Come on, just go to Times Square around midnight on Dec. 31 and you will see lots of them. As a native New Yorker, it takes one to recognize one - and I've seen a lot of them.:bow1:
Why does Honda have us replace bolts?
- Thread starter SMSW
- Start date
Come on, just go to Times Square around midnight on Dec. 31 and you will see lots of them. As a native New Yorker, it takes one to recognize one - and I've seen a lot of them.:bow1:
-- Any literature on that?
Absolutely. Several sources. Here is Wikipedia, just as a start.
https://en.m.wikipedia.org/wiki/Torque-to-yield_fastener
Ive removed a million cotter pins in my life time. Not one had a loose nut under it. Have you ever found one?
As a private pilot I see some wired on nuts on easy to get to things like the propeller. Maybe one in a hundred fasteners have wires to secure them. But if they arent easy to get to....no wires. thats 99% of the fasteners on my airplane. The sheet metal screws that hold the inspection covers in place arent possible to wire in place. They dont use loctite on em either. Been flying since '83. Theres hundreds of sheet metal screws on an airplane. Never saw a loose one. Not one
No argument here.
If the fastener has enough preload, and the workloads, vibration periods and amplitudes do not exceed the preload, and if the fastener is only loaded in tension, there should be no reason for it to loosen. All the additional methods of securing the fastener (wiring, thread deformation, lock washers, Nylock, chemical locking, peening, cotter pins and castle nuts etc.) All exist as backups to the original preload.
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Agree. After reading Al-Hala's link and others, without an angle torque spec on this bolt, little chance of a TTY here. Not a typical application for TTY either.
jfheath
John Heath
Just to add a little more illumination or confusion to the issue of ALOC bolts - I went through the 'General Information' in the Shop Manual looking for other bolts that required a new ALOC bolt/screw to be fitted (Identified as 'Note 6' in my copy). Some may surprise you -
And yes, the instructions do say to fit a new handlebar weight mounting screw.
| Item | Size | Torque |
| Middle Cowl mounting bolts | 6mm | 10Nm / 7 ft-lb |
| Front Brake disc bolt | 6mm | 20Nm / 14 ft-lb |
| Rear brake disc bolt | 8mm | 42Nm / 31 ft-lb |
| Rear Brake Caliper Stopper Bolt | 18mm | 69Nm /51 ft-lb |
| Rear Shock Upper Mounting Bolt | 10mm | 42Nm / 31 ft-lb |
| Front Brake Caliper Mounting Bolts | 8mm | 31Nm / 23 ft-lb |
| Caliper Body B Bolt | 8mm | 32 Nm / 24 ft-lb |
| Rear Master Cylinder Mount Bolt | 6mm | 12Nm / 9 ft-lb |
| Pulsar Rings (both wheels) | 5mm | 8Nm / 6 ft-lb |
| Side Stand Switch Bolt | 6mm | 10Nm / 7 ft/lb |
| Centre Stand Pivot Stopper Bolt | 6mm | 12Nm / 9 ft-lb |
| Handlebar Weight Mounting Screw | 6mm | 10Nm / 7ft-lb |
And yes, the instructions do say to fit a new handlebar weight mounting screw.
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This is better than an Oil Thread...carry on gentlemen...
opcorn:beer8:
opcorn:beer8:
Yes. Most all the larger ones have an initial torque spec and then a further tighten sequence ritual. Some to the point of being almost scary. Crankshaft sprocket bolt, for example. The majority of the TTY bolts in the referenced brand I am most familiar with have a "necked down" area below the threads and all of them, even the smaller ones that aren't made that way have a slight different color from an (I assume) anti-corrosion coating on them. Those bolts are almost always in pristine condition upon removal. Most all quality replacement part venders I purchase from include these fasteners with the related parts in a "kit" form. Dealerships have a tendency to seldom replace many such bolts during required service work, probably because of poor parts inventory and the desire to get the customer done/gone. I have a large drawer full of them for use in projects that aren't critical applications.
BakerBoy
It's all small stuff.
@jettawreck... The slight different color on bolts often comes from a heat treatment process--that process removes residual stresses inside the part and make all the microstructure "the same" so that the neck area is of known, predictable yield strength. They may also have dipped the bolts (either quenching it while hot or dipping after already cooled) in a sealing compound so that the bolt surface isn't attacked--once the bolt is torqued down, any contaminants trapped along the bolt shank can become corrosive at elevated temperature and can easily diffuse into the yielded bolt shank porous surface. ...But all that is speculation as I don't know what that vendor's specifications are on the fasteners you mention.
BakerBoy
It's all small stuff.
Good info John.
I surmise that many of those replacements are oversights/errors on Honda's part. I've added a column of 'Relative Tension' to the above table based on the torque and bolt size, making the assumptions in the calculation that all bolt rotational drag loads and all bolt materials are equivalent (are in proportion to torque and diameter).
It appears that only a handful of those bolts have high relative tension (100%, 85%, maybe 76% and 74%, all shown in red). Those appear to be potential candidates for 'replace each time'. The rest of the list appear to be low-torque applications.
For all reading this: Use at your own risk. The above numbers are relative tension where I chose to call the highest tensile load "100%". The % numbers are not showing capability, but rather simply show resulting bolt tensile loads relative to each other for the purpose of this discussion.
Someone mentioned that certain bolts (head bolts?) can have deformed threads or be necked down somehow. Certainly any fastener like that should be replaced! And Ive certainly rebuilt engines with kits that include new head bolts. (although Ive never found any of the original head bolts with deformed threads)
Seems to me if you find deformed threads that indicates 1) the bolt was over-torqued on assembly or 2) defective for the application somehow.
Seems to me if you find deformed threads that indicates 1) the bolt was over-torqued on assembly or 2) defective for the application somehow.
No, that's not what they mentioned or meant. Go back and read it thru again.
Some TTY bolts have a section of the bolt below the head that is a slightly smaller diameter to allow the bolt to "stretch" in that area and keep the tension on the threaded parts. I could post a few pictures of examples from my stash when I get home this weekend.
You've given us the most logical reason why Honda wants the top bolt to be replaced and not reused. I've posted a picture of the top and bottom bolts below - the top bolt is the allen type with the acorn nut above it. Both bolts are within a couple of hundreths of a mm in diameter (threaded part too), and both get tightened to the same torque. I have to guess that they are made of different steels - its unlikely that the dull finish of the lower bolt is just a zinc coating to prevent corrosion.
What am I missing here? The top shock mount is pinned to the frame and the bolt squeezes the steel insert that is surrounded by the rubber bushing. The clamping force is unlike that of a cylinder head bolt, where bolt size is often an issue and the strength of the bolts resist the burning force of the gasoline. In other words, why did Honda use this nut and bolt (I accept it's a TTY bolt) and not a larger one - or a Grade 5 or 8 bolt? Why is this clamping force needed at all, when the forces from the shock are normal to the length of the bolt (i.e. a shearing force).
a purpose.
you're discussing a topic with a bunch of people who have no idea why Honda makes the decisions they do, and trying to guess at why something was decided 25 years ago on another continent.
If it makes you sleep better at night, replace the bolts that Honda recommends replacing. If you don't care, put the old one back in. How many ST bolt failures get reported here???
BTW, there's absolutely no reason a shock bolt would ever be a TTY bolt. Stretching it to its elastic limit would have absolutely no effect on forces normal to it (as you already mentioned). A TTY fastener is essentially a spring without any coils, it applies a force in the direction of the bolt, and zero force normal to it. You could use a plain steel rod with a cotter pin on both ends and achieve the same result as a shock upper mounting fastener. The only purpose the bolt provides is to keep the shock from slapping around horizontally in the mounts.
Well, someone feels strongly about the topic.
For me, I wanted to bring a possibly unknown type of fastening method to the attention of those that may not know of its existence, to spread some knowledge of what possibly the rationale was. That was my purpose.
I have gleaned considerable insight from people discussing various facets of the ST1300 from these forums, in part from the search for knowledge and a perceived drive to better the machine.
The fact we don't know something should not stop us from attempting to understand why something is, all comments about a little knowledge being dangerous acknowledged.
Having said that, I also understand some just want to ride, and this thread is of likely zero interest to them. I'd still buy them a beverage.
Whilst doing some research, I chanced upon the Honda Common Service Manual from a fellow (past) ST1300 owner's site. There is some good information on fasteners in it.
http://koczarski.com/ST1300/ManualsAndDocs/Honda_Common_Service_Manual.pdf
http://koczarski.com/ST1300/ManualsAndDocs/Honda_Common_Service_Manual.pdf