Broken Penske Clevis.

[Fred W]

Fred, $26.62 plus shipping for a shoulder bolt and spacer collar?

Yeah, I saw that. The original all-in-one shoulder bolt was only $3.38. The new style (non-shouldered) bolt is $8 and the collar/spacer is almost $19? Yamaha is very proud of these new parts. Wonder what is so special about that collar that it costs so much? The hardened inner bearing race is only $8.

But, regardless of the price, it is a way to fix this Penske induced problem using Yamaha factory validated parts, if that is important to you. Penske should probably be the ones providing these parts (or the equivalent) to Penske shock owners.

 

[TownsendsFJR1300]

Send them the bill for the parts and an hour labor(or what ever you have into it)..

 

[TomInPA]

Send them the bill for the parts and an hour labor(or what ever you have into it)..

That way you can add your time and materials and a stamp to your losses. You ain't gonna see a check.

 

[exskibum]

Just outta curiosity, does anyone know what Penske is currently (subsequent to this issue becoming well known to them) providing and/or telling new retail customers and wholesale installers about mounting the affected end of these shocks on FJRs?

I have a GP rebuilt Wilbers on the FJR, but put a Penske on the last Blackbird, and it would be their point of sale actions around this issue that would bear on my decision to buy or avoid another Penske. What are they telling and providing to the likes of GP Suspension and Traxxion Dynamics?

 

[Fontanaman]

Eric responded to my email. Here it is unedited:

Jim,

I just returned from Daytona. I would have replied to you sooner but it has been hectic here.

We are looking to use a different clevis and bolt. It is actually the R6 clevis & bolt. We had a dealer doing an install on an FJR using the R6 clevis but they did not have a R6 bolt that wasn’t modified for a race bike. So they ended up machining the shoulder off the FJR bolt and using it with the R6 clevis. Our only concern now is the head size is different from the FJR to R6 bolts. The R6 bolt had a longer head than the FJR. We want to make sure it won’t contact the linkage or dog bones. I don’t believe it is an issue but we need to make sure before we make it a permanent fix.

We are working on getting a measurement between the dog bones just to be sure.

Thank you

Eric Trinkley

Motorcycle Department

Penske Racing Shocks

Custom Axis Shocks

150 Franklin Street

Reading, PA 19602

United States

Office: 610.375.6180

Fax: 610.375.6190

www.penskeshocks.com

www.customaxisshocks.com

From

 

[Mr_Canoehead]

Wow, that's an expensive fix compared to using the bolt from a GenIII AE model. Maybe you should point Eric to Fred's post and let him do the checking.

 

[HelzBelz]

Edited to removed redundancy from Jim's post above ( I got the same email from Eric)

I provided a tape measure measurement of 3 and 5/8's inches between the inside of the Dogbones, if someone can post a more precise measurement that would be great.

Also - I think this is a pretty work intensive fix for those of us with shocks already, I just think we need a new bolt.. I have asked if he can provide precised measurement of the 8975 shock's clevis (the bolt holes, the distance between the inside of the clevis forks and the outside of the Clevis forks. I think we can easily choose a new bolt from McMaster Carr that would either complement the existing spacer or replace it completely, right?

I spoke with Eric soon after, and asked why we wouldn't just source another bolt that specs out size wise, he said the R6 clevis and bolt would be the best fix, would fit perfectly (once they check the stock r6 bolt).. we should hopefully hear back soon.

We did also discuss the difference between the 8975 clevis and the others. The 8975 is beefier and can likely withstand the pinching better, but none of those clevises should be pinched. (I think we all know this).

 

[Fred W]

That doesn't sound like a very good idea to me. Changing out the entire shock clevis vs. just getting the correct sized bolt and spacer? Ridiculous.

The inside dimension distance between the two dog bones is 3.6". There is no way the shock mount is going to foul on the dog bones, plus it would never move up that high anyway.

A few more measurements I made today:

Stock "A" Shock Clevis Yoke Inside Width: 1.190 - 1.202" (the yoke legs were a bit slightly splayed)

Relay arm shock pivot inner race length: 1.175"

Stock "A" Shock Clevis yoke thickness: 0.195"

The outside to outside dimension on the stock yoke is 1.595"

It was previously reported that the stock bolt's shoulder width is 0.21"

So the relay arm inner race plus the bolt's shoulder is 1.175" + 0.21" = 1.385"

The distance on the stock shock from the inside of the yoke on the small hole side to the outside of the large hole side would be 1.190 + 0.195 = 1.385" Coincidence?

Now comes the problem:

The Penske yoke inside dimension was measured previously at 1.180 and the thickness of the yoke leg on the side with the larger hole was 0.225, so the distance from the inside of the small hole leg to the outside of the big hole leg is 1.180 + 0.225 = 1.405" When tightening the bolt, the head of the bolt will hit and need to compress the yoke legs about 0.02" before the shoulder hits the inner race.

The Penske total yoke width outside to outside is ~ 1.7"

The 3rd Gen ES Clevis yoke legs are .300" thick on both sides and the total width outside to outside is 1.7" (43mm), same as the Penske's. The 3rd Gen bolt is 58mm long. This tells me that the 3rd Gen ES bolt and spacer will work perfectly in the Penske Clevis. The 3rd Gen ES bolt is 10mm diameter and the A shoulder bolt has a shank that is 12mm.

Individually obtained parts would be a 12mm x 1.25 pitch x 60mm long bolt, a collar / spacer that is 12mm ID, 17mm OD and 10mm wide, and a 12mm x 1.25 pitch locking nut..

 

[Fred W]

I spoke with Eric soon after, and asked why we wouldn't just source another bolt that specs out size wise, he said the R6 clevis and bolt would be the best fix, would fit perfectly (once they check the stock r6 bolt).. we should hopefully hear back soon.

One more question for him: Are they planning on providing this solution to everyone with an installed Penske shock?

 

[HelzBelz]

Quick question Fred - Which Penske are you measuring? I assume the clevis measurements for the 8975 is different from the 8983 which is different from the 8987.

I don't have precision tools to measure my 8975, but I can probably find someone round here that does.

 

[HelzBelz]

I spoke with Eric soon after, and asked why we wouldn't just source another bolt that specs out size wise, he said the R6 clevis and bolt would be the best fix, would fit perfectly (once they check the stock r6 bolt).. we should hopefully hear back soon.

One more question for him: Are they planning on providing this solution to everyone with an installed Penske shock?

I did ask him that, and he did say yes. I immediately thought about how much down time that might mean to me awaiting a new clevis to be put on my shock.... Montana riding season is short, and we could have had this done during the winter...

I also just forwarded him your notes, and your analysis that the gen3 ES parts might solve our problem. They have a dealer trying to fit the R6 stuff to the FJR right now, but they do not have an R6 bolt on hand. I suggested that if that dealer has an ES on the floor, they could pull those parts and try it out. (If that works great..right?)

 

[Fred W]

Quick question Fred - Which Penske are you measuring? I assume the clevis measurements for the 8975 is different from the 8983 which is different from the 8987.
I don't have precision tools to measure my 8975, but I can probably find someone round here that does.

I'm basing the Penske measurements off of those posted earlier on in this thread by Fontanaman, which appeared to be the 8975. I do not have my Penske shock here right now (my son has that bike up in Vermont). I made the stock parts measurements off an old 1st Gen A shock and relay arm, and the stock ES measurements off my 2014.

I would think that with the number of FJRs with Penske 8975's installed that replacing the entire clevis mount would be rather costly for the company to absorb.

 

[HelzBelz]

for the record, loosened the bolt on my 8975, for the first time since june... The gap re-appeared, lol:

https://www.amazon.com/photos/share/Sc67DNcdn473nN8tQWIRMgirwcwIykjxNPirI4c0jTT

 

[Fred W]

I'm fairly certain that gap is supposed to be there when the bolt is fully tightened, based on the parts dimensions. It is there on my 2014 ES because the bolt and spacer clamp the inner bearing race without squeezing the clevis yoke closed.

That gap gives the relay arm the room it needs to pivot on the bottom of the shock easily, without any restriction.

Some folks showed photos previously of the inside of their Penske Clevis being all scored up. This may indicate that the relay arm is getting clamped inside the yoke when it's compressed, which wouldn't be a great thing for the suspension performance. If it is, it would add a bit of uncontrolled mechanical damping.

Or it may just be that the relay arm has migrated to one side on the needle bearing, as mine has, and is just lightly rubbing the yoke.

edit - Also on the above photo, though it's a bit fuzzy, you can see that the spacer (on the right side) protrudes a couple of mm proud of the yoke. The flange bolt head is a darker color than the (apparently alloy) spacer.

I tired searching McMaster-Carr catalog for spacers but couldn't find anything that large in diameter.

I just went down and measured the relay arm shock end pivot inner bearing collar (p/n 90387-127W0-00).

It measures 0.666" O.D. and 0.476" I.D. In other words, the bearing race is the same size as the spacer we need. If one were to cut off a 9-10mm length of that collar it would be exactly what is needed along with a 10mm x 1.25 x 60mm bolt.

 

[Fred W]

More info on this clevis stuff:

The shock pivot bearing changed part numbers between the "A" and "ES" models. The A models relay arm bearing collar was always 90387-127W0-00, and for the ES and the new part number is 90387-10104-00. In Yamaha parts speak, the "90387" means "collar" and the first two numbers represent the inside diameter, so the A model has a 12mm ID and the ES has a 10mm ID.

Measuring an A model relay arm, and the smaller hole diameter of the stock shock yoke bears that out.

The A model bolt for that pivot is the special shoulder bolt p/n 90109-10024-00.

The threaded part is 10mm, but the shank of the bolt is 12mm, and the shoulder is 17mm. (see recycled photo below)

I'm starting to fully understand how the stock parts fit together, and why the shoulder bolt doesn't work right on the Penske clevis: The width of the shoulder is the same as the thickness of the stock yoke. The length of the shank on the shoulder bolt is the same as the inside dimension of the yoke plus the thickness of the small side of the yoke. When the bolt is installed on the stock shock the start of the threaded part of the bolt is right at the outside edge of the steel yoke, so the smaller side of the yoke is fully supported by the 12mm shank, and the larger side of the yoke is fully supported by the shoulder. When the 10mm nut is fully tightened it will only go on as far as the start of the shank.

The Penske yoke is thicker, so the shoulder is not big enough and the shank will not be fully engaged in the small end either, as noted by FontanaMan much earlier in this thread.

This means that any replacement bolt would need to be 12mm, not 10. And the spacer would have to be 12mm ID and 17mm OD, which is the same dimensions as the A model bearing collar (90387-127W0-00). A piece of the bearing collar could be cut to make a good spacer.

The ES bolt and spacer will not work because the small hole in the shock yoke is 12mm not 10mm. I'll go back and edit my prior post that suggested it would work.

 

[HelzBelz]

Nice, and I've just learned that I've reached my quota for positive votes for the day.

A longer spacer, is what is needed, but the bolt is not long enough in reality either. so a longer bolt with a longer shoulder is what we need. back to square one.

Simply shaving the inside of the head of the oem bolt certainly works, but I really just want a new longer bolt, with a longer shoulder, whose head wont contact the clevis before the shoulder contacts the spacer, AND that leaves atleast two threads showing after tightening the bolt.

I was wrong about McMaster, they do not have shoulder bolt with a 17mm shoulder that I could find.(?)

I do believe that Penske will figure this out, and that their resistance to just spec'ing out a new bolt is silly.

 

[John d]

To me, the easiest fix is in post #255.

I would agree, John, except your washers are a bit too big. You want the OD to be the same size as (or slightly smaller than) the OD of the shoulder of the bolt.

It's OK. My method locks the bearing collar at both ends, same as many shocks of the past. Everything that needs to move is free to move.

 

[Fred W]

The size washer that would be needed would be 12mm ID, 17 or 16mm OD and maybe 1 or 2 mm thick That is a common size for copper and aluminum sealing washers, like the ones used on hydraulic hose fittings (think brake lines). I looked in my parts bin and found that I have a few of those in both copper and aluminum.

While it wouldn't be ideal since the small end will still not be properly engaged, it would at least get rid of the flexing of the clevis that is causing the cracking.

A better solution would be the 12mm through bolt with the 10mm long 17mm OD spacer.

 

[HelzBelz]

Anything the puts clamping pressure on the bolt head side clevis (the big hole) is not the way the Yamaha engineers designed it. the only clamping should occur at the nut end of the bolt on the small hole side of the clevis.

The nut clamps the bolt shoulder to the spacer, and as long as the head of the bolt doesn't contact the clevis that is all that is needed. there will be that slight gap to allow freedom of movement. Adding a shim, no matter how perfect it seems, doesn't actually fix anything.unless that shim fits inside the 17mm hole, and keeps the head of the bolt from contacting the clevis.

edit: Which I think is what Fred said above at the same time I was typing.

(I am not an engineer, but I think rationally. )

 

[jammess]

This is an interesting thread and maybe someone else has already covered this base but could you not, with a file, simply file a couple thousandths off the outer side of the clevis where the bolt head contacts the clevis face? This would allow the bolt shoulder to go just a bit deeper into the clevis as the nut is tightened and contact the inner bushing a bit sooner thus relieving the strain on the clevis. With a micrometer you could determine exactly how much surface to file off or just use an inside micrometer and take off material until no further clevis distortion is measurable as the nut is torqued.