Re-engineering the Shift Spring

[Bill Hagan]

 

wow... shit missed this thread by ohhhh 21 pages...

ill try and catch up soon, but in the mean time did we figger out why its only the last of the V11's that break springs???

seems ya beg about 30k to a spring im on my 3rd now... why not just use a spring from an early 6spd ???

 

No apparent reason, but the spring is supposedly the same in all models - at least the replacement spring is.  I'm gonna open up my low-mile Greenie, which I believe has the original spring - and will report findings. But that'll be after the new springs show up.

 

Go open 3 beers - I think you can get through 7 pages per beer. 

 

 

I actually did better than that tonight, tho I did weigh in back in November.

 

In Atlanta right now at Manuel's Tavern in Atlanta's Poncey-Highland area.

 

Spent last many minutes but only one beer catching up.  OTOH, might have had another, but off to the nursing home to sit with Mom a bit.  Not many opps for that left.

 

Chuck, you and your unindicted coconspiritors are amazing. 

 

Bill

[dangerous]

 

It sure would be fun to have a look at an early preselector and pawl spring.. I didn't realize they never broke.

 

 

1. 2004 (a spare tranny from a parted Nero Corsa that mysteriously arrived at my house one day) - this preselector was the same as the 2003, but added the "banana" reinforcement plate. I installed this one on the LeMans, which is off enjoying Arizona with her new owner.

 

yooooo... scud do tell more what happened to this nero?

[dangerous]

 

 

Go open 3 beers - I think you can get through 7 pages per beer. 

 

opps... just cracked a Barverian 8.6 probely be all over after a 2nd...

[Scud]

@dangerous - I only bought the tranny from e-bay. Seller said it was from a Nero Corsa. That's all I know.

[werks]

It sure would be fun to have a look at an early preselector and pawl spring.. I didn't realize they never broke.

Woulda been helpful, right Chuck?

 

I had a customer that became... in my opinion, ridiculously obsessed that his v11 cafe sport spring was *going to break* because of allllllllllllll the wrong assumptions and frankly... ignorant speculation and assumptions over the internet about the “certain failure” of these springs.

 

So, I ordered another “bad” spring...took the whole assembly apart, and approached it’s replacement like I would anything....I basically measured and polished and precision fit everything that was reasonable or relevant. I remember putting a hardened shim washer or two somewhere (this was nearly ten years ago so my memory is mot 100%). The thing worked even better than to start and ladt I checked he was up around 55-60k miles with zero issues there.

 

I also had a neighboring shop give me a broken spring out of another bike... and took the good extracted cafe sport spring and the other broken one to a shop that does heat treating work for me. They’re opinion after breaking one and looking at the striation in the metal is that the springs likely suffered from a form of embrittlement either thru less than ideal manufacturing (the formng and /or heat treating), incorrect specificaton and or poor assembly or assembly specifications / QC. They did a hardness test of the wire, and it was too hard for the application, typically speaking, as these are commonly used. One of several conclusions we came to is that, as a result, if it was over extending, it would also mal-positioning and interfere with other compinents, further compromising it thru a nick/ stress riser, etc. That, combined with inherent vibration within the application meant there were *potentially* a few points of compromise, premature fatigue or possible failure. Or..... not.

 

I am not telling you anything you guys probably do not already know.

 

However... I noticed there is a lot of bad assumptions being made by people who are not subject matter experts, or just like to make snarky comments about Guzzis etc. That is a real shame. This is not that big a deal. The other thing I have personally witnessed many many times with people (Guzzi or otherwise) that have repeated failures of a component.... (specifically these type of shift springs....or clutches, or.... whatever), is that that beat their shit out of their machines in some way.

 

Each time, I would go ride with the person having the repeat failures,.. and EVERY TIME.... I immediately understood why. One guy had broken five return springs on his BMW /5. He shifted like he was a drunken irish clog dancer... kicking the damn pedal up and down. It was ridiculous. Another guy kept burning out Sport 1100 clutches. Seven, In three years to be exact. This guy loved to go online and shit talk how bad a machines Guzzis were. He was a robotics engineer. He treated his Sport like he was drag racing... slipping and dropping the clutch excessively in every direction, like it was a japanese modern multiplate slipper clutch and hecwas racing some bastard form if dirt track moto gp. He had very unrealistic, misguided expectation of the Guzzis design. He was an educated man... but still blamed the marque, rather than himself.... of course.

 

Chuck.... what you have done here is terriffic. I can say with an acceptable degree of certainty that you have designed and now developed a part with far more application considerations and actual testing than the Guzzi engineers ever had done. That is not a slight to them, what-so-ever. It is all too likely tgat Guzzis supplier screwed up some specification... and these bikes *were* built at a time when the assembly controls were inconsistent,( to be grossly understated about it), due to multiple factors....company mis / disorganization, labor issues etc etc.

 

I just spent hours going thru every post... and enjoyed it immensely.

(I have to say... that coil spring modification is very unwise for multiple reasons.... but an interesting effort).

 

I have to do this kind of thing for Vincents pretty constantly.

It is a LOT of work that no one really is ever able to appriciate or even have a frame of reference for.

 

I have had 0.000 spring failures on my v11LeMans. Frankly, I don’t anticipate one either. BUT.... I dont need to have someone field test it to know that you’ve already made a better mousetrap. So...

 

Please count me in for a batch of them.

Even ones from your bench rather than whatever manufacturer does is fine for me.

Let me know how much per spring, and how to get you the money... and then I can determine the number. Maybe ten?

I am just so impressed that someone actually DID something logical to help put all this spring nonsense to a rest in some way, and help support those having problems... I just want to support that. Maybe someday I’ll actually need one.

 

Stephen Pate

stephenpatemoto@gmail.com

[footgoose]

 

It sure would be fun to have a look at an early preselector and pawl spring.. I didn't realize they never broke.

Woulda been helpful, right Chuck?

 

I had a customer that became... in my opinion, ridiculously obsessed that his v11 cafe sport spring was *going to break* because of allllllllllllll the wrong assumptions and frankly... ignorant speculation and assumptions over the internet about the “certain failure” of these springs.

 

So, I ordered another “bad” spring...took the whole assembly apart, and approached it’s replacement like I would anything....I basically measured and polished and precision fit everything that was reasonable or relevant. I remember putting a hardened shim washer or two somewhere (this was nearly ten years ago so my memory is mot 100%). The thing worked even better than to start and ladt I checked he was up around 55-60k miles with zero issues there.

 

I also had a neighboring shop give me a broken spring out of another bike... and took the good extracted cafe sport spring and the other broken one to a shop that does heat treating work for me. They’re opinion after breaking one and looking at the striation in the metal is that the springs likely suffered from a form of embrittlement either thru less than ideal manufacturing (the formng and /or heat treating), incorrect specificaton and or poor assembly or assembly specifications / QC. They did a hardness test of the wire, and it was too hard for the application, typically speaking, as these are commonly used. One of several conclusions we came to is that, as a result, if it was over extending, it would also mal-positioning and interfere with other compinents, further compromising it thru a nick/ stress riser, etc. That, combined with inherent vibration within the application meant there were *potentially* a few points of compromise, premature fatigue or possible failure. Or..... not.

 

I am not telling you anything you guys probably do not already know.

 

However... I noticed there is a lot of bad assumptions being made by people who are not subject matter experts, or just like to make snarky comments about Guzzis etc. That is a real shame. This is not that big a deal. The other thing I have personally witnessed many many times with people (Guzzi or otherwise) that have repeated failures of a component.... (specifically these type of shift springs....or clutches, or.... whatever), is that that beat their shit out of their machines in some way.

 

Each time, I would go ride with the person having the repeat failures,.. and EVERY TIME.... I immediately understood why. One guy had broken five return springs on his BMW /5. He shifted like he was a drunken irish clog dancer... kicking the damn pedal up and down. It was ridiculous. Another guy kept burning out Sport 1100 clutches. Seven, In three years to be exact. This guy loved to go online and shit talk how bad a machines Guzzis were. He was a robotics engineer. He treated his Sport like he was drag racing... slipping and dropping the clutch excessively in every direction, like it was a japanese modern multiplate slipper clutch and hecwas racing some bastard form if dirt track moto gp. He had very unrealistic, misguided expectation of the Guzzis design. He was an educated man... but still blamed the marque, rather than himself.... of course.

 

Chuck.... what you have done here is terriffic. I can say with an acceptable degree of certainty that you have designed and now developed a part with far more application considerations and actual testing than the Guzzi engineers ever had done. That is not a slight to them, what-so-ever. It is all too likely tgat Guzzis supplier screwed up some specification... and these bikes *were* built at a time when the assembly controls were inconsistent,( to be grossly understated about it), due to multiple factors....company mis / disorganization, labor issues etc etc.

 

I just spent hours going thru every post... and enjoyed it immensely.

(I have to say... that coil spring modification is very unwise for multiple reasons.... but an interesting effort).

 

I have to do this kind of thing for Vincents pretty constantly.

It is a LOT of work that no one really is ever able to appriciate or even have a frame of reference for.

 

I have had 0.000 spring failures on my v11LeMans. Frankly, I don’t anticipate one either. BUT.... I dont need to have someone field test it to know that you’ve already made a better mousetrap. So...

 

Please count me in for a batch of them.

Even ones from your bench rather than whatever manufacturer does is fine for me.

Let me know how much per spring, and how to get you the money... and then I can determine the number. Maybe ten?

I am just so impressed that someone actually DID something logical to help put all this spring nonsense to a rest in some way, and help support those having problems... I just want to support that. Maybe someday I’ll actually need one.

 

Stephen Pate

stephenpatemoto@gmail.com

 

 

"(I have to say... that coil spring modification is very unwise for multiple reasons.... but an interesting effort)."

 

"very unwise but interesting"? please enlighten me. It's in my bike, and the statement seems contradictory.

 

Regarding the "certain" failure assumptions, my take is in the context of a rider... wanting to avoid the most likely failure of something that will ruin my day. The same way you think about the spring, I used to think about the aluminum flywheel in my bike (Tenni) and others Mandello and Scura. "so a few of them blew up, doesn't mean mine will. those guys probably thrashed them anyway" Internet hype= paranoia. Right?

I finally decided that the evidence was enough, the rational made sense, and the worry of the probability was not worth it. I changed my clutch. Most others have too.

 

I had a spring break. It was mounted on a boss that was incorrectly made (too large) which would not allow the spring to operate as designed. It ruined my day. I had another V11 LM at the same time so I changed the spring in it preemptively. It had the larger boss too. I swapped it not because of all the assumptions, but because of my reality, and the fact that I don't gamble. Your rationale suggests I shouldn't have worried about that one?

 

That spring has ruined days for a lot of folks. Some things are just made wrong, and need to be changed.

[MartyNZ]

Steven, you make some interesting and helpful points, but you included some criticisms without much explanation. It may help those of us who wonder "is he talking about me?" to elaborate on some things.

You say: "... ignorant speculation and assumptions over the internet..." & "...a lot of bad assumptions being made by people who are not subject matter experts...".

Do those comments refer to this topic, this forum, or elsewhere? 

[Chuck]

 

 

Please count me in for a batch of them. 

Even ones from your bench rather than whatever manufacturer does is fine for me. 

Hi, Stephen.. it's been a while. 

I didn't make any extras except a couple for Scud and one for me. I made several of different thickness and preload. Once I came up with what I thought was best, I gave all the rest the flotation test per Dave Richardson. 

Regarding the coil spring. Footgoose has done it, of course, although early on he mentioned some difficulty shifting and thinks it "may" need a stronger spring. What it does do, however, is introduce some variables in tension during the fore and aft travel of the pawl. Lucky Phil alluded to that, and agreed the torsion spring seems to be the way to go. Not to mention..  it would be very difficult to design a kit that would work for everyone, no matter their skill level, to install. 

Certainly, the pawl spring breakage is real. I know Mark at MG Classics and Todd at Guzzi Tech pretty well, and they have changed a boat load of them. Scud is a V11S whisperer, and from memory broke 3 in different bikes at about 10000 miles.

 

 

Chuck.... what you have done here is terriffic. I can say with an acceptable degree of certainty that you have designed and now developed a part with far more application considerations and actual testing than the Guzzi engineers ever had done.

Thanks, Stephen. As far as I *know* Guzzi didn't have a reliability lab at that time. Dr. John mentioned putting a front wheel against the wall, dropping the clutch, and seeing what broke when he was working at the factory.  (Greg Fields V twins book)

I gave it my best shot. There will be a *lot* of crow to eat if they start breaking in service, too.. but I'm reasonably sure we have the answer.

[werks]

 

 

Please count me in for a batch of them. Even ones from your bench rather than whatever manufacturer does is fine for me.

Hi, Stephen.. it's been a while.

 

Hey Chuck! I miss seeing ya, Man!

 

I didn't make any extras except a couple for Scud and one for me. I made several of different thickness and preload. Once I came up with what I thought was best, I gave all the rest the flotation test per Dave Richardson.

 

I understand.

 

Regarding the coil spring. Footgoose has done it, of course, although early on he mentioned some difficulty shifting and thinks it "may" need a stronger spring. What it does do, however, is introduce some variables in tension during the fore and aft travel of the pawl. Lucky Phil alluded to that, and agreed the torsion spring seems to be the way to go. Not to mention.. it would be very difficult to design a kit that would work for everyone, no matter their skill level, to install.

 

Exactly my thoughts.

As I know you know... there are reasons that coil springs are not commonly used inside engines and transmissions, even in a dry shift quadrent setups.

 

Certainly, the pawl spring breakage is real. I know Mark at MG Classics and Todd at Guzzi Tech pretty well, and they have changed a boat load of them. Scud is a V11S whisperer, and from memory broke 3 in different bikes at about 10000 miles.

Oh... I know it is a real thing. However, like many things about Guzzis (and motorcycles), it is grossly exaggerated on ye ole internets.

Still... I acknowledge that on some machines it is an issue for whatever, various reasons... and I like and trust your development of the part.

 

Chuck.... what you have done here is terriffic. I can say with an acceptable degree of certainty that you have designed and now developed a part with far more application considerations and actual testing than the Guzzi engineers ever had done.

Thanks, Stephen. As far as I *know* Guzzi didn't have a reliability lab at that time. Dr. John mentioned putting a front wheel against the wall, dropping the clutch, and seeing what broke when he was working at the factory. (Greg Fields V twins book)

I gave it my best shot. There will be a *lot* of crow to eat if they start breaking in service, too.. but I'm reasonably sure we have the answer.

No. No way. No crow. You have done the work, no one else has, to the best of my knowledge...and anyone who critisises the effort is wrong to do so.

 

As for people asking if I was referring to them with my comments... I am talking about the internet in general... I don't follow posts here much. As for the coil spring... If it is working... good on ya... that’s what matters. I’m not going to go into an design or engineering lecture. I hope it works out.

[luhbo]

Well, I see the crows circling. Let one brake and they'll go down.

Over here we had the same. Guzzi too stupid to design even the most simple spring (talking about Gepetto the spring bender), then thanks to one of the forum Gods who stood up and roled his own suddenly nearly everyone had at least 5 wonder spare ones laying around. Then something strange happened. The wonder springs started braking, the Guzzi ones stopped to do so. Lots of crow so to say.

 

Nonetheless, with this double wound, thin wire spring you should be on the safe side.

[swooshdave]

Steven, you make some interesting and helpful points, but you included some criticisms without much explanation. It may help those of us who wonder "is he talking about me?" to elaborate on some things.

"... ignorant speculation and assumptions over the internet..." & "...a lot of bad assumptions being made by people who are not subject matter experts...".

Do those comments refer to this topic, this forum, or elsewhere? 

 

Anywhere someone is allowed to express their opinion. While we think of this as detrimental it's actually a key component of crowdsourcing. If you get enough people expressing their perspective you will generally come up with the best solution. But for that to happen you need a range of perspectives. Some negative, some neutral and some positive. Even the most ridiculous notion may have either have some merit or trigger some discussion that can lead to success. It's also a learning experience, no one ever learned by being 100% right all of the time. It's ok to fail, or to have a bad assumption. Too many people are afraid to speak up which is too bad because right or wrong the may contribute without knowing it.

[Chuck]

 

Steven, you make some interesting and helpful points, but you included some criticisms without much explanation. It may help those of us who wonder "is he talking about me?" to elaborate on some things.

"... ignorant speculation and assumptions over the internet..." & "...a lot of bad assumptions being made by people who are not subject matter experts...".

Do those comments refer to this topic, this forum, or elsewhere? 

 

Anywhere someone is allowed to express their opinion. While we think of this as detrimental it's actually a key component of crowdsourcing. If you get enough people expressing their perspective you will generally come up with the best solution. But for that to happen you need a range of perspectives. Some negative, some neutral and some positive. Even the most ridiculous notion may have either have some merit or trigger some discussion that can lead to success. It's also a learning experience, no one ever learned by being 100% right all of the time. It's ok to fail, or to have a bad assumption. Too many people are afraid to speak up which is too bad because right or wrong the may contribute without knowing it.

 

Absolutely. 

[Chuck]

 Luhbo said

Then something strange happened. The wonder springs started braking, the Guzzi ones stopped to do so. Lots of crow so to say.

 

I'd say the new Guzzi springs are capable of breaking. Here's the one I installed last summer. It has less than 5000 miles on it.

2018-01-15_12-58-03 by Charles Stottlemyer, on Flickr

It was well on it's way to breaking.

So, I installed the new home made unbreakable coil spring.  caw caw..

But first..

2018-01-15_12-58-25 by Charles Stottlemyer, on Flickr

the diameter is just a smidgen (technical term) over .599". 16mm=.630, 15mm=.5905. Manufacturing tolerances.. the reason I didn't go with the 2mm dia. wire that perfectly fit Scuds selector shaft. 

Looking back at the reliability lab report..

 

.071 dia. spring with 2.45 active coils. The spring calculator says this spring has 62.5 degrees safe travel. Total travel of this spring in service is 39+15= 54 degrees.

Max safe torque of this spring is 6.8 inch lbs.

At 54 degrees, this spring generates 5.88 inch lbs.

At 54 degrees it's inner diameter is .622"

I decided that would be fine, and put it together.

But..

2018-01-15_01-15-11 by Charles Stottlemyer, on Flickr

The bigger radius on this spring rides on the sharp edge of the stamping. It is *most likely ok* to do that, but I'd be remiss if I didn't tell you to take your high speed die grinder.. what?? you don't have one?  Ok, maybe your Dremel? No? Jeeeze. How about a file and dress a radius where it rides that matches the radius of the spring. It doesn't have to be perfect.. just do your best.. but striving for perfection is only good craftsmanship.

A picture is worth a thousand words again..

2018-01-15_01-26-33 by Charles Stottlemyer, on Flickr

This is a rubber bob. Diamond impregnated rubber. Ooooh....shiny. 

2018-01-15_01-33-48 by Charles Stottlemyer, on Flickr

Cleaned it up in the solvent tank and compressed air, reinstalled on the Mighty Scura, and am confident I won't have to do this job again. (caw caw) 

[Scud]

Very nice Chuck. Eager to hear your riding impressions and if you notice any difference. 

[docc]

I just had to lift (and play-on-words) a couple phrases from this *good conversation* . . .

 

". . . striving for perfection is only good craftsmanship . . .  "

 

*Crow // sourcing*  . . . . caw!