Time to replace front and rear sprocket and chain. Technical assistance requested please!

[TownsendsFJR1300]

First off, to say "most people failed" blaming folks vs the fastener (sure some probably over torqued), is by far ignorant (no personal attack intended)

Ignoring most of your previous posts, the studs hold the sprocket from spinning.


Back to your orginal BOLDED question.

Do you, or anyone else know what the hardness of that stud/nut is? Lets say it is the highest grade. (Of course we don't even know that)

Per your Fastenal chart, the MAXIMUM torque is 10 lbs lower. That is FACT, you posted it in BLACK AND WHITE which you requested. NO, it not nilly willie.

Using that chart vs the FSM, can you agree that 62 ft lbs MAY be more acceptable than 72? Not my opinion, nor anyone elses.

Most will probably be able to get 62 depending on the accuracy of their torque wrench, clean dry threads, etc.

And lastly, if their was no locking tab on the nuts, I agree, it would be considerably MORE CRITICAL of that fastener NOT to be too loose.

I do wish you read would read those links and numerous posts of 72 being too high and with your back round, come up with something acceptable as ALL the points others(including myself) have made DON'T mean squat, just your opinion..

Re me posting, for others to read the threads/posts and this entire thread and the other and let them decide, WHY DOES THAT BOTHER YOU??? If it prevents one person from destroying that hub, GOOD!!!!! One one of the threads I posted, the guy couldn't get the nut off as it was ALREADY stripped. Seems the previous mechainic/owner stripped it and left that way.

Your NOT the only one with an opinion that counts, and to ignore/discount everyone elses, is wrong.. You (and I), don't know everyones backround, engineering skills, etc, that's here..



Can you please address the sentence previously posted;

Using that chart vs the FSM, can you agree that the 62 ft lbs MAY be more acceptable than 72 ?


And lastly, Perhaps find a mechanical engineer, or better yet, contact ARP, send them a stud, nut, test the hardness of both, explain the specifics of the application, the type nut, etc and let them test. IMO, I think that woud be about as scientific as you can get. Do you agree to that???

 

[TownsendsFJR1300]

Something that occured to me later this (as I cut the yard) re how the 40ft lb # comes up (which I didn't bring up).

The exact same sized bolts (M10) are used to mount the engine to the frame as the sprocket (The frame pitch may be the same or different by one (1.25 vs 1.0) can't tell without disassembly .

BTW, I measured (from the outside), the approx amount of threads on the self locking nut vs a regular nut. The self locking nut has MAYBE 1 mm less threads, negligible..

Now, as most know, there is a total of FIVE bolts securring the engine to the frame. Three go thru the side "arms" and two longer steel bolts and steel nuts secure the rear of the engine to the frame. These bolts are also M10

The engine is a STRESSED MEMBER WITH THE FRAME and is held in(and the bike held together with these FIVE bolts.

All of these M10 engine to frame mounting bolts have a specified torque of 40 ft lbs per the FSM.

The sprocket carrier, uses NOT FIVE bolts but SIX. Again, ALL M10'S in BOTH APPLICATIONS...

Question, yes a different application, BUT, which bolts, the five or six take more stress?


*Now, the issue I have is, 5 bolts, holding the engine in the frame are torqued to 40 ft lbs.

However, a sprocket, held on with SIX same sized bolts, take 72 ft lbs...

Perhaps I'm missing something, but 5 bolts can secure, with 40' lbs can hold the bike /engine together. BUT, a sprocket, SAME SIZED BOLTS, [I]PLUS ONE[/I], needs 72 ft lbs???

Does anyone see anything wrong here?

COMMON SENSE, no charts, no pictures, don't need them, IMO, tells me WTF???? How does that work???


Just for S&G's,

If someone can pass on the exact thread pitch of the carrier stud and that of the engine bolts, I will personally e-mail ARP fasteners, give them the sizes, the use of the parts (not give them the FSM torque #'s for the nuts), a picture of my sprocket attached to the carrier and ask for thier opinion on what the torque, in THEIR EXPERIANCE, should be.

I would use e-mail so I can copy and paste so others can see the status of the e-mail/professional opinion (and check themselves should they doubt my credibility to this offer by myself).

Wether they answer or not, time will tell, but I do need the thread pitch, at least on the stud.

 

[FinalImpact]

Yes, in light of not knowing what Yamaha spec'd the components to, going with the ISO (International Organization for Standardization) for the size of the fastener, NOT the application; this seems to be a reasonable torque value i.e. 62 ft/lbs.
FWIW - thats 17% reduction vs 40% when dropping to 45 ft/lbs. See quote for details (62 ft/lbs at 75% proof load).

I participate here as I want people to be successfully. That said I try to explain Why there is a need to observe or do some action vs just saying 'do it'. Hence the reason I'm asking for details about "what was their process".

POINT: Any lubricant used or remaining (includes: antiseize & thread lock) for ANY REASON can lead to MASSIVE OVER TORQUE! The charts I found indicated a difference of 20 ft/lbs between oiled and dry. THAT'S HUGE. Looking at various interweb pictures one notices the failed parts are not as clean as they should have been. This alone could be the entire issue!


The "Chart" immediately referenced in the quote below is from our FSM indicating bare minimum torque for "General purpose fasteners" used throughout the vehicle like mirrors, fairing stay, side pods etc.

You have to keep in mind that the chart is for "General Purpose" and the quality of bolt used to say secure the side cover to the engine or the pod cover to the frame is a lower grade than those like the connecting rod or these studs in the hub.

Hence the words saying: use the written text on the topic vs that chart.

Speaking of charts here's another that has much more detail. Take a look. https://www.fastenal.com/content/feds/pdf/Torque-Tension Chart for Metric Fasteners.pdf

This is in ft/lbs, under DRY for 10mm bolt:
CLASS 10.9 = 53.2 ft/lbs for a clamp load of 8115 lbs
CLASS 12.9 = 62.2 ft/lbs for a clamp load of 9484 lbs

Much more conservative than the first chart found and they specified this: Clamp loads estimated as 75% of proof load for specified bolts. Meaning a standard bolt that meets that class still has some room to go before failure occurs.

So, does that mean yamaha has there own recipe for studs and nuts and if not, are they taking it to 90% or 100% or proof load? Also, I've seen this repeated SEVERAL TIMES; "using a torque wrench to tension a bolt introduces an error +/-30%. This has nothing to do with the Tq wrench!!! The process of measuring FASTENER STRETCH has something like a 5% error while using rotational force introduce 30% error in regard to tension applied (clamp force). Which further supports why most fasteners not being used to their potential. Because the engineering behind it INCLUDES A SAFETY MARGIN.

• Hence the reason why engine assembly of Head bolts, Rod bolts, crankshaft main bolts have yield to torque bolts which often times ARE NOT MEANT TO BE REUSED. Most of those are torque'd to say 30 ft/lbs (example) and then turn them 90 degrees for one time use to obtain the desired clamp force needed to secure the component(s).

Closing thoughts:
The install base is huge, 2003 - 2012 R1, R6, FZ6. All of the FSM's for the 3 bikes listed use the same hub and list the same tq spec. I checked! Are all of them wrong?
We know that the chain grease or thread lock could impact the final torque.

We don't know what population of people followed the process.
We don't know that other vehicles used the same fastener size, pitch, material, so why are they being brought into the equation. If they are the same, please provide some details.


Some light reading on thread shear.... The section about "Torque Control" should shed light on why OIL COULD BE THE SOLE CAUSE OF MANY FAILURES!
Quote from: http://www.fastenal.com/content/documents/FastenalTechnicalReferenceGuide.pdf

Pg 12 To determine the force required to strip the threads we must multiply the shear strength by the cross sectional area, which must be sheared.

Pg 22
Other types of shear joints depend on their initial clamp load as a resistance to slip. This type of joint requires that a frictional force be created between the joint members when the bolts are tightened. The shear forces have to overcome the friction developed by the clamp load, which in most cases will be far more than the actual “shear strength” of the fastener itself.

Pg 25
Whenever we tighten a bolt, a sequence of events takes place. By applying torque to the head, or the nut, we turn the fastener being torqued. This action stretches the bolt (similar to a spring) and creates a tension in the bolt. In most cases it is this tension or preload that we need to make a fastening. By controlling torque, turn, or stretch, we can control the buildup of tension. The closer we approach direct control of tension, the more accurate and expensive the method will be.
Some options for tension controls during assembly are: Torque Control, Torque and Turn Control, Stretch Control, and Direct Tension Control. These methods vary substantially in cost and accuracy.

Torque Control
One of the most common terms involving fastener installation is “torque.” Often a torque value is specified for a given application, and with the use of a calibrated torque wrench, this torque value can be obtained. What must be realized, however, is that this reading does not indicate the bolt tension directly.
Rather the torque reading is only an indirect indication of our desired tension.
A major question today is how much torque should be used to properly tighten a fastener. As simple as this question may seem, the answer depends on a variety of factors. It is estimated that roughly 90% of the input energy is lost in overcoming the mating friction under the head and between the thread or nut and its mating threads. Consequently only the remaining 10% of input energy is turned into bolt stretch. Bear in mind that this is an oversimplification of what may actually happen, since no consideration is given to the various forms of heat and strain energy introduced into the system.

 

[TownsendsFJR1300]

As I posted in a very early post, my Yamaha OB engine, same exact drain plug (pitch, size, etc) as the FZ is spec'ed at 20ft lbs. vs 30 ft for the FZ and FJR oil drain plugs. Why?

Why the difference? All are drain plugs, to get it bone dry with no oil residue is about impossible however they are spec'd 10 lbs lighter (20 vs 30, big difference at lighter loads). One manual is correct, the other, obviously not.

There have been many posts here of cracked oil pans from the drain bolt. The FJR design is different and the plug goes upward. The pan doesn't break, the "threads go away". (insert/helicoil time)

Something I learned when I had my Goldwing (and it was in the shop, warranty work) and makes a lot of sense why the #'s DON'T GET CHANGED, better parts installed, etc. Now this is from the service manager and makes complete sense;

If Honda, Yamaha, etc, screws up in the manual (ie, CC on the crankshaft doing a valve check, or breaking an oil pan going to 30 ft lbs, its obviously printed wrong.

THIS IS MOST IMPORTANT AND WORTH THE READ;
IF, this is a big IF , the manufacturer updates the manual for the new torque #'s, rotation, etc, their now LIABLE for all the previously damaged oil pan's, sprocket hubs, etc and open themselves up to major lawsuits.

$ is the bottom line. Don't change the spec, fix the FSM, NO LIABILITY.



The FSM is still being sold with the improper direction of the crankshaft for valve checks, 30 ft lbs on the drain plug (again FZ vs the OB same parts is 20 ft lbs).

For instance, unless its an issue/failure occuring while underway, (TPS) it likely won't be addressed/re-called.

The stripped hub, there's no liability there, the wheel is off, its an inconvienance. Yamaha WON'T be sued as the bike isn't dying in the middle of the roadway..

Same with the valve check, worse case scenereo, the mechanic screws your engine up in the shop as he followed the manual to the letter and didn't use common sense and turn the engine in the normal direction.. Yamaha's not on the hook
for anything.


ie, GM put out cars for a decade knowing the ignition switch was faulty. It was cheaper to pay millions for folks that died vs just fixing the problem!!!

 

[Puttin Along]

Wow, what a mess I started! Sorry! Hey from a newbie stand point, just 40lbs is a lot! Bud helping me has years of experience and used to race. He said don't worry about it it's plenty tight, centrifugal force helps hold em on with the lock washers it' not going anywhere. I'm no weakling and just 40lbs pulling on a wrench felt like a lot! If I die in a wreck from failure of these bolts I will come to you all in a dream! Lol, gonna prob ride Shady TN tomorrow too!

 

[Carlos840]

Some light reading on thread shear.... The section about "Torque Control" should shed light on why OIL COULD BE THE SOLE CAUSE OF MANY FAILURES!
Quote from: http://www.fastenal.com/content/documents/FastenalTechnicalReferenceGuide.pdf

I don't want to start taking side because i think both you and Scott make valid points, but after seeing the way oiled threads affect torque i cannot help but think that this could be a huge part of the problem.

If you take into account the fact that those bolts will be covered in chain lube and road grime and that most people will not take the time to clean them properly before putting them back on i think we have a serious suspect as to why this happens so often.

Like i mentioned earlier i cleaned all my studs and nuts with brake cleaner before putting them back and 100nm was achieved just fine.

I think the only way we can settle this is to buy 10 used sprocket hubs, leave 5 in used and greasy condition, and clean 5 with a good degreaser.
The bolts should then be tightened to 100nm according to the manual, we would then be able to see how the torque value can be achieved on both samples and if the greasy threads play a role in the stripping.

If both samples end up with stripped threads we know for a fact that the manual is wrong, if only the greasy hubs end up with stripped lugs we know this is user error.

Who is buying the hubs?

 

[TownsendsFJR1300]

I don't want to start taking side because i think both you and Scott make valid points, but after seeing the way oiled threads affect torque i cannot help but think that this could be a huge part of the problem.

If you take into account the fact that those bolts will be covered in chain lube and road grime and that most people will not take the time to clean them properly before putting them back on i think we have a serious suspect as to why this happens so often.

Like i mentioned earlier i cleaned all my studs and nuts with brake cleaner before putting them back and 100nm was achieved just fine.

I think the only way we can settle this is to buy 10 used sprocket hubs, leave 5 in used and greasy condition, and clean 5 with a good degreaser.
The bolts should then be tightened to 100nm according to the manual, we would then be able to see how the torque value can be achieved on both samples and if the greasy threads play a role in the stripping.

If both samples end up with stripped threads we know for a fact that the manual is wrong, if only the greasy hubs end up with stripped lugs we know this is user error.

Who is buying the hubs?

You'd need a dead on accurate torque wrench as well. A torque wrench reading slightly low or high would make the results inaccurate.

I think it's agreed upon by all, (and noted in the FSM) the threads should be dry (with no oil and grease) as that will definitly affect the torque reading and you will overtighten..

Condition (oil or clean) of the threads and the accuracy of the wrench, especiallly at such a high # is absolutly critical.

Cleaning the threads, is easy enough, but how often do you have your torque wrench calibrated?

A mechainic by trade would likely do it often. I will admit, of my wrenches, I've never had them calibrated (all Craftsman-absolutly NOT top pf the line like a Snap on, etc). And, yes, they should be calibrated.

 

[TownsendsFJR1300]

Wow, what a mess I started! Sorry!

You didn't start anything, no need to apoligize. Its been discussed/argued before, several times, just as heated... Blah

Just something to be made aware of, especially the cleaning of the threads, an accurate wrench if going fully to 72, etc...

:thumbup:

 

[FinalImpact]

Some random thoughts:
The nuts have a washer which offers two primary benefits, it displaces load and reduces friction between the nut and sprocket when torque is applied WHICH is another reason NOT to oil it. This design doesn't need oil.

Torque wrenches:
Give this some thought. Lets say the wrench has a 10% full scale error so at 100ft lbs thats +/-10 ft lbs depending on which way the error goes. Most wrenches are better than this and under 4% typically closer to 2%. Even the cheap ones. So IMO its likely not the issue. The greater issue is the wrong wrench for the job.
- I fit in this bucket! Wrench A) tops out at 50ft lbs. Wrench B) at 200 ft lbs. Both read within 2% at full scale. I.e. 50 and 200. The problem is this; using that 200 ft lb wrench at 70 ft lbs, its far less accurate at 70 than at 200. IIRC it starts at 35 ft lbs where it has something like a 15% error. Please read this, it explains how tool with +/-0.2% error could read off by as much as 30% when used below the max setting. Link Fails copy & paste: "www.npl.co.uk/reference/faqs/what-is-the-difference-between-'-reading'-and-'-full-scale-reading'-(faq-force)"

Adding link content as quote:

What is the difference between '% reading' and '% full scale reading'? (FAQ - Force)

The measurement uncertainties associated with specifications for force-measuring devices are often expressed as a percentage of full-scale reading. This is not always the case, however, and sometimes percentage of reading is used instead and the differences can be very significant, particularly when measuring forces that are quite small for a particular instrument.

For instance if an instrument is specified to have an uncertainty of ±0.3 % of full-scale output, and its maximum force capacity is 5 kN, then the user can reasonably hope that if the instrument is used correctly, the value of force it indicates will be correct, give or take 15 N. But if the force being measured is, say, 500 N the uncertainty, expressed as a percentage of the force, will be ten times higher, that is ±3 %. Similarly at 50 N the force-proportional uncertainty would be one hundred times greater, or ±30 %.

The table below shows the uncertainties in the measurement of force, first given as 1 % of reading and second expressed as 1 % of full-scale reading to illustrate the difference; in the region marked with arrows, the device performing to 1 % of full-scale reading is unlikely to make a meaningful measurement.

{{Copy & PASTE link to see graphs}} But basically it goes like this: the example has 1000Nm wrench with a Full Scale error of ±1% . FS = Full Scale
So when set to the following, its percent of error from full scale is:
@1000Nm it could apply a force of +/-10Nm = 1010 or 990Nm
@500Nm its a 2% error from FS
@100Nm its 10%
@50Nm its 20%
@10Nm its 100%
@5Nm its 200%
Moral of the story is use the right tool of the job!

^^ Read that a couple times and let it sink in. Point/Example; use a wrench with a max reading of 100 ft lbs to tighten a fastener to 90 ft lbs and its pretty accurate!! A BAD choice would be using 250 ft/lbs wrench to tq a fastener to 25 ft lbs as it would introduce a 50% error... << WAG...


Look for edits....

• Folks - I understand this is TOO MUCH DETAIL!!! - But if we can use some Theory, support it with facts, (Scott took a hands on leap +5), we'll condense it into NUMBER based upon the evidence gathered. Its the best we can do... Thanks for being patient!

 

[TownsendsFJR1300]

OK, HANDS ON time!

NOTE; I would prefer to have a genuine Yamaha carrier, with the Yamaha studs installed with the Yamaha nut to perform the same test just for S&G's.

First let me begin by saying, what I performed was on an M10 bolt, 1.25 pitch. I'm not sure of the Yamaha stud is 1.0 or 1.25 thread pitch.

In one of the pic's below are some markings of the hardness of the bolt however someone please chime in IF they know the hardness (2 hash marks opposite each other, 4 total).

Nut, approx 1mm thicker than the Yamaha nut, NOT a locking nut, no markings (pic's didn't come out so I didn't post it)

The BOLT was securred in my heavy duty vise (as if the carrier). I placed an approx 5/16" piece of steel, in-between to simulate the sprocket.

A flat medium washer (not as heavy as the Yamaha washer-didn't have one) was placed atop that and the nut (mentioned above) installed (it was slightly wider than the nut).

Prior to the above, both the nut and bolt were cleaned with BRAKE cleaner, run up and down on each other to make sure nothing was in the threads and re-cleaned.. The washer was NOT lubed, the plate NOT lubed. Everything is spotless...

**Keep in mind, I do not know is these bolts/nuts are harder or softer than what's on out bikes** however, at least we "have a ballpark".


Now for the interesting part;

Using my Craftsman 1/2 drive , 150ft lbs torque wrench, NEVER been re-calibrated.

Now, lets put some load on this puppy, sneak up on it and see EXACTLY WHEN it FAILS and what fails (nut too?).




Get to 50, no problem.

Get to 60, pulling but it gets there..

Now I'm going up by increments of 1 lb until it fails.

Get to 70, still holding..

Get to 72, took it!



Lets keep going, 1 lb at a time,

Final lbs at which BOTH the BOLT AND NUT STRIPPED: 88 ft lbs.. You can see the damaged threads and pulled threads in the pic's

I did not have an extra set (of nut and bolt)to try doing the same test with a smear of grease /oil on the threads.


Should someone want to donate a spare hub (can be broke, doesn't matter) with at least 2 undamaged studs, I'd perform the same test exactly and then again without cleaning the threads..

If someone at home has a decent torque wrench and a spare hub and wants to contribute, its easy enoguh to do.. Your really only destroying the stud and nut. Removal of the stud may be difficult (reported numerous times, lots of locktite), however I can weld a nut to the damaged stud and easily remove it..

See below pic's.

Double click to enlarge.

 

[Wildcat_drvr]

Found a little something about torque values.
Dry vs thread-locker.
An article by Kevin Cameroon on Cycleworld.
I love to read his writings!
Locktite says to reduce torque values by 20%
If Locktite is used.
Here is the article, 403 Forbidden
More food for thought.
You can find tables of wet-vs.-dry fastener torques in places like Thomas J. Glover’s “The Pocket Ref”
If you have a Machinist's Bible; Machinery's Handbook-29th Edition of the Machinist's Bible.
It may have information of interest also.

Rich

 

[FinalImpact]

Scott,
Well that's something.... Good Job! :thumbup:
Not exactly apples to apples but a step in the right direction none the less!

I couldn't find what you were looking for but found this: ASTM, SAE and ISO Grade Markings for Steel Fasteners - American Fastener Technologies Corporation

 

[TownsendsFJR1300]

I was very surprised it went that high. The wrench seemed pretty accurate as each step up, I went up by one pound and would pull a little farther with the wrench before I got my click. I dare say, I could feel that bolt stretching at the higher end (60+).

Perhaps Yamaha wants that stretch (if it is indeed there) on the stud/sprocket (like a connecting rod bolt).

Even if we had a dead accurate torque scale, we still don't know what grade studs and bolts actually are on the bike (which will make a difference).

So any chart, would get you in the ball park, but we don't know the hardness grade of the actual stud/nut to apply to the chart.

Until an accurate torque wrench is applied to the actual parts, which are spotless clean, the same test done, I'd be curious as to how it compares.

We already know most will take the 72, some don't. Unless Yamaha is using a very cheap, soft grade, stud/nut, it likely shouldn't be a problem (from what I learned today, hands on).

I suspect, after today, oil/grease, or a very inaccurate torque wrench are the culprits to the stripping.

I would also, just as above, like to see how far above 72 we can go, just for S&G's or are the factory parts close to their limits of 72 (a cheaper grade stud).

Just for my own curiosity, I (as posted previously) would like to repeat the test on the Yamaha parts DRY and not so dry and see how far different you can push those studs..


IMO, when I change my rear sprocket, pulling on that wrench, I think I would stop at 50 or so (my opinion, no specific reason, 50 is very tight-again IMO). That is at least until I did further testing on a Yamaha carrier stud, etc...

 

[TownsendsFJR1300]

Scott,
Well that's something.... Good Job! :thumbup:
Not exactly apples to apples but a step in the right direction none the less!

I couldn't find what you were looking for but found this: ASTM, SAE and ISO Grade Markings for Steel Fasteners - American Fastener Technologies Corporation

The bolt I used had a built in flat washer (seen in the previous pic's, which I did NOT use) and the head of the bolt is slightly dished. Clamped in the vise as shown. I wanted a non-moving "stud" if you would, with the turning force on the washer and nut.

Both were pulled from my box of spare metric, motorcycle nuts and bolts. I suspect that bolt was fairly hard, the nut, medium grade but they both failed at the same time...

 

[Puttin Along]

Bout 80 miles today not dead yet! Our Snap On guy has the calibration dial checker mounted on his truck and wouldn't care if I checked another brand. Most prob wouldn't!