That looks like third to me. The 3/4 set is one piece I believe. I just replaced a gear set in an 06 I picked up and it had two teeth missing from 4th gear. The cause of the failure was losing the chain guide, then throwing the chain, then the chain bound up under the CS sprocket locking up the trans during a 4th gear run. It's too bad you broke the same gear as mine. If it were any other gear I could send you my set.

Yep still worried about what caused the failure in the first place, so worried I replace them and the same thing happens.

Hows your bike after replacing gears?

We have a local company here, that can repair or make new gears, so will send it off to them for repair.

 

[shang]

I have only ridden it up the road. I bought it as a spare bike for friends or family. My 2013 hasn't ever had any problems though, and I beat the crap out of that poor bike.

 

[Jacob 'Berg]

Yep still worried about what caused the failure in the first place, so worried I replace them and the same thing happens.

Hows your bike after replacing gears?

We have a local company here, that can repair or make new gears, so will send it off to them for repair.

Check your shift forks for wear and make sure that the forks as well as the shafts are true before re-assembly. I would replace all of the bearings in the gear box as well.

 

[Leo]

Look like half teeth broke and other half is ok. Can be bad contact point due mishift or bend forks?

 

[booth]

Look like half teeth broke and other half is ok. Can be bad contact point due mishift or bend forks?

Shift forks etc all look good will put them on a surface plate to check, just weird to me how it actually broke?

 

[booth]

Check your shift forks for wear and make sure that the forks as well as the shafts are true before re-assembly. I would replace all of the bearings in the gear box as well.

All the bearings in the motor were replaced when it was split, so they are all brand new SKF bearings

 

[booth]

Also took the gear sets in,and the local company here will charge me less than US$30 to repair both gears, so pretty happy with that, and I will have them back by Friday, so not all bad news....

They say will be as strong as original

 

[Jacob 'Berg]

All the bearings in the motor were replaced when it was split, so they are all brand new SKF bearings

That was before all those little bits of gear found there way into the gear oil...just sayin

 

[gasgasman]

Also took the gear sets in,and the local company here will charge me less than US$30 to repair both gears, so pretty happy with that, and I will have them back by Friday, so not all bad news....

They say will be as strong as original

That's not good, seeing the original broke.

The original gears probably broke due to improper heat treatment.

 

[shang]

Improper heat treatment is kind of what I was thinking too.

 

[booth]

Ok, so I got the gears repaired and have this weekend tried to re-assemble asI have been busy at work.

I know have a problem I cannot understand.

When the cases are snapped back together, the clutch input side of the gear sets, turns two turns and locks up, the counter sprocket side rotates freely.

This is how the manual states the gears should look assembled:


This is how my counter sproket side looks:



This is how the clutch input side looks:


I am confident enough that I have assembled the selector mechanism correctly and the shift forks etc are all good etc.

Can anyone please advise me as to what the problem could be?

 

[stabak]

if I remember correctly on the fiche one gear goes the opposite way part #17 or 18 ??? Had the same trouble...

 

[booth]

if I remember correctly on the fiche one gear goes the opposite way part #17 or 18 ??? Had the same trouble...

I am sure that is correct?

Anyone else care to venture a guess?

 

[gasgasman]

You have two gears (ratios) engaging at the same time.

 

[booth]

You have two gears (ratios) engaging at the same time.

How do I figure out which ones are incorrect then?
Everything looks right?

 

[gasgasman]

The shift drum has to just right.

Leave everything assembled in the right case, including shift shaft. Left case half off. Lay the engine on the right side.
Maybe start off in neutral and see if you can shift into 1st.