Airone shift mechanism outer cover worn

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Jim Carey

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Apr 21, 2021, 8:05:49 PM4/21/21
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I have found the cause of the poor shift operation on my 48 Airone, the outer cover that contains the shift return spring has notches on each side at 12 o'clock and 6 o'clock, as the shift mechanism cover rotates, the vertical edge of these notches will depress a pawl on one side / lock the pawl on the opposite and this is how the mechanism rotates the shift shaft. One of the vertical surfaces on this cover is very badly worn, this is why the tranmission will shift up but it is very hard to shift down. 72 years of being hammerd down will lead to this.

I have included pictures and description of this in my blog of the restoration that I am posting to the WildGuzzi web forum


I can only think of two options:

1 - replace the shift mechanism outer cover with a new piece or a very good used one (anyone have one for sale) or 
2 - weld up the worn steel edge and machine it back to spec. I am not sure a weld will be hard enough to take the action

any thoughts?

Alan Comfort

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Apr 21, 2021, 8:21:54 PM4/21/21
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Maybe the welded/machined repair will only last for 50 years. In my view, that beats chasing down used parts that probably have the same issues.
Alan in Roberts Creek

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Jim Carey

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Apr 21, 2021, 10:21:14 PM4/21/21
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Only 50 years? That ought to be good enough, will try some welding tomorrow unless someone has a NOS piece just kicking about..... well it can’t hurt to ask

From: guzzi-...@googlegroups.com <guzzi-...@googlegroups.com> on behalf of Alan Comfort <alan.c...@gmail.com>
Sent: Wednesday, April 21, 2021 6:21:42 PM
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Subject: Re: [guzzi-singles] Airone shift mechanism outer cover worn
 

Michael Blumberg

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Apr 21, 2021, 10:55:56 PM4/21/21
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Jim

I just checked out the photos of your Astorino and it looks fabulous!

I’m curious... where are you located in Canada?

I’m in Vancouver near Alan 

Michael

Sent from my iPhone

On Apr 21, 2021, at 7:21 PM, Jim Carey <Jca...@br2architecture.com> wrote:



Jim Carey

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Apr 21, 2021, 11:03:02 PM4/21/21
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I am in Edmonton, Alan introduced us a couple years ago at the spring swap meet in the lower mainland, good to hear from you. The Airone joins my 57 Cardellino and a bunch of other Italian bikes from the 70’s. If you ever get to Edmonton look me up, would love to shoot the breeze. 

From: guzzi-...@googlegroups.com <guzzi-...@googlegroups.com> on behalf of Michael Blumberg <mblu...@ci-technologies.com>
Sent: Wednesday, April 21, 2021 8:55:53 PM

Michael Blumberg

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Apr 21, 2021, 11:38:18 PM4/21/21
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Jim

I remember now!

I am overdue to get over your way and hopefully next year I will.  It’d be worth it to see your Astorino first hand!

Take care!

Michael

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On Apr 21, 2021, at 8:03 PM, Jim Carey <Jca...@br2architecture.com> wrote:



SED Sci

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Apr 21, 2021, 11:49:23 PM4/21/21
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The ratchet on my GTV had a very similar problem - the ratchet would seize in one direction.  IIRC the problem was the pawls were different lengths and the depth of the hole for the spring in one pawl was too shallow.  The spring would coil-bind holding the nose of the pawl against the inside of the "collar". (red arrow is pointing to the outside of the collar)  When the collar was forced over the end of the pawl, the pawl jammed in its slot preventing the slotted body from springing back.  My recollection is that the depth of the spring hole in the long pawl was too shallow so I just drilled it deeper.  I may have shortened the pawl too.  Works fine now.
IMG_8712Mod.jpg

Jim Carey

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Apr 21, 2021, 11:56:15 PM4/21/21
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Thanks Shawn, that’s interesting I will check the depth of the spring recess in each pawl

When I fitted just one pawl for the direction of shift I was working the mechanism worked ok but better in the up direction. Could be a combination of worn parts but the jagged edge of the slotted ring is definitely causing a bind. 

Lots of interesting wear on this bike. 

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Jim Carey

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Apr 22, 2021, 10:13:53 PM4/22/21
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I welded up the shift mechanism piece with a Mig, machined the surfaces in the lathe and hand filed the vertical edge, shifted up and down now, seems to have solved the problem.

SED Sci

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Apr 22, 2021, 10:33:31 PM4/22/21
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Great!

John Ray

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Apr 23, 2021, 10:41:45 AM4/23/21
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A modestly interesting item — if true.  As the owner of a ’57 Falcone Sport and several Velocettes, I have been told that this external shift mechanism was the one invented by Veloce Motors (manufacturers of Velocette motorcycles) in 1926, and licensed to Guzzi.  Veloce re-engineered the mechanism to fit inside the gearbox shell a few yers later, but Guzzi continued to employ the external mechanism for decades.

Can anyone verify this story?

John
Napa, CA

Phil Mac

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Apr 23, 2021, 11:33:27 AM4/23/21
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Certainly looks a bit like the change mechanism on the 250 and 500 Guzzi singles. https://hmvf.co.uk/topic/35943-velos/

Phil
Coventry, England

Andrew Nahum

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Apr 23, 2021, 11:54:12 AM4/23/21
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I believe you are right about the Velocette origins. My 3 speed Scotts had the same mechanism and George Silk told me it was bought or licenced from Velocette. 
Andrew 

On 23 Apr 2021, at 16:33, Phil Mac <philmac.c...@gmail.com> wrote:



Alan Comfort

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Apr 23, 2021, 2:09:16 PM4/23/21
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Can't verify the story, but it sounds plausible. Carlo was a smart guy and he could have thought of it on his own. So who knows?
I also have a shed full of old Velos and 'slicers. They each have their own merits, but the end results are very similar in terms of 
performance, handling, braking and build quality. Keep these old bangers alive and well!

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briana...@gmail.com

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Apr 27, 2021, 1:49:54 AM4/27/21
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The positive stop foot change was invented by Harold Willis who was the race shop director of Veloce. he also experimented with supercharging and is credited with inventing the duel seat. This is explained in Ivan Rhodes books "Technical Excellence Exemplified and Passion of a lifetime".

It would appear that Moto Guzzi and Veloce shared several interesting ideas. When Stanley woods joined Veloce as works rider he brought with him experience of the suspension and weight distribution of the Guzzi, and alloy rims. This improved the Veloce racing specials so much that they began to win races in the 1930s. It can also be argued that the split frame design of the Veloce Roarer and the LE that allows the top of the frame to be removed from the engine and transmission was influenced by the Moto Guzzi design. This of course appeared many years before the "Integrated Drive Train"  of the BMW K series.   

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