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Scud

ANSWERED Re-engineering the Shift Spring

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And maybe someone could make a forum search. I remember a lot of threads and pics and solutions, though no details (happy ignorant KR owner). Belfast did a lot of research I think. He rode a Scura btw ;)

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Belfast and Baldini... seem like fun guys, but not active here lately. Here's a pretty good discussion that started in 2004 and got resurrected in 2015. It's about the spring situation and the various size bosses. One poor guy broke 6 springs.

 

http://www.v11lemans.com/forums/index.php?showtopic=2584

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And maybe someone could make a forum search.

There has been plenty of forum searching going on. For years.  :oldgit: Many things have been tried and many have died..  :)

17 years later, we still don't have a definitive answer. The one thing we know is the Guzzi spring doesn't work. It's high time we collectively came up with a fix that gets rid of that (hope I don't have to fix that stupid spring on the road) feeling. After all, this is *the* knowledge base on the V11S. 

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...a fix that gets rid of that (hope I don't have to fix that stupid spring on the road) feeling.

 

 

I know I wrote earlier that my wish was a coil spring kit. But the above is my real wish.

 

I am gravitating toward the conclusion that the fundamental design is good as-is. There seems to be two quality control problems, both of which are bypassed by the "Japanese" coil spring modification: 1) oversized boss that binds the spring, and 2) weak original springs (and possibly even weaker replacements).

 

Solution to 1 is measure and replace or modify as needed.

Solution to 2 is where I'm focused now. I'm in e-mail dialog with the spring manufacturer. Asked what it would take to make 50 or 100 springs.

 

If we can figure it out a better spring and Chuck can stress-test it, maybe we can get MG Cycle to stock it (cuz I don't want to go into the spring business). I can send a preselector to Chuck to hook up to motor - and it can do tens of thousands of shifts.

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Sounds like a plan. I know Gordon and Rick pretty well.. I'm reasonably sure they'd buy in.

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Ahh, on second thought. Unless they've changed their minds, MGCycle won't ship overseas. I sent a good percentage of the "Lucky Phil Extenders" overseas. It's a PITA filling out all the customs declarations, and that's probably why they don't. 

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You probably wouldn't make that much overseas business. Here we have that through already. It's been the 'Gerd' Feder - Gerd being the only one in this universe being able to roll proper springs and highly prised for that. Until the first stories of broken Gerd's rolled in at least. Sic transit gloria mundi (or so). Best cure so far seems to be having a spare one under the seat they say.

 

BTW: the KR I fetched from Italy 2 years ago as replacement for my old Greeny had this "Japanese Mod" installed already. Needles to say that, of course, between a lot of other crappy made things on this bike, the cover was leaking at this point.

 

Edit: just reread the mentioned thread and it seems as if the 'under seat spare one' charm didn't work for you, Scud ;)

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 Needles to say that, of course, between a lot of other crappy made things on this bike, the cover was leaking at this point.

"If" there is room, an O ring on the pedestal would cure that leak. Probably, that isn't an issue if we decide to go this way. 

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Edit: just reread the mentioned thread and it seems as if the 'under seat spare one' charm didn't work for you, Scud ;)

 

I think the "charm" depends on which seat. The spare spring was under the Scura's seat when the LeMans' spring failed.

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I would also vote for a quality control issue. First spring broke at about 10,000 miles. Second spring broke at 30,000 miles.

At that time I bought the kit ...blah blah blah. No problems for the last 80,000 miles. On a similar note...my 73 V7 sport broke a spring

and only has 11,000 miles. 5-speeder. Definitely a contaminated piece of metal. Look like a broken tree branch....if you have ever broken a dying tree branch...part of it breaks and then tears length wise for a bit till you start peeling the bark ..almost like it was torn off not broken.

I think the design is ok....Luigi was not following the recipe

andy  

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 Needles to say that, of course, between a lot of other crappy made things on this bike, the cover was leaking at this point.

"If" there is room, an O ring on the pedestal would cure that leak. Probably, that isn't an issue if we decide to go this way. 

 

I think Chuck to do the post on the selector cover "right" you're going to need to spot face the cover around the hole so the post sits perpendicular. If you do that then the post can have a wide integral flange that can be sealed effectivley with some loctite or sealant on the flange face. Not that keen on the post bolting to the less than flat internal cover plate face.

 

Ciao

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 Needles to say that, of course, between a lot of other crappy made things on this bike, the cover was leaking at this point.

"If" there is room, an O ring on the pedestal would cure that leak. Probably, that isn't an issue if we decide to go this way. 

 

I think Chuck to do the post on the selector cover "right" you're going to need to spot face the cover around the hole so the post sits perpendicular. If you do that then the post can have a wide integral flange that can be sealed effectivley with some loctite or sealant on the flange face. Not that keen on the post bolting to the less than flat internal cover plate face.

 

Ciao

 

Spot facing would be ideal of course. That was why I mentioned an O ring groove in the pedestal. We're still too early in this "design meeting" to worry about that, yet.  :)

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Last night I made a "spring" out of the thickest solder I could find to test my U-hook idea. I figure that since the 90-degree bend is one of the two failure points, that a more gradual, U-bend would be an improvement.

 

IMG_7120.jpg

 

Good News - it looks like there is room for the spring wire to be a little thicker (but not as thick as the solder)

Bad News - the hook would probably interfere with the operation of the spring that returns the shift lever to the middle position.

 

IMG_7125.jpg

 

If you look carefully in the above picture, you can see where the two springs almost meet. This is with the lever in the downshifting position.

 

 

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Good going on this, guys. Very early on, I sent a complete set of springs to a member in CA to pursue a custom build, but it never came to anything.

 

(FWIW, the broken spring from my 2002 warranty replacement gearbox broke in the coil, the inside showing a hollow and porous interior with a hard outer shell.  Seeing that, I tend to agree with "bad springs", but not an entirely bad design.)

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...

 

IMG_7125.jpg

 

If you look carefully in the above picture, you can see where the two springs almost meet. This is with the lever in the downshifting position.

But that's not the end position, is it? In the end positions the bump resp. the step would have contact with the small excentric pin, the lock pin as you could call it.

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