Apparently everybody got memo except me - Fuji axle nuts s#ck big

[Pursuvant]

The original post didn't age well, it has been updated with latest. 2020-DEC.

Rear axle nuts on XSR7 / MT-07 have been failing pretty regular, without an absolute definitive reason. Imagine you decide to adjust your chain, you try to remove the rear axle nut, and it's seized. Below image is borrowed from another thread, you can read more about it here:

 

I initially blamed the Fuji axle nut and switched to Belmetric nylock nut. About 9K miles on Belmetric torqued at 68 ft-lbs w/ no anti-seize, I had another siezure.

The cause is discussed in this thread, suspicion has moved from Fuji nut, to axle material being soft, to lack of anti-seize, to "work stress" with high torque spec a compounding factor. You can read about all of these in this thread.

Edited 2021.01 I am running Fuji nut, drilled axle for R-cotter pin, anti-seize, and reduced torque to 52 ft-lbs (adjustment for the anti-seize reduced coefficient of friction). I don't know what the problem is, but my thoughts are 1) there's a high stainless steel content in the axle and it is galling the nut and/or (2) work stress. If I have another seizure, I will cut my own sliding block to replace the "axle cover". A new stiffened sliding block could mitigate #2 if the stock axle cover is flexing.

DISCLAIMER please never disregard Yami design & specs.

This is the Belmetric nut I tried but has now failed on my bike torqued at 68 ft-lbs, no anti-seize:

No longer recommended

NNH18X1.5YLW - Nylock Nut Class 10 Yellow Zinc [NNH18X1.5YLW] - $2.67 : Bel-Metric, Metric Hardware, Metric Fasteners, Metric Bolts, Metric Nuts & Time-Sert Thread Repair

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Bel-Metric NNH18X1.5YLW - Nylock Nut Class 10 Yellow Zinc [NNH18X1.5YLW] - M18X1.5, M18X1.50, 18mm Metric Fine Thread...

Edited January 1, 2021 by Pursuvant
Problem can not be pinned on Fuji nut

[cornerslider]

I too "didn't get the memo" .... I was fortunate enough to see the same exact failure on a friends FZ-07R (during a 5-hour endurance race) during a simple wheel change. It cost us NOT finishing the race, but I learned of the problem. I checked mine when I got home, and caught it in time before it got "real". I ordered a new axle, and then bought a titanium locknut from "Bellisimoto"- they are a site sponsor here. I haven't had any problems since. YAMAHA really dropped the ball on this one-

[michigan400]

Huh??? I think I have only adjusted my chain once or twice and didn't have an issue but I will keep an eye on this. I honestly can not remember if I actually torqued the rear wheel to spec or just tightened it by feel afterwards. Hopefully I just tightened it and didn't over do it trying to get a click from the ratchet.

Is it the nut (poor quality) or are the torque specs just too much for a fastener of that size / thread count? 

 

Release the memo!! LOL!!

[Pursuvant]

On 9/2/2020 at 12:14 PM, michigan400 said:

but I will keep an eye on this

M, you have to understand there is no keeping an eye on this. You will come out one day and try to loosen the OEM axle nut, and it will be seized to the axle. You did nothing wrong, these fuji nuts just fail anytime, never know when. Do you want to grind an axle nut off your axle?

See how bad it sucks, cause you don't know if yours will fail or not.

Maybe spray some wd-40 on OEM axle nut and exposed axle, to aid in getting it off one last time without the thing going bad b4 your eyes... 

Edited December 19, 2020 by Pursuvant

[michigan400]

I'll check it after I get the new nut. 1st time I've heard of this.

[Pursuvant]

On 9/2/2020 at 2:25 PM, michigan400 said:

I'll check it after I get the new nut. 1st time I've heard of this.

It will be ok. I've read if you lube the axle and nut good, you can carefully remove the nut. Others here can help with more advice.

Edited December 19, 2020 by Pursuvant

[klx678]

I did a low buck nyloc nut for around $3 after seeing about the poor selection of nuts by Yamaha.  

[blackout]

It's my opinion that's its because it's a metal lock nut and the axle steel is on the soft side.   So, yes, a nylon lock nut is a good solution.  

I spray WD40 on the threads to lubricate and clean the threads.   I have been lucky so far.  Knock on wood....

[Kiwii]

Glad I saw this post. Will be changing out the nut promptly. Previous owner of my FZ07 never serviced chain or adjusted slack. I’ve already done it once, with no issues on the nut. Hope that I will come off when I do the change. 
 

Is that replacement nut available in stores? 

[DewMan]

2 hours ago, Kiwii said:

Glad I saw this post. Will be changing out the nut promptly. Previous owner of my FZ07 never serviced chain or adjusted slack. I’ve already done it once, with no issues on the nut. Hope that I will come off when I do the change. 
 

Is that replacement nut available in stores? 

You probably won't find it in Home Depot or Lowes but you can probably find it in a local fastener (Fastenal or similar) store or maybe Granger.

[Pursuvant]

On 9/2/2020 at 11:40 PM, DewMan said:

You probably won't find it in Home Depot or Lowes but you can probably find it in a local fastener (Fastenal or similar) store or maybe Granger.

This Belmetric nut is no longer recommended - it too has seized under work stress

Edited December 19, 2020 by Pursuvant

[blackout]

Mc-Master Carr has them in Class 8, which I feel is suitable.  $12.15 for a 10 pack.  Part number 90576A106.

[ElGonzales]

Yes I've read of this several times.
Until now I use the original nut, but I clean the threads every time I loosen the axle with an old toothbrush, then apply a bit of anti seize ceramic grease and tighten to ~10% less torque than the user manual recommends to compensate the reduced thread friction.  I always forgot to add a M18x1.5 to the shopping cart, online and offline 

[klx678]

I got one at Fastenal.  

[shinyribs]

Weird. I love Fuji nuts. Nylon wears out, won't resist heat and usually looks cheap and bulky. But I also keep my stuff well greased and believe pressure washers are only for decks and vinyl siding

Edited September 5, 2020 by shinyribs

[shinyribs]

On 9/3/2020 at 3:15 AM, Pursuvant said:

DewMan, I had to search for a week to find that nut. Problem was the axle projects 19mm beyond the washer. That nut I found is 18.5 mm in "height". It fits perfectly, the nylon threads all get a grip and nut is flush with end of axle when torqued. I mean perfect fit (see pic above)

I found other nylock nuts but they were not hardened steel and they had too much "height", the nylock overhung the end of the axle.

The Belmetric I did find is perfect in fit and materials. C10 hardened steel, zinc coated, and 18.5 mm "height". That's the one I linked to in my original post.

I bought three of them, they are inexpensive, because they were hard to find I want two extra I can switch to fresh one every 3  or 4 years (if needed), if the nylock starts to look worn out.

Belmetric shipped them to me next day regular post, only took 3 days to get them in my hand. Would be great if you can find them at a local source, but if not these Belmetric are tough and perfect for this application . 

Are you positive that nut is properly engaging the nylon? I've never seen a nlyoc nut that could grab flush like that, and these axles have a few lead-in threads that reduce the diameter already.  Normal practice with nylocs is to have exposed threads beyond the lock. 

[ElGonzales]

11 hours ago, shinyribs said:

Are you positive that nut is properly engaging the nylon? I've never seen a nlyoc nut that could grab flush like that, and these axles have a few lead-in threads that reduce the diameter already.  Normal practice with nylocs is to have exposed threads beyond the lock. 

The company I work for in quality management (we are maker of maritime electronic systems for the worlds biggest cargo vessels and cruise ships) has the regulation, that there should be minimum 2 threads exposed beyond the nylon ring.
Once the nut was removed, it has to be renewed.

But on the other side, there are a lot of motorbikes that only use standard nuts with washer at this location. Never had a problem with loosened nuts.

[D.A.]

1 hour ago, ElGonzales said:

... there should be minimum 2 threads exposed beyond the nylon ring.
Once the nut was removed, it has to be renewed. ...

It’s hard to beat the Gilles Titanium Axle Nut with its built-in locking mechanism. It was one of my first purchases for my FZ-07. The $80 price tag was tough to swallow but it is purpose-built, works flawlessly, looks gorgeous, is bulletproof, goes on and off the bike quickly, and can be used over and over indefinitely without degrading the functionality.

(Just looking at the photo makes me drool!)

Plus, it’s an investment, meaning if you ever decide to sell your bike, you can remove the Gilles nut and resell it on eBay or this forum and recoup at least half the initial cost, making the price competitive with a nut that has to be replaced every time you replace or adjust the chain or remove the rear wheel. When you sell the bike you can install one of the nylock nuts discussed in this post so as not to saddle the bike’s next owner with the OEM nightmare nut. 

Gilles ACM Titanium Axle Nut M24 x1.5 for Kawasaki, BMW, and Yamaha models

Edited September 5, 2020 by D.A.

[Pursuvant]

On 9/4/2020 at 9:08 PM, shinyribs said:

Are you positive that nut is properly engaging the nylon?

Great question shinyribs, the photo can't show the reality. The axle projects completely through the nylock. 

This Belmetric nut is no longer recommended - it too has seized under work stress

Edited December 19, 2020 by Pursuvant

[Spatt]

Switch to an R6 axle.  Same part better material I don’t use the stock axles and swap to an SV650 nut without the lock.  

[Pursuvant]

6 hours ago, Spatt said:

Switch to an R6 axle.  Same part better material I don’t use the stock axles and swap to an SV650 nut without the lock.  

You want to speculate, the stock axle metal is soft and the fuji nut fails for that reason, it's flanges are gouging into the axle and folding under the nut threads?

That was blackout's opinion and i thought it a good one

[Spatt]

1 hour ago, Pursuvant said:

You want to speculate, the stock axle metal is soft and the fuji nut fails for that reason, it's flanges are gouging into the axle and folding under the nut threads?

That was blackout's opinion and i thought it a good one

Not sure but it almost acts as a MIM part.  I can’t see that being the cast but the older r6 uses the same part number and never had and issue with it. 

[firstyammerha]

last month, I tried to loosen this nut so I could adjust  the chain but the noise it made caused me to retighten it. I wasn't able to back the nut off a quarter turn. This was with liberal use of WD40 prior to putting the socket on the nut. There is another earlier post on this nut which touts the use of the SV650 nut as replacement for the stock nut and alerts anyone contemplating loosening this nut to be aware of possible problems.  

[Pursuvant]

1 hour ago, firstyammerha said:

 I tried to loosen this nut so I could adjust  the chain but the noise it made caused me to retighten it. I wasn't able to back the nut off a quarter turn. This was with liberal use of WD40 prior to putting the socket on the nut. There is another earlier post on this nut which touts the use of the SV650 nut as replacement

You are going to have to back that fuji nut off sooner or later. I would get your anti-sieze out and work it into the nut/outer threads.

I have the SV650 nut as well as what I recommended in original post - it's a castle nut and you can't do a cotter key conversion because the axle cover is a "well" the nut would sit down in, no room to slide a cotter key thru a castle nut.

Good luck with it I hope you can get fuji nut off, but if it's failed you may have a real headache (but only costs about $50 if you buy new axle, both axle covers, and the new BelMetric nut).

Somebody here on forum may have a clever idea short of using a grinder to cut it off - maybe ask question in a new post more members may look at and help you

Edited September 23, 2020 by Pursuvant

[clinical]

On 9/23/2020 at 4:38 PM, Pursuvant said:

it's a castle nut and you can't do a cotter key conversion because the axle cover is a "well" the nut would sit down in, no room to slide a cotter key thru a castle nut.

Do you think there would be room to lock it with Safety wire instead of a pin?