Replacing rear sprocket nut

[maz20]

Need to replace a stripped one, dealer doesn't have any in stock (and I kind of don't wanna wait for delivery for a little flange hex nut I can probably pick up at any hardware store!)

The manual says it's an M10 but doesn't specify the thread pitch (could be a standard 1.5mm, or a fine 1.25 and even a 1mm!)

*Edit: will be replacing the stripped one and the one directly opposite of it too just to prevent any rotational imbalances from "something not being exactly OEM..." (fortunately the FZ-07 wheel hub has an even # of nuts--else I'd have to replace them all!)

Edited August 25, 2019 by maz20

[maz20]

Lol everyone here must be strictly OEM-ONLY for these nuts/studs 

Turns out it's a common problem--even if we're not riding dirt bikes: 

Rear Sprocket bolts wont stay tight!! - YZ400F/426F/450F/450FX - ThumperTalk

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Ok, ive torqued, under torqued, over torqued, lock tighted, and tried just about everything but my rear sproket bolts still spin after about an hour of riding. Is there any fix for this so i dont have to...

*Edit: seems like it would be useful to have an FZ-07 "spare parts/bin" thread for riders to know what kinds of spares they should stock in their shops/garages

Edited August 27, 2019 by maz20

[DewMan]

Take one of the other nuts with you to the hardware store, they'll be able to match up the pitch for you. Make sure you get a nut of the proper grade to make sure it's strong enough. If you want to check for thread pitch at home, a pitch gauge will answer the question for you for a relatively small price. There are several styles of pitch gauge out there but this a cost effective example:

https://www.amazon.com/Deal】OriGlam-Thread-Cutting-Stainless-Metric/dp/B071H8GP18/ref=sr_1_1?keywords=OriGlam+Screw+Thread+Pitch&qid=1566920772&s=gateway&sr=8-1

 

Good Luck.

P.S. Perhaps a thread like this one is what you're looking for?

 

[maz20]

Well, that's part of the problem : ) 

My non-stripped sprocket nuts are stuck to the studs, so I can't take any out without also taking out the stud altogether!

I could just measure the thread of the open end of a stud with the stuck-on nut, but that would only be correct assuming the studs are threaded with the same pitch on both sides ; )

Likewise I cannot take out studs with the stripped nuts since there's nothing to rotate the empty stud out of the hub with. Or else I take off the rear wheel, take out the hub, and only after doing all that then take that hub to a hardware store and see what I can do there.

Would be great if I could avoid that whole procedure, since I can just replace those few loose sprocket parts on a rear stand without even having to take the whole wheel off and all that.  

So that's why I'm asking here, though I might be the first person ever here to replace the rear sprocket nuts with hardware-store parts^^

*Edit: I checked out your link, it's nice but lists OEM #'s only, not any general specs if someone were to get something compatible but non-OEM from a local auto or hardware supply store.

Edited August 28, 2019 by maz20

[maz20]

Some odd google searching took me over to

2015 Yamaha FZ-07 Motorcycle Parts

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Purchase 2015 Yamaha FZ-07 Motorcycle Parts from SportbikeTrackGear.com. Get the lowest price, free shipping deal, easy exchanges and no restocking fees - Guaranteed!

with a link to Driven® rear sprocket nuts specified @ M10-"1.25mm"

*Edit: with, of course, the usual disclaimer 

Quote

• ...
• Lightweight and an attractive alternative to stock heavy and bulky steel nuts
• Torque Specs: 10mm nut torque to 29 ft/lbs and use blue Loctite
• M10x1.25 pitch nuts fit most modern sport bikes with 10mm studs from Honda, Kawasaki, Suzuki, Triumph, and Yamaha
• ...

IMPORTANT FITMENT NOTE: The Driven Sprocket Nuts in this listing are 10mm x 1.25 and will fit most modern Japanese sportbikes. These will also fit Aprilia RSV4 models equipped with Forged Wheels from the factory. The BMW S1000RR and Ducati Models require a different size. While these fit a wide range of bikes we recommend measuring the sprocket nuts on your bike or calling Team STG before ordering if you are unsure these will fit your bike.

and torqued to 29 ft·lbs / 40 N·m instead of the service manual's 59 ft·lbs / 80 N·m

So, it looks like M10-1.25 is the likely size, conveniently available at your friendly, local Home Depot® for just 78¢/pair  https://www.homedepot.com/p/Everbilt-M10-1-25-Zinc-Metric-Flange-Nut-2-per-Bag-803928/204281764 

Edit#2: With the condition that this may not also be some sort of special, "self-locking" type of nut too though... so shopping around online you'll find stuff like https://www.amazon.com/Bolt-Motorcycle-Hardware-Metal-Locking/dp/B005PU94RK/ too

Edited August 29, 2019 by maz20

[maz20]

Also if anyone's interested I'm guessing 

M10-1.25 x 48mm OAL YZ 10.9 Cylinder Head & Manifold Double End Stud | Fastenal

 is the OEM-equivalent of the rear sprocket "stud", aka

Yamaha 90116-10048-00 - BOLT, STUD | Partzilla.com

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Buy Yamaha 90116-10048-00 - BOLT, STUD. This OEM part is guaranteed by Yamaha's limited part warranty ✓ FREE Shipping on qualified orders - Partzilla.com

albeit listed for "cylinder head & manifold" use, so maybe it has a lower tensile strength/rigidity rating?? (Or not, I'm not a metalworker, after all!!)

Edited August 29, 2019 by maz20