Jump to content
The MT-07 Forum

Torque Spec for the Bolt That Holds the Shift Pedal ON


GuybrushThreepwood

Recommended Posts

GuybrushThreepwood

Very confused about the  torque spec of this bolt since it seems different people call it different things. Looking at the excel document of torque specs, the "shift arm pinch bolt" is 10ft lbs. But is that the same bolt? The same bolt on the MT10 is 20ft lbs. I would assume they'd be the same, but not sure. I have a service manual for the 2014, and I've scoured the entire thing but I can't find any diagram that shows that bolt or its torque spec. Anyone know what it is? I've attached a diagram of the specific bolt. 

 

 

 

 

ped.PNG

Link to comment
Share on other sites

That's not a pinch bolt.  The arm on the transmission shaft has a pinch bolt.  36 is a pivot bolt, or something similar.  In any case, snug it up good without leaning on it overly, and don't fret about it. 

  • Like 3
Link to comment
Share on other sites

If it's an M6 thread you could look up the torque in a machinist handbook, but probably 72 in-lb (6 ft-lb) is adequate if dry.   For an M8 thread probably around 120 in-lb (10 ft-lb) would be adequate if dry.  These are below what most machinist charts would have them, but tight enough to stay put, if you are worried about it, put a drop of LocTite blue 242 hand tool thread locker on the threads.  Only need a dot of the stuff.

Here's a source for the manual, do the search and find what you want.  Click here

 

 

 

  • Like 2
Link to comment
Share on other sites

sweetscience

If the bolt is M6 use 22 Nm (16 ft/lb) with blue loctite.  Rearsets bolts are notorious for loosening from vibrations and feet wear.  

If M4 use 10 Nm.

Link to comment
Share on other sites

ElGonzales

22 Nm for M6 is way to much, even for the highest property class humanity ever invented. You have looked in the wrong row of the table :)

  • Like 1
Link to comment
Share on other sites

Triple Jim

Sometimes I wonder if the use of torque wrenches results in more broken bolts than using common sense  and feel.

  • Like 2
Link to comment
Share on other sites

1 hour ago, Triple Jim said:

I wonder if the use of torque wrenches results in more broken bolts than using common sense  and feel.

Was that a "click" or a "snap"...

  • Like 1
  • Haha 2
Link to comment
Share on other sites

5 hours ago, Triple Jim said:

Sometimes I wonder if the use of torque wrenches results in more broken bolts than using common sense  and feel.

I'm 43 years old and rebuilt my first engine, unsupervised, at 15 years old. I've been around gear heads my whole life. It wasnt until about 5 or so years ago that I started seeing everyone stressing over torque specs on mundane fasteners. If it wasn't a head, crank or flywheel bolt, you just tightened the thing and kept trucking. The amount of thread repair jobs going through my buddy's independent bike shop is insane. I don't know what the internet is doing, but it's great business for torque wrench salesmen and thread repair mechanics/machinists. 

  • Haha 1
Link to comment
Share on other sites

19 hours ago, Triple Jim said:

Sometimes I wonder if the use of torque wrenches results in more broken bolts than using common sense  and feel.

Really I would have to say "common sense" and "feel" for sure.   Nearly every kid that worked on a bicycle would round off the axle nuts by using an adjustable jaw wrench wrong or using the wrong size wrench because that's all they could find.   Then the ones that get into cars and motorcycles carry on the bad habits.   After rounding off parts long enough they finally learn to use the right size wrenches - including getting metric wrenches instead of trying to use SAE.   

Then after snapping off enough fasteners or having enough fall out they figure out that they might just need a torque wrench to do the job.  If they snap fasteners enough they might just learn about fastener grades and make sure they don't have 4.4 where an 8.8 or 10.9 is needed - aka know what should be there.  

That's my story and I'm sticking to it.  All the rounded bicycle axle nuts and the stripped axles, as well as the stripped fasteners on my first motorcycle, a Bultaco Sherpa T.  Learned a lot in the first year or so about having the right tools.  Bought cheap Japanese sockets (that turned out to be pretty darn good and still in use) and a few metric wrenches (one set was the offset ones made in India that appear to be the same as the ones sold at Harbor Freight).  Tools in the tool box increased as knowledge and skill increased. 

The use of torque wrenches started when doing a full engine rebuild on a Bultaco Sherpa S and then on a Suzuki TM125.  Used my father's 1/2 drive Craftsman beam ft-lb wrench.   A couple years later buying a 3/8 drive Powercraft beam inch-lb wrench knowing I needed a more applicable tool that would give a more accurate reading with the wider scale.

I also picked up the habit of using a torque wrench in a lot of places where others don't because of doing new motorcycle setup and prep.  I figure if I used a torque wrench on every fastener where a spec was given in the setup manual, and am known for doing so that I'd not be at fault if there was a fastener issue.   Even handlebars.   I don't always do so on my own work, but I've had bars slip because my common sense and feel wasn't good enough for the bars that had no knurling on them.  They slipped.  I did snap a fork cap stud while tightening them.  Didn't snap the others.  

I've never damaged a single fastener when using a torque wrench.  I also learned to look up torque values for fasteners according to machinery sites when a question comes up - like the subject of this thread.  No spec given, find the thread size and reference a machinery site for fastener torque values.  Last thing I'd want to do is have that shouldered shifter bolt fall out while I was riding down the road, because I relied on my "common sense" and "feel" instead of trying to make sure.  Might make for a long walk and a layover if on a trip, waiting for the part.   

I've learned that the owners manuals may not always be accurate, but the shop manuals pretty much are.   Must have more mechanically knowledgeable proof readers for the shop manuals.  I will say "common sense" and "feel" can give a feel for if a spec is too high.  If you sense it's too tight you stop and do some research.  There was a thread about stripping 14mm drain holes, seems the bike had an owners manual spec of like 29 ft-lb.  Doing a bit of research it turns out all the bikes referenced in the search had a spec around 15 ft-lb.  I also think to a person with some experience would have sensed that the torque was too high. 

How many of you have snapped fasteners with torque wrenches?   Do you know why they snapped?  Do you know why fasteners snapped while using "common sense" and "feel"?    

One of my favorites are the guys who will torque a fastener then give another quarter to full turn "to be sure".   Not talking about torque-turn, but regular torquing then giving an extra twist not called for.  

 

Which brings up the subject of torque-turn using bolt stretch for more accurate torquing than using a wrench alone.  The fastener is tighened to a low torque value to cut the friction factor to a minimal and mate the surfaces, then the fastener is turned a specific angle to achieve proper stretch to have the desired load.  The head bolts on my Chrysler/Mitsuishi Turbo 4 cyl had that torque-turn spec and the bolts were only considered good for one repetition after initial install, although I bought new ones anyway.   

 

Edited by klx678
  • Like 1
Link to comment
Share on other sites

50 minutes ago, klx678 said:

How many of you have snapped fasteners with torque wrenches? 

Not me - honestly I use torque wrenches more to know when to STOP rather than tighten more.

For something I consider important, like pinch bolts holding the fork tubes - I will use a smaller 3/8 drive torque wrench and use it as a reference point for when to stop. 

I have kind of a hybrid approach, remaining alert for when I think "enough is enough" especially going into aluminum. In other words, not blindly cranking until I hear the click. 

Oil drain plugs are a good example where you don't want to blindly torque to spec. There is a thread on this forum that has a consensus that the listed value is to high, and I agree.

The Yamaha MT-09 has similar high torque spec for oil drain (31 Ft Lb) with threads of people having stripped threads and having to use a helicoil to repair it.

A few years ago I noticed that the drain bolt torque specs for my various vehicles were all over the map. I researched what the common torque settings were for a large variety of motorcycles, cars, trucks, and decided that 20 Ft Lb was enough for any oil drain bolt, and that is what I use for all my vehicles. I have a 3/8 drive torque wrench (inch lb) that operates in that sweet spot, and again it is just a guide to help me know when to STOP.

I rarely pull out a torque wrench - but I have 3 of them in different ranges so they operate in a "sweet spot" of very low inch lbs, medium inch lbs, and larger Ft Lb for lug nuts, axle nuts, etc. And they are not Harbor Freight, one is a CDI (owned by Snap On) and the others are Tekton  which is a good compromise between price and quality.

Edited by Lone Wolf
  • Like 1
Link to comment
Share on other sites

GuybrushThreepwood

And for those of you wondering WHY I'm so insistent on knowing, it's because:

1. This is the shift pedal. If that falls off while I'm riding, I'm going to be in a very awkward situation. 

2. This is most important, but the bolt utilizes one of these washers. 

image.png.82a867c18fc0dc2968ccc7a3163df1f9.png

 

So this begs, the question, do I tighten it so much that this thing crushes or is it there to provide a gap? I don't understand why Yamaha, with all its bolts and torque specs, doesn't include on for a bolt that utilizes a washer like this. It SEEMS like it would be important. 

Link to comment
Share on other sites

Triple Jim

I expect the bolt is a shoulder type, so it can't be tightened so much that it flattens that washer.  A gap will be left by the shoulder, and that washer is there to prevent rattling.

Edited by Triple Jim
  • Like 2
Link to comment
Share on other sites

39 minutes ago, GuybrushThreepwood said:

... the shift pedal. If that falls off while I'm riding, I'm going to be in a very awkward situation. 

I used to have parts rattle and fall off my old Harley - most notably my air filter.

Never have heard of a shift pedal coming loose on any motorcycle.

Do you have the part removed at this point? Can you ID the bolt size? (any hardware store)

Partzilla does not specify the bolt size (Listed under "Stand/Footrest")

The factory manual does not list a torque setting. But it does list "General Torque Specifications"

If you are concerned, put some blue locktite on, snug it up, and ride.

Torque settings.jpg

Bolt.jpg

Partzilla.jpg

Edited by Lone Wolf
Link to comment
Share on other sites

ElGonzales

I just searched for this screw in two other aftermarket repair manuals. The tightening torque is not mentioned anywhere.
Oh before I forget: remember, it is not a steel in steel connection!  ;)

  • Like 1
Link to comment
Share on other sites

 

 

22 hours ago, GuybrushThreepwood said:

...so what's the answer?

I guess you didn't read the third post. 

 

 

21 hours ago, GuybrushThreepwood said:

Gutentight method it is then. Works for me. Thanks everyone!

And didn't realize you wanted to do a guesstimate method instead of a real torque value.  I wouldn't have wasted the time to give you an actual value

 

Link to comment
Share on other sites

GuybrushThreepwood
6 minutes ago, klx678 said:

 

 

I guess you didn't read the third post. 

 

 

And didn't realize you wanted to do a guesstimate method instead of a real torque value.  I wouldn't have wasted the time to give you an actual value

If it's an M6 thread you could look up the torque in a machinist handbook, but probably 72 in-lb (6 ft-lb) is adequate if dry.   For an M8 thread probably around 120 in-lb (10 ft-lb) would be adequate if dry.  These are below what most machinist charts would have them, but tight enough to stay put, if you are worried about it, put a drop of LocTite blue 242 hand tool thread locker on the threads.  Only need a dot of the stuff.

 

Yes, super accurate. Not a guesstimate at all. Thanks for that.

Link to comment
Share on other sites

@Lone Wolf  That torque chart is what I was looking for.   It is the level of values used by Honda when I was setting up bikes.  The spec is not the maximum the fastener can take, but rather the value used when threading into aluminum, like the forks, handlebars, and that case with the shifter shouldered special bolt for the shifter.   Maximum torque would probably strip out the alloy.  The M8 bolts used on the handlebars were spec'd by the setup manual at I think 10 ft-lb where the chart is showing 11, which isn't much difference.

Here is what is in the manual for my KLX250S.   They do have a lot of specific torques for specific fasteners obviously, but here is the catch all:

image.thumb.png.5aa804eec8ee6bb71e10d999b90dbb3e.png

  • Like 1
Link to comment
Share on other sites

27 minutes ago, GuybrushThreepwood said:

If it's an M6 thread you could look up the torque in a machinist handbook, but probably 72 in-lb (6 ft-lb) is adequate if dry.   For an M8 thread probably around 120 in-lb (10 ft-lb) would be adequate if dry.  These are below what most machinist charts would have them, but tight enough to stay put, if you are worried about it, put a drop of LocTite blue 242 hand tool thread locker on the threads.  Only need a dot of the stuff.

 

Yes, super accurate. Not a guesstimate at all. Thanks for that.

Machinery torque specs are maximums and must be treated as such.  My values were based on past experience in motorcycle setup in a shop and my own work.  I did some more leg work in spite of "gutentite" being good enough for you.  I wanted to know what the general torque values were, especially when fasteners thread into aluminum.  That and I couldn't find "gutentite" on my torque wrench nor online tools measuring it.

I found what I was looking for that backed up what I said and it was in my Kawasaki shop manual.  The chart for general torques with the fasteners threading into alloy in most cases.  I also saw a similar general list in a Yamaha manual, but I couldn't find it online.  

image.thumb.png.098bec34a667a3f2490760310e85bb48.png

In the manual there are exceptions and they are noted.  Like the M6 bolts used in the cam cap are spec'd at 104 in-lb, so clearly they have a required stretch nearer the maximum than average fasteners like the M6 fasteners that hold on he side covers.  So you now have some real values that are truly "gutentite".   They even give them in inch-lb values for the smaller fasteners.

You might notice how accurate I was in what I said in my "probably" values.  Seems I might have actually known what I was talking about - 72 in-lb for an M6 and 10 ft-lb for an M8.   A bit more precise than "gutentite".  Doesn't hurt to put on a drop of LocTite 242 hand tool thread locker though.  

 

Edited by klx678
  • Like 1
Link to comment
Share on other sites

GuybrushThreepwood

I get ya, I just have no idea if this is M8, M6, it's not listed anywhere and it's certainly not marked on the bag anywhere. I'm sure some guys can tell just by looking at it, but I cannot. 

 

I'm guessing since nobody bothered to note that anywhere and since the torque spec for this bolt doesn't exist, that it doesn't really matter all that much, just locktite, grease it up and tighten it up without hulking it down is what Yamaha expects me to do with it. I'm not going to bust out the torque wench if Yamaha couldn't be bothered to give a torque spec.

Link to comment
Share on other sites

5 minutes ago, GuybrushThreepwood said:

 I just have no idea if this is M8, M6, it's not listed anywhere

As I mentioned yesterday, you can take the part to any hardware store.

See what size nut threads onto that bolt. I realize this topic has been sort of beat to death, but if I wanted to know if something was M8 or M6, there is a fairly simple way to find out.

May help on a future issue because when it comes to working on stuff, there is always a level of knowledge that builds on prior experience.

Link to comment
Share on other sites

Triple Jim

Also, the outer diameter of the threads will be pretty close to the bolt size in millimeters.  You can hold a bolt up against a  metric ruler and see if it's M6 or M8.  A cheap caliper makes it even easier.

  • Like 2
Link to comment
Share on other sites

29 minutes ago, GuybrushThreepwood said:

I get ya, I just have no idea if this is M8, M6, it's not listed anywhere and it's certainly not marked on the bag anywhere. I'm sure some guys can tell just by looking at it, but I cannot. 

 

I'm guessing since nobody bothered to note that anywhere and since the torque spec for this bolt doesn't exist, that it doesn't really matter all that much, just locktite, grease it up and tighten it up without hulking it down is what Yamaha expects me to do with it. I'm not going to bust out the torque wench if Yamaha couldn't be bothered to give a torque spec.

Jim got here first with his comments so I'm backing them up.

Get a ruler marked with metric and measure across the end of the bolt.  You will definitely be able to tell 6mm from 8mm in an instant.  I don't always instantly know the size of fasteners and sometimes just want to make sure.

  

Side note:  If you have a bit of spare cash sometime, get a 6" caliper, they're really useful when working on your own stuff.  I use a dial type in inches, converting my metric values (divide by 25.4), but the electronic ones can measure mm or inches.  Harbor Freight ones are adequate for 99-44/100% of the measuring done on a motorcycle.  Just comes in handy.   If you do, just don't use a lot of thumb pressure, if it's touching it's right.  Using extra pressure will alter the value. 

I taught hand tool measurement in a machine tool manufacturer.  A light touch and knowing when it's in contact is the trick as an excellent machinist/engineer taught me when I was having problems measuring with a micrometer accurately...  before I was skilled enough to do it right and eventually teach it.

 

 

Edited by klx678
Link to comment
Share on other sites

Triple Jim
1 minute ago, klx678 said:

I use a dial type in inches, converting my metric values (divide by 24.5),

I think you mean 25.4.

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.