Scud

I've confirmed the boss size on mine. My experience opening transmissions is limited to the V11. Here's a link to parts diagram of a Griso transmission. Totally different. http://www.harpermoto.com/parts-by-motorcycle/2000-up-moto-guzzi-motorcycles/griso-v-ie-1100-2005-2008/gear-box-selector-en-griso-ie-1100.html

So... what about the 2004/2005 Ducati 1000 Supersport? I am contemplating a trade of my red LeMans for this bike: It's an air-cooled V-Twin that makes only about 85 HP. Styling and suspension obviously more race-oriented than the V11 LeMans. But it's one of the last air-cooled, dry-clutch Ducatis. Sort of the end of an era like the V11 is to Moto Guzzi. This bike would have been in showrooms at the same time as the very last V11s and I think priced similarly at the time. They can be had for about the same (or less) than an Ohlins-equipped V11.

Thanks Chuck - that's how my pre-emptive replacements looked too. It seems that one potential solution is to stay with the existing thickness, but manufacture it so it looks like that - slightly more than 1.5 coils. That would keep the downshift travel under the limit you calculated. If the current downshift travel is 38, and the maximum safe travel is 30.48, increasing the coil length by 12 degrees would cut the downshift travel to 26 degrees. The fatigued springs work perfectly, until they break. There are no symptoms or advance warning. Another is to use thinner wire and add a coil - but maybe we could add 7/8ths of a coil or something like that. My thinking is that if the thinner wire is weaker (and less likely to break) that it will also allow more travel. Using some more travel in the at-rest position would increase the tension - possibly close to what the current spring does, or at least what a fatigued spring does. I can measure that space tonight, but in effect we already have a measurement. It is exactly 3 times the thickness of the spring. The third wire (in pic above) goes in like a tight feeler gauge. And this is kind of fun. But it would not be any fun at all if this was not a spare tranny and I was anxious to get a bike back on the road.

I can fit another spring in there, but it is tight. It binds when I move the arm. The spring wire would have to be a lot thinner to allow 2.5 coils and still move freely. So the question is... how much pressure is needed and could a thinner spring do it? What did you think of my idea to extend the coil by 10 (or even 15) degrees? As a point of comparison, the good springs I have removed had fatigue beyond that point anyway and they were still working.

It's hard to get a good measurement with the spring installed, but I estimate that the spring is at 22 degrees at rest when installed. Springs on the towel approximate the installed position. It relaxes slightly on an upshift: This looks like the spring might need to travel 38 degrees for a downshift. So... I'm no engineer, but what if the 90-degree tab was a little further along the bend. The current active coil is 1.5 turns, or 540 degrees. If we put the 90 degree bend at 550, that gives us 1.53 active coils. But more importantly, it cuts 10 degrees off the installed position, which would bring the downshift travel within spec.

Post #85 in this Wild Guzzi conversation. http://wildguzzi.com/forum/index.php?topic=93144.60 Maybe somebody can copy the picture. The showbike paint is a pretty faithful reproduction of that one.

I dig the throwback coloring - just like I dig the red, white, and blue Africa Twin. My concern with any ADV bike is that I know I will try to jump logs and climb rocky single track. I want the big wheels. But this would seem to be a perfect all-road machine and probably suitable for mild technical terrain. A long tour with some 4WD road exploration... I could get down with that. Maybe put a winch on the front...

The spring has 1.5 active coils. A thinner spring might be part of the solution. And extra coil would take us to 2.5. I'll take a bunch of measurements tonight. I fit a much thicker wire (the one I made out of solder) - so maybe a thinner wire with an extra coil would fit? A thinner spring brings a concern about it being able to hold the arm in place. From what I can see, the arm does not require a lot of tension to be held in place. Braking will flop it forward and sometimes land it in the right position. That's how I was able to get a few shifts on the way home after my recent spring-break (it sounds like more fun if you call it Spring Break). But when I found 3rd I was close to home so then I left it in 3rd. I also noticed that when I pre-emptively replaced the spring on the Scura that the original was significantly weaker than the replacement, which broke shortly thereafter. I put the original, weaker spring back in and it's been fine since - but maybe that's because there's a spare under the seat.

Thanks Chuck. I can measure the rotation tonight. Let's see... when did I last use a protractor for anything? Do I have one? Can I find it?

Great idea! After all, we know Guzzis are all about lightness. So I see this is partly in jest... but the guy did mention "exotic materials." I said "I'm not that worried about cost, what would it take to make it out of some exotic material?" Then he said that the exotic materials only have benefits in much thicker springs than the one we need. In his opinion, piano wire is the best available material.

No need. I have a few.

Do you have a spring on hand that you could measure and use their online calculator? If not, I could post some measurements. I think that with your experience you might make a better decision than I would. I'm kind of limited to: "Here's a spring. Can you make me one just it, but better?"

Ok. Flat tracker.... back to the Guzzi... Sadly, it's on 17R and 19F wheels. 18R and 21F would say ADV to me - and that's not a cheap upgrade.

Is it my imagination, or could you tie-down, tow, or winch-out the bike with those red "handles" on the forks? The rear subframe (surround-frame) has lots of place to grab/lift, and attach things. And the bash-plate looks serious.

When I mentioned the possibility of using a thicker wire, he said that would reduce how far the spring could bend (and therefore would break easier). I just ASS-u-med thicker would be better, but maybe thinner would be more durable. He also said that a weak spot is created anytime a tool holds the wire and a bend is applied. That's why we are seeing breaks most frequently at 2 specific locations. But maybe just using the highest quality raw material (piano wire) will solve it. It's easy to imagine a strapped-for-cash Moto Guzzi production manager choosing to downgrade the spring material to save a Euro a unit. "Hey we can save €10,000 this year by using material X instead of piano wire..." While I am getting a free "Spring 101" class, he's pretty clear that he doesn't give advice or make recommendations... the company makes springs to specifications, not to applications. The customer does their own engineering.

I like this quite a bit. Eagerly awaiting further news and a proper dual-sport test - road and dirt. Suspension travel looks moderate, not long like a KTM adventure or Honda Africa Twin, but not short like a scrambler.

I've seen breaks in two positions - personally and in reviewing other threads. I think the most common is in the coil (as in my picture on the first page). Next is that the small straight piece breaks off at the 90-degree bend. That's what Czakky described and what I experienced very shortly after installing it on my Scura. The break on the coil was on my LeMans, which has the correct size boss for the coil to go around. Anyway, I just heard back from the spring place. They can make 50 springs at $6.00 and 100 @ $4.00 each. I just talked with the representative. He said they would make it from piano wire. Apparently, there is another, slightly cheaper material that is commonly used, but it is weaker than piano wire. I'm going to mail him a broken spring and a new one. He thinks he may be able to use a slightly thicker wire, but has to have the sample in hand before promising anything. I don't want to get over-optimistic, but I think I smell a solution.

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. There is some travel remaining to end position. It was hard to hold the levers in place and take the photo at the same time. The discovery here, at least for me, is that the little right-angle part of the spring cannot be larger - because it would interfere with another spring.

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. 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. 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 easily transferable to your next.

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

I don't think it changed the handling. But the engine seems to rock a bit less at idle.

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.

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

...and my BMW K75s has a clever auto-retract spring that's actuated by the clutch cable at the transmission. And the Husky sidestand flies up and hits you in the balls if you stand too close to the bike. That's a mistake you make only once. I get distracted when there are people around. I've "stalled" my Scura more than once by putting it into gear with the sidestand down - thank-you e-nanny.