Double bugger!!!!

[Lucky]

Don't forget the carb issues...  ::)

BUT in a way it's good things happened the way they did, or else we might just be another R1 Forum!!  ;D ;D

[QBS]

Trust me.  I didn't forget the carb problems.  I just consider them to be seperate from the engine fundementals.  However, Yamaha providing a real live fuel filter would have been a really neat thing.  Think about it.  The V has self canceling turn signals which were extremely rare and wonderful at the time and even now.  But they wouldn't give it a fuel filter.  Sometimes common sense isn't common.

[Rikugun]

It's funny but I can't think of any Japanese bike that came with a fuel filter other than the petcock screen. As far as the other quirks go, many new models go through "growing pains". Honda's XR models with 2 carbs were a nightmare. They resolved it by going back to a single carb. Didn't the early Virago models have starter clutch issues too?  The first 740 four Honda's suffered from oil delivery problems to the cam & valvetrain. Some mid 80's Kawi 1000/1100's had crankshafts that shifted out of phase under certain conditions. There are many more. Eventually, all these problems were resolved. I'm sure if Vision sales had warranted continued production, their quirks would have been fixed as well.   But as Lucky pointed out, we'd have a far less exclusive club then!       But getting back to the starter clutch dilemma...

For discussion sake, what if a different approach were taken. What if Yamaha's original plan had been executed properly. What if the original screws were removed, thoroughly cleaned, loctite applied and torqued to spec. So far we've added thread locker which I believe wasn't used at the factory. Then, using the appropriate center punch, continue the original staking to involve the threaded hole as it should be. To move the bolt material into the rotor material such to create a matching deformation in the rotor's threads. A ball and socket or male/female component if you will. This would effectively lock the screw in place.

Human nature being what it is, I'd be disappointed if some didn't immediately scoff and suggest the mushroomed bolt method is the only way to go. "It's been done this way for years and is proven." "It's just the way everyone does it so it must be the best way."  "Back in '84, a Norwegian Yamaha tech named Yodin got all medieval with hammer and punch on a longer screw and by god we will continue the tradition!!"  etc.   ;D  ;D

I could argue, the method I suggested would provide a physical mechanism whereby the bolt and threaded hole are locked together. The mushroomed bolt only provides (potentially) increased tension on the joint. It doesn't directly impede the rotation of the screw.

The mushroomed bolt will absolutely keep it from backing completely out. It can however (as Tiger learned) eventually allow the fastener to move. Even slight loss of torque on 2/3 of the fasteners could allow for clutch movement.  Any movement is the first stage of fatigue. Tigers clutch failed (fracture) from fatigue.  Even if it doesn't crack, loosened screws allow the clutch to rattle around and egg its holes and eventually the threaded holes in the rotor can be damaged as well. Ignore the rattling long enough and the screws fail then the fun really begins!  :o  The key is to keep the screws from backing out even a little. I think proper staking is more effective in that regard than the mushroomed screw method.

Please don't come to my door armed with pitch forks and torches and cries of heresy.  :o  However, if you have a reasonable argument, I'd love to hear it.  :)  :)

[Rikugun]

Wow. Really? Nothing? There's been a bunch of views since my last post and not one person has an argument for or against staking? The silence is deafening!  :D

I know there are people here who are unafraid of a technical discussion.....so if I don't hear a response soon I guess I'll just have to assume everyone is in complete agreement with me. Yup, 100% agreement. Who'da thought the status quo could be toppled so easily!??  :)  ;)

[lexx790]

How about welding the end of the bolt  ???

[Rikugun]

Thanks for your comment lexx790!
I considered that and at first liked the idea.  My first fear was having to grind away the weld if future removal was needed. The thought of little shards of metal sticking to the magnet and not being able to remove them all was a bummer. But then I considered the same eventuality if the bolt were peened - having to grind if removal later was needed. As a side note to that, I asked Tiger if he ground the peened bolt ends to facilitate removal and he said no. I would have been fearfull of damaging the rotor threads but he apparently had no issue with that. I wonder if drilling a welded (or staked, or peened for that matter) bolt end would make for easier containment of waste?

Another weld related concern was if the magnets would be affected by the welding process - either by heat or electrical fields. I'm guessing the heat would be minimal but the other I have no idea. Anyone?

[Lucky]

I don't weld, so i won't comment on that.

couple of things...  mushrooming the end of the bolt is pretty hard to do  1) your using graded bolts (you should be) and 2)fighting the force of the magnets.

Cutting an X or single slot in the end of the bolt seems to have done the trick for most everyone who has tried it.  this post from Tiger is the only one in recent memory where a starter clutch repair has failed.  I'm guessing the Mistress was one of the first he did & his technique has improved over time too...

Cutting a X or slot is simple & effective enough to do the job, plus has the advantage of being reversable, and your not mercilessly pounding on magnets, machined rollers & high stress parts to mushroom over the ends.  a couple of hits per bolt should spread the end.

-My take on life, lol

[Rikugun]

Lucky, I appreciate you comments. Some have expressed concern over the force required to peen the screw ends so the "slot" or "x" tip seems like a great (maybe necessary?) idea.

We'll never know why the 2 screws lost torque and the clutch fractured but I was surprised no one questioned it. Maybe everyone thought it a fluke and not mention worthy? Maybe the clutch had a hairline crack that went unnoticed during assembly. Subsequent fracture and vibration worked the screws loose? Who knows...

I initiated a PM with Tiger and he admitted being a "wee bit surprised" too. Interestingly, I just went back over that correspondence and missed this the first read:
"I was able, with some force, to get the three screws out without using my dremel tool...as I have done before on a couple of my rebuilds."    Tiger, is that to say you've  removed clutches with peened bolts before? If so, were loose screws or cracked clutches found?      

Anywho, back to the staking vs. peening....   I've had a few discussions with an engineer about the clutch fracture problems and securing the screws. Relative to the screws, this is an excerpt from an email he sent today:

"It's funny, I did a little reading on this the other day to reinforce what we were discussing.  The nuts and bolts (hardy har) of the issue was that when joining two threaded parts whose relative rotational position was critical, staking provided a superior mechanical connection that served to lock the parts,  while peening still only relies on friction under fastener head (and possibly under peened area if done effectively) to retain relative rotational position.  Of course, as you noted, the peening will keep the screw from falling out, but I think you've demonstrated that this isn't necessarily enough."

With respect to full disclosure, the engineer is one of my brothers, but he is not in the habit of telling me what he thinks I want to hear!  :)  Now while I don't expect everyone to abruptly abandon peening, I feel staking is an excellent option of securing the screws and, an easier process as well. Yes, many have peened the screws with, so far as we can tell, very low failure rate. But just because Yamaha failed to perform the staking effectually, I'm not going to summarily dismiss it as a viable option.   :)  ;)

just my 2 cents and YMMV, no warranties expressed or implied  :laugh:

[Tiger]

I initiated a PM with Tiger and he admitted being a "wee bit surprised" too. Interestingly, I just went back over that correspondence and missed this the first read:
"I was able, with some force, to get the three screws out without using my dremel tool...as I have done before on a couple of my rebuilds."    Tiger, is that to say you've  removed clutches with peened bolts before? If so, were loose screws or cracked clutches found?      

:) I did have to use a dremel on one early Vision flywheel to help remove one of the starter clutch screws...and the clutch was o.k...I seem to remember :P

Mine was done a while back and part of the problem was the red loctite broke down. This was probably due to not cleaning the threads on the screws/flywheel properly with something like brake and parts cleaner...I'm getting better at this (and other things Vision!!) with each rebuild ;)

8).......TIGER....... 8)

[Rikugun]

Thanks for the feedback Tiger.

Speaking of the loctite "breaking down"...   According to their web page, the red has a 24 month unopened shelf life, from date of manufacture!

The PDF technical sheet provides a key to decipher the alpha numeric manufacturing date code (on the bottle or packaging?).  Maybe it's just a ruse to promote sales, but I think I'll get a fresh tube to do my clutch bolts!  :)

[Lucky]

Couple of thoughts:
Q: how do you loosen a tight bolt or screw?
A: Impact

if your fully peening the end of the bolt your doing the same thing.  taking the strech out of the threads, as it were..

I've never considered locktite adaquet for critical applications even the green military stuff.  it is afterall, plastic. it's designed to take up space.  heat, harsh chemicals and age can deteriorate it.  it's fine to use, can't hurt, but my 2 cents: not up to the task of this application...

[Cdnlouie]

Working for Yamaha back in the 80's I did one Vision staking on the starter clutch.  This method takes a bit of proper technique which not everyone would have been proficient. I believe the reason they used this option was because it was the quickest warranty fix they could do since you did not need to remove the flywheel, etc.  Just pull the cover and peen the bolts and say good night!  It was a bit of insurance for Yamaha and it may have actually achieved their purpose. Mine lasted up until this year and 50k when I decided it was time to take a look. Sure enough they were floating, not moving yet, but only hand tight. I would be willing to speculate that this movement over time is most likely due to stretch on the actual threads, rather than movement of the bolt rotationally, because the bolts had not moved from the peen, but now they were loose.  This begs the question for why are the bolts loose since they really didn't move? The movement may well be in flywheel threads which are probably softer than the hardened bolt, but you can be sure that there is some stretch taking place here. The threads are actually being pulled out.

So the moral of the story may well be that the peen actually stopped the bolts from moving but did nothing to stop the bolts from stretching, thus we develop slackness over time, and then the process really gets going. Peening, notching probably doesn't make much difference in the long run.

And of course all this depends on how much each bike uses its' starter so it becomes very difficult to predict a length of time before they need to be checked for every owner.  All I can say is that I got 50000 km and they were due.  Tiger probably got about 30,000 plus km (maybe more) since he did his a few years back, but they were probably due to be replaced again. There have not been too many Visions with real long term data for this issue until now, so we might hear a bit more of this in the future from the long term riders.

When you go to sleep at night keep one eye on the stator and one eye on the starter clutch  ;D

Cheers fellows  ;)

[Rikugun]

Thanks Cecil, I'm glad you brought up this issue. Very insightful response. There is a lot of info here some of which I'd like clarification on..

First are the terms "staked" &. "peened". It seems you used the 2 interchangeably yet make a distinction between the two?  My intent is not to argue semantics but ensure I'm on the same page for clarity of discussion. My use of "staked" involves a punched deformation at the interface of the bolts edge and threaded hole such as to deny rotation.  The process of mushrooming the end of a longer screw I called "peened". Since the factory screw doesn't protrude beyond the plane of the rotor's interior, I'm assuming you did what I call staking to your bike. Please correct me if I'm mistaken.

I've learned (from this site) that the screws were staked at the factory, albeit ineffectually, but you're saying it was done under warranty? Not that it matters to this discussion but interesting nonetheless. Again, for clarification purposes, this is different from what QBS reports having been done to his V in '84 and subsequently adopted by ROV i.e. peening longer screws?

I had discussions regarding the concept of clamping force being lost across the assembly without the bolts actually backing out.  Stretch of the fasteners  (in this case the screws and rotor threads) were quickly dismissed. Stretching is implied in a torqued fastener so I assume you infer the stretching is beyond the elastic and into the plastic zone.  Since there is no additional axial load on the assembly we assumed that wasn't it. If that were the case, I doubt it would take so long to manifest.  Without some calculations that are beyond me, I can't say for sure. If you're right, I'd agree the more likely culprit is the rotor. We discussed one other theory that seemed more likely but moved on as we had not even anecdotal evidence that either scenario was occurring (that is until your post!). We settled on the screws backing out despite being peened and thought staking might be the answer.

To take from the equation the possibility of screws backing out, I prefer staking to peening. Based on your one example, there may be more to it. If the assembly can loosen, despite the screws retaining their relative position (from stretching or some other factor), that's a new wrinkle for sure. Whatever the culprit, this does not appear to be a "fix it and forget it type of repair". As you said, depending on usage and miles, there may be others out there needing to have a peek behind the rotor!

BTW, what was your reason for looking at yours, were you having symptoms? Was there any damage - worn mounting holes, shiny screws from slop, etc.

[Lucky]

My use of "staked" involves a punched deformation at the interface of the bolts edge and threaded hole such as to deny rotation.  The process of mushrooming the end of a longer screw I called "peened".

I believe slotting the end & spreading them with a punch is a happy medium.  (call it "Steak & Mushrooms" )  ;D

If the assembly can loosen, despite the screws retaining their relative position (from stretching or some other factor), that's a new wrinkle for sure.

Old School solution: split lock washer.  that's what they're for...

[Rikugun]

Quote
If the assembly can loosen, despite the screws retaining their relative position (from stretching or some other factor), that's a new wrinkle for sure.

If I'm understanding Cdnlouie's comments correctly,  he claims his screws had not backed out, the slop was attributed to some other mechanism.  In his case no form of safetying would have helped. While lockwashers are an accepted method to safety a fastener, it is not particularly aggressive. Where peening, staking and loctite have failed, a lockwasher will be of little consequence. Adding it to the mix couldn't hurt though.  :)

I think it boils down to inadequate design - not an uncommon thing. Take Cdnlouie's suggestion of rotor thread stretch. Stretch is figured into the equation but what if they calculated incorrectly? What if 6mm thread engagement in that material is insufficient to cope with the tension afforded by the installation torque?

What if the threads aren't stretching. How else could the clutch become loose? Consider the fit of the screws in the mounting holes - it is quite sloppy. No shouldered bolt in a snug hole here. What if they miscalculated the torque realized by the clutch during hard starting or a backfire? Then no amount of clamping force generated by those three screws can keep the clutch from shifting - even slightly. When any movement has occurred, it doesn't stop. It continues to move and begins wearing the associated parts until more movement is allowed and so on towards the inevitable conclusion. Or, until you recognize the symptoms and have a look see.  :o

Think about it. That clutch is expected to spin that engine over through friction provided by clamping force alone. Held to the rotor by 3 loose fitting screws. Think about the dismal amount of contact by the cap head screw's shoulder in a sloppy hole - and the forces exerted on that small area.  No key, no locating pins, no splines to help out. Just friction. Yikes!

I'm sure there are other possibilities and I don't pretend to know what's really going on, but it's fun to theorize! What I do know, is fixing it once is no guarantee you won't be in there again.    :)  :laugh:

[Cdnlouie]

What I'd like to know Rikugun is how you get so many words on one post? I just end up running into the drink at the bottom of the page and I'm done!

Why was I crawling around inside my stator case  ???  Actually I was addressing my oil leak from my stator grommets and decided it was time to check my starter clutch. In previous stator changes (number 3 now) I would always inspect the thread ends for movement and they were real good until 50k.

The Yamaha update was just a center punch to the edge of the bolt where it mated to the flywheel. Someone may have mentioned in times past that the Venture Royale uses the same starter clutch??? I have never checked the part numbers (there's a job for you), but they don't seem to have the same prevalent issue. We may never know some of the great mysteries of the universe.  The more you figure out the more you realize what you don't know  :-\.

[QBS]

Perhaps the closeness/smoothness of the Ventures V4 power strokes vs. the Visions V2 power strokes helps mitigate the shock to the crankshaft and all that is hung on it.  This would be especially and most prevalent at idle rpm.

[Rikugun]

What I'd like to know Rikugun is how you get so many words on one post?

It's a gift.  ;)  Or a curse, depending on your perspective. To those having to endure listening to me drone on and on over this or that I'd guess curse.   :o   :laugh:

Thanks for the followup. I wondered what had you poking around in there. My screw ends were punched as you described but did nothing as they came out with no resistance once broken free. I made sure to make it obvious for future viewing of the screw ends to determine if they've moved. This apparently does not guarantee that they are still providing adequate clamping force. Much truth to the axiom of the more you know etc. but it still makes for a lively technical discussion and invariably leads to a better understanding of the problem. Even if it can't be fixed permanently, I now know it, and will be aware of any warning signs.   

I've heard the Venture reference before (jasonm maybe?) and I'll get right on matching up those part numbers!  ;)  Or maybe give that a rest for a while...
QBS, you may have something there. It seems like a reasonable theory worthy of investigation but I'll leave that one to you!   :)  :laugh:

[QBS]

Rikugan's 3/6/2011 post on page one of this thread contains a picture of what the factory staking looks like.  A real sorry process!