Broken Penske Clevis.

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Yes, thanks for the insight. But, God help us, what a sad and sorry state our society is in.

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What else falls in scope here? What about the advice to put a car tire on the back, or to run tire pressures higher than the manufacturer's specs, or what super bright auxiliary lights to run, or how to install spacers in the windshield to alter it's angle, or a zillion other things we discuss nearly every day? Aren't these all advice that could be latched onto by some law parasite bent on judiciary financial extortion?

What has happened to personal responsibility? When "Doc" decides to follow the internet advice to shim his own pivot bolt with parts he buys from the True Value hardware store down the road, based on the information he garnered from an internet forum, how is it anyone else's responsibility for his actions or his decision or any unforeseen result.
Let's limit it to the question I first responded to: designing and fabricating a fix for the existing adjustable height Penske clevis being used in conjunction with the OEM bolt assembly.

I'm not going to get into the politics of personal responsibility or the profit motive driving what you can safely do, Fred. There are worse and far more common abuses of the little guy in the legal system than the situation with Doc's widow. (Hint: they involve 800 pound gorillas using the expense of the system to bludgeon others into submission even when that gorilla is unlikely to win on the merits - a too frequent occurrence in real estate law.)

For this issue in this system, you CAN insure against the risk. You pay a premium that probably only makes economic sense if it is a part of a business, like an engineering firm or machine shop, but that is the choice. Having seen good hard working people who have been thrust into despair by the true negligence of others, this isn't quite so black and white that I'm willing to take empathy off the table or call all plaintiffs "law parasites." There is seldom a perfect solution to competing social objectives but it is what it is, and like I said, the process is broken enough that very often it doesn't work for someone. The real problem is one of human nature seeking individually beneficial results to the detriment of others; think "prisoners' dilemma" logical construct.

If you're not going to take the alternative routes of getting Penske to fix the defective part or to get insurance as part of your decision to offer the fix to others, that doesn't mean you can't publicly discuss the defect or what you think could be done to fix it. What has been done in this thread so far seems highly unlikely to be the basis for a negligent design or manufacture lawsuit. I'm not guaranteeing that result for the same reason that you cannot safely guarantee that your fix will avoid breakage with an apparently defective clevis design.

I think you can safely say that if it were your bike (or your son's), here is what you would do. You're neither affixing an engineer's stamp to a design nor offering to design or provide parts to anyone in particular, and you include a caveat that it's not intended to be adopted without review and approval of the design, fabrication and installation by an appropriately licensed and insured professional (like a shop that sells Penske shocks). Or you can be so absolutely certain that with your design fix, it is a true certainty that the Penske suspension set-up it goes on never can fail. In that case, it is your certainty that is your security.

As to other issues, OCfjr did indeed shoot this messenger when I noted a possibility that if a lawsuit was filed after an accident, an insurer might well attempt to blame the rider who installed the CT in an effort to get out of paying benefits. I believe we buried that hatchet later when he understood that I was not disagreeing with anyone's decision to dark-side. To be clear:

I do not think that discussing technical problems and possible engineering solutions is a problem for which anyone is likely to get sued. I do not think that anyone fabricating farkles is likely to find themselves in the Doc's widow scenario. I am cautioning those who might design or fabricate a fix, intended to be applied or used by others, for a part that might be critical to the safe functioning of the motorcycle.

Now for the disclaimer: I am retired, having inactive status with the state bar and am therefore currently prohibited from engaging in the practice of law in this state or others. Nothing I have said in this thread shall be construed as being reliable legal advice to be relied upon by anyone who might read it, and certainly should not be relied upon in the specific circumstances in which you might find yourself. Seek competent legal advice from a licensed attorney before taking or refraining from any action discussed in my posts here and elsewhere. Lastly, any comments or opinions expressed by me in this thread are worth exactly what each of you has paid me to read them - $0.00. And with that, I am done here, other than to read the enlightening opinions of the technically gifted forum members to whom credit for this thread should be given.

 
Here is your updated clevis. Please note:

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Bla bla bla bla.......................................... Just fix the damn thing and get on with having fun riding the FJR!

 
Lot's of interesting 'rabbit holes' to go down but..........

I find it interesting that Yamaha decided to move away from their 'standard' solution to this type of mechanical clamping arrangement.

Normally they go go for a sliding bushing to apply the clamping force to the bearing collar as in the shock upper mounting & the relay-arm forward mounting where it attaches to the bike frame.

If it were me I would go for that option:

Get a steel bolt/nut with similar properties to the original, long enough to clamp the bushing.

Get a steel bushing with an ID to slide on to the bolt and an OD that will slide in the larger hole in the clevis.

YMMV

 
Has anyone sent a broken specimen to Dave? A machined steel replacement would be on my Christmas list.

 
I like Donal's approach as well, although I suspect it's not all that easy to find a perfect match...

 
The frame end pivot of the relay arm (the one everyone has trouble removing) has a similar set-up to what Donal described. Item #26 in this 1st Gen parts breakdown.

It is just a sliding bushing slipped onto a regular (shoulder-less) bolt. When you tighten that bolt you are clamping the bushing and the bearing's inner race to the left side frame tab. The right side tab is a larger hole that the bushing can just barley slip through, similar to the shock's clevis. The bushing in that case is alloy, and it regularly seizes in the frame tab's hole, but since it is being used on the same relay arm, and so is subjected to the same forces, one might assume that the alloy is up to the task. I wonder if its outside diameter is appropriate to the shock clevis hole.

 
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The shoulder bolt is just a "pin" in this use, there is (should be) no actual clamping force from the bolt except the inner race being clamped to the small side of the yoke, and the nut is torqued pretty low. I don't see how shaving the underside of the head a little would weaken the part in use at all.

Curious: How did you shave the bolt --G? On a lathe or a mill of some sort?

Another similar solution would be to shave down the clevis yoke on the outside where the bolt head contacts, but that would have the deleterious effect of weakening the already fragile clevis yoke.

Disclaimer: I am not a mechanical engineer and can not recommend that anyone modify the suspension (or anything else for that matter) on their own bikes.

 
Does that weaken the "rating" of the bolt?
I suppose technically it could have but it really has no clamping force on the head. The bolt material seemed dead soft.

The shoulder bolt is just a "pin" in this use, there is (should be) no actual clamping force from the bolt except the inner race being clamped to the small side of the yoke, and the nut is torqued pretty low. I don't see how shaving the underside of the head a little would weaken the part in use at all.
Curious: How did you shave the bolt --G? On a lathe or a mill of some sort?

Another similar solution would be to shave down the clevis yoke on the outside where the bolt head contacts, but that would have the deleterious effect of weakening the already fragile clevis yoke.

Disclaimer: I am not a mechanical engineer and can not recommend that anyone modify the suspension (or anything else for that matter) on their own bikes.
Went down the street and used a friends lathe, used a small L/H carbide bit with a small radius. Put my little 1/4 travel indicator on the ways touched off, zeroed and took little .010 passes.

 
I'll have to go take a look at the Penske I pulled off of Old Yeller now. Over 100K on it and no broken clevis, however I should inspect it for any cracks.

Pertaining to exskibum's posts though, I am more concerned about how his arguments apply to those of us who host <edit> tech days. I can see already that the potential for nightmares could be limitless.

 
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George's recent post and the passion of this forum, in this thread in particular, to focus on an issue and solve it....is simply stunning. Thank you!
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So essentially if Penske narrowed the gap on the Clevas we wouldn't have to modify the bolt, correct?

Dave

 
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The Clevis yoke inside dimension can't be narrowed because it has to fit the inner bearing race. The reason the bolt shoulder is inadequate is because the OEM clevis is made from steel and is a thinner material. To get the required strength out of the alloy material that Penske used they had to make the legs of the yoke thicker, which them made the shoulder inadequate to avoid the head hitting the outside and clamping the legs of the yoke together.

Not to cast aspersions, but I really can't understand how the design guys at Penske missed such an important detail.

 
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