• Welcome to the Yamaha FZ6 Forums. Member registration disables ads and allows you to post and share. Register Here.

Broken my gears :-(

No, sorry nothing.

I'm still riding it as its my daily commute to work but not using 2nd gear. Driving cautiously....

I'm still planning to whip the engine out again but i think i'l just going to get a 2nd hand set of gears and selector forks rather than a whole engine.
 
Let the fun begin!!!

Are you replacing any of the main roller bearings (the two shafts run on) with new ones?

Re-reading your first post and no apparent damage to the gears would have me inspecting those bearings very closely. That would certainly explain the grinding (nothing running true anymore) and gear noise..
 
Last edited:
FinalImpact said:
Up there it was mentioned that the forks should be replaced. I don't see the shift forks at fault if they are doing their job. The linkage should center each of the gears such that when NOT engaged there is no contact from the adjacent gear. If this holds true and the linkage locks the gear into place NOT allowing it out of the selected gear and the INTERLOCKS DO NOT allow selection of two gears at once, your issue is somewhere else.
>> Obviously if you hammer on the shifter hard enough it may induce contact beyond the forks pad intended to move the gear. Its momentary and not systemic of the noise being heard.

I have a theory; the abrupt gear engagement displaced the bushing to a point of distorting it and the gear(s) (include mating gear) no longer spins concentric under load.
Without a load the OIL easily centers the gears on the shaft and they FEEL FINE but they are not. With a dial indicator you can measure the deflection and run-out of the suspect gears. IT MUST BE DONE WITHOUT OIL.

The bushing is softer than the gear and potentially deformed making the gear set deflect under load. Is it worth checking?? Is it worth replacing the bushing or are you better off throwing in a used gear that was married to another box? Personally I'd measure it but thats just me.
Click to expand...


In this picture: I'd bet if you had some inside micrometers (bore gauge) you could measure this bearings interior in multiple places and find that the babbit deflected during the big crunch (its 2nd gear).
However, With a skim of oil and hand pressure you will never feel the "flat spot" on the inner bearing and it turns freely, but under load it deflects the gear contact pattern making noise as its not running in a perfect circle.

Slide3.jpg


I wish you luck with the new box of parts....
 
Started it today. Only removed the engine, will do the gears on Tuesday.

Took me just over an hour to remove the engine, not bad eh :cheer:

I'm not going to bore you all to much with loads of pics again as you've seen it all before:

Bish....


Bash....


Bosh.....
 
Thanks for the update. A favor please?
Snap a couple different pictures of the throttle bodies, fuel rail, an all that stuff.
So is the plan to drop in that used gear as one unit?
Thanks in advance!
 
Well, got the gearbox stripped but stuck now as I don't have a inner bearing remover to remove the input shaft far end bearing so i've ordered one:




 
You work quick!!!

Question, I noticed you had the main crankshaft bearing caps removed, is that necessary?

Or is the other half of the block holding in the opposite half of the bearings/ bearing caps?
 
TownsendsFJR1300 said:
You work quick!!!

Question, I noticed you had the main crankshaft bearing caps removed, is that necessary?

Or is the other half of the block holding in the opposite half of the bearings/ bearing caps?
Click to expand...

^^
It would be a bad sign if the shell fell out out of the block as they are supposed lock in thus it is normal for bearing to stay in the cap/block and NOT on the journal.

Of greater concern is the sealant in the oil passages. An exposed mating perimeter needs sealant. The interior does not but I have NOT read the manual to confirm Yamaha said ZERO, but too much is a bad thing and could plug feed port and starve something of oil. Adam, I just don't want you to induce a problem in this area. You make good progress! Good Job!

Thanks for the pictures Adam.
 
FinalImpact said:
^^
It would be a bad sign if the shell fell out out of the block as they are supposed lock in thus it is normal for bearing to stay in the cap/block and NOT on the journal.

Of greater concern is the sealant in the oil passages. An exposed mating perimeter needs sealant. The interior does not but I have NOT read the manual to confirm Yamaha said ZERO, but too much is a bad thing and could plug feed port and starve something of oil. Adam, I just don't want you to induce a problem in this area. You make good progress! Good Job!

Thanks for the pictures Adam.
Click to expand...

+1 on the bearings not falling out however they should fit snug in the engine case unless the case is worn/bearing spun, etc...

I just looked up in the 07-09 Yamaha manual for S&G's, (Page 5-58), it specifically states "NOT to have sealer come within 2-3mm's of the crankshaft journal bearings".

This makes sense as ALL the journals are literally INSIDE the engine. Even the outside jounals have left and right engine cases to keep engine oil in the engine.

As tight as newer engines are, I suspect the little bit of oil loss where the bearing halfs mate is very little and taken into account by the designers. As we all know, the FZ6 engine really doesn't have any lubrication issues.

Back to the thread!!
 
Last edited:
Thanks for the replies.

I can assure you that that little groove on the right hand side with sealant in it isn't a oil passage. There are no holes in it. And as you can see, the others are all clear and were all clear.

I was very careful when applying the gasket sealant.
 
ARSE :banghead: a crankcase bolt has snapped !! It wasn't even done up to the required torque !



Anyway, i got my new tool and got the bearing out:






Oh and here's what my information says about the sealant:

 
Last edited:
The Yamaha manual doesn't go into detail as the Haynes does re where to apply the sealer, "just the mating surface".

I wonder why the have sealer on the one little spot right in the middle between the crank and the transmission?

That bolt that broke, with the shoulder, I assume it goes into a special hole? Maybe for alignment purposes, just curious..

Also, like the Yamaha Outboard engines, they call for regular motor oil on the threads.


BTW, wish I lived nearby, I'd love to be there watching and learning hands on... Excellent experiance potential... (Not quite the same with pictures and a tutorial but very interesting IMHO)..
 
Last edited:
You must log in or register to reply here.

Similar threads

grcamna7
08' FZ6 S2 I want easier clutch action
Replies
9
Views
671
grcamna7
grcamna7
J
Stalls When Put In Gear
2
Replies
37
Views
3K
tuning-forks
tuning-forks
Y
Gear foot lever too high
Replies
5
Views
1K
agf
agf
C
Need Help New rider & bike questions
Replies
6
Views
1K
csnowden
C
Requin
Red calves, literally.
Replies
17
Views
982
Requin
Requin
Back
Top