Front Sprocket Replacement - Need New Lock Washer?

[SirIsaac]

I finally took the plunge and bought a new front sprocket. I looked at the service manual and noted that it says to replace the lock washer, which looks to me like a washer with tabs that get bent up around the nut to prevent it from loosening. Seems like I have read stories of people's front sprocket coming loose, which makes me a little worried about re-using the lock washer. So, all you folks who have replaced your front sprocket, did you re-use or replace the lock washer?

 

[thethendi]

I replaced it. Ordered it from Ron Ayers with a few other parts I needed at the time anyway.

I also used Loctite when installing the sprocket to hopefully prevent the nut from coming loose.

 

[FinalImpact]

Its cheap insurance. Replace it!
There is a good chance the nuts final position when fully torqued could be its original position which means the tab will be re-bent right back where it was. This can lead to it cracking and breaking at that bend. Replace it!

 

[Kenward]

I guess I'll be ordering a lock washer soon...

 

[SirIsaac]

I guess I'll be ordering a lock washer soon...

Hey, that was going to be my line! (just kidding )

I replaced it.

Its cheap insurance. Replace it!

Ok, you convinced me. But now I am confused (quite easy to do.) I checked an on-line parts source, and the washer for the 2007+ models is part no. 90201-20023-00, called "washer, plate". In the exploded part fiche diagram, it looks like a plain washer. So I checked a 2006, and the part number is different, 90215-21290-00 and it is called "washer, lock." The picture in the diagram looks like the one in the service manual, with splines on the inside and little tabs. The big nut that holds the sprocket on also has different part numbers, and the pictures look slightly different if you look closely. So did they re-design the nut so that no lock washer is required? I'm so confused!

2007+ parts fiche, part no. 34:

2006- parts fiche, still part no. 34

 

[QuietEagle]

SirIssac,

I just purchased the washer and nut for my new countersprocket on my 2008 FZ6. I haven't looked under the sprocket cover yet, but the newer style nut would be typical of other Yamaha's (my WR250X at least), i.e. I'm sure the Parts Breakdown is correct.

You can see in the picture how the nut has a small, thin rim extending out from it. Once you torque it down, there will be two channels in the shaft and you tap the rim down into the channel. I've included a link to a picture from a Case Saver for the WR250X where you can see how the nut is staked into the shaft.

What the previous poster was saying is that, were you to use the old nut, it may end up with a fresh part of the rim over the channels, but it may also return to the same spot and bending the metal again would really weaken it.

I wouldn't order the plate washer, but it is a good idea to replace the nut. I ordered the washer because I had the same idea as you, but you can see it is just a flat washer that is reusable (for 2007-)...For the later models, the locking is done with the nut, not the washer...Hope that helps :thumbup:

This is a WR250X, but the installation will be comparable...

 

[FinalImpact]

SirIssac,

You can see in the picture how the nut has a small, thin rim extending out from it. Once you torque it down, there will be two channels in the shaft and you tap the rim down into the channel. I've included a link to a picture from a Case Saver for the WR250X where you can see how the nut is staked into the shaft.

What the previous poster was saying is that, were you to use the old nut, it may end up with a fresh part of the rim over the channels, but it may also return to the same spot and bending the metal again would really weaken it.

I wouldn't order the plate washer, but it is a good idea to replace the nut. I ordered the washer because I had the same idea as you, but you can see it is just a flat washer that is reusable (for 2007-)...For the later models, the locking is done with the nut, not the washer...Hope that helps :thumbup:


This is a WR250X, but the installation will be comparable...

Well said and the pic helps. Thanks!

I would likely add some Red Thread Lock to it if it were mine as added insurance.

 

[Kenward]

Hey, that was going to be my line! (just kidding )

I'm sorry, I just wanted to borrow it! :spank: Guess I should ask first. haha

 

[Kenward]

Looks like I'll be ordering a lock nut and washer soon...wait, can I say that?!

 

[SirIsaac]

...You can see in the picture how the nut has a small, thin rim extending out from it. Once you torque it down, there will be two channels in the shaft and you tap the rim down into the channel...

Thanks, that makes perfect sense now. I have encountered that type of nut before somewhere, maybe holding the bearings on the front wheel of a car I once owned. Pretty sure I re-used it that time, but this time I'll do things right.

Looks like I'll be ordering a lock nut and washer soon...wait, can I say that?!

By all means!

 

[abraxas]

I've had a front sprocket come off. Thankfully i was riding really slowly at the time. It happens. Try buying that nut too. Nobody keeps them in stock.

So, when you get a new front sprocket, you go get the locknut washer from yamaha, and you locktite the nut, and you fold the washer ON ALL 3 SIDES.

Trust me on this.

 

[upshiftoverdrive]

SirIssac,

I just purchased the washer and nut for my new countersprocket on my 2008 FZ6. I haven't looked under the sprocket cover yet, but the newer style nut would be typical of other Yamaha's (my WR250X at least), i.e. I'm sure the Parts Breakdown is correct.

You can see in the picture how the nut has a small, thin rim extending out from it. Once you torque it down, there will be two channels in the shaft and you tap the rim down into the channel. I've included a link to a picture from a Case Saver for the WR250X where you can see how the nut is staked into the shaft.

What the previous poster was saying is that, were you to use the old nut, it may end up with a fresh part of the rim over the channels, but it may also return to the same spot and bending the metal again would really weaken it.

I wouldn't order the plate washer, but it is a good idea to replace the nut. I ordered the washer because I had the same idea as you, but you can see it is just a flat washer that is reusable (for 2007-)...For the later models, the locking is done with the nut, not the washer...Hope that helps [emoji106]

This is a WR250X, but the installation will be comparable...

Its cheap insurance. Replace it!

You wouldn't happen to have a part number on that front sprocket nut for the FZ6 would you? I can't find the part through Ron Ayers or Boats.net for the life of me... I have a 2007, so I need the nut with the crush able metal ring at the end that hugs the counter shaft.

Thanks!

EDIT: Ah forget it, I found it. It is 90179-20011-00 for anyone that is curious. Part #35
2007 FZ6 - FZS6W Yamaha Motorcycle TRANSMISSION Diagram and Parts

Does anyone know if the 90179-20010-00 and 90179-20011-00 are different?

Partzilla says "Yamaha 90179-20011-00 Nut; New # 90179-20010-00"

So I assume the 20010 is a newer version but still the same thing?

 

[TownsendsFJR1300]

Make sure your output shaft (with the sprocket) DOES have the flat spots on it to peen the 07 nut over onto it (locking it).

I dunno if the S1 output shaft has that flat spot. If not, you need to stick with the OEM, S1 set up...

Plus 1 on the loctite with either set up..


(That WR nut is the same style as the S2 bikes, probably the exact same nut as well)




.

 

[zixaq]

For the S1:

http://www.bikebandit.com/oem-parts/2004-yamaha-fz6-ca-fz600ssc/o/m145559#sch299695

In BOTH this S1 diagram and your S2 diagram, parts 33, 34, 35 are the front sprocket, washer and nut.