[Shop-talk] How to open clearance on a hardened pin?

[old dirtbeard]

I had a '73 MG V7 Sport which had a different swing arm but a similar
arrangement.

I would think that if they came out easily, they should go back in
reasonably easily. If not, something is interfering with the refitment.

Perhaps:

   1. inspect the fitment for any scoring or swarth that could be
   interfering (I am certain that you already did this)
   2. Swap the left bearing for the right to see if there are
   dimensional differences.
   3. Swap the bearing side you insert first into the arm
   4. As mentioned, use a light abrasion like crocus cloth or scotch bright
   pads to polish up the surfaces of the bearing and the swingarm cylinders

I know that it is little help, but if they came out without hammering, they
should go back without hammering. Something has changed that is causing the
interference fitment now and you will need to determine what has
happened/changed during the R&R process.

best,

doug

On Sun, Mar 24, 2024 at 3:57 AM Al Fuller <alfuller194 at gmail.com> wrote:

> Well, ok then... BTW, are the bearings and races not in the diagram you
> referenced or am I missing something?
>
> ________________
> Best Regards,
> Al Fuller
>
> On Sat, Mar 23, 2024, 11:23 PM Jim Franklin <jamesf at groupwbench.org>
> wrote:
>
>> Good thought but I should have specified that I tried inserting the pin
>> directly into the bearing race and it exhibited the same issue.
>>
>> jim
>>
>> On Mar 23, 2024, at 10:14 PM, Al Fuller <alfuller194 at gmail.com> wrote:
>>
>> Jim, I don't know this part/assembly but it seems to me that the original
>> engineering would not have required hammering. Added to that one side goes
>> in well but not the other, I'm wondering if the bike might have a little
>> eccentricity in the fit-up? Is it possible that it was laid down at some
>> point in the past and has a little twist in the assembly?
>>
>> ________________
>> Best Regards,
>> Al Fuller
>>
>> On Sat, Mar 23, 2024, 10:17 PM Jim Franklin <jamesf at groupwbench.org>
>> wrote:
>>
>>> I'm assembling a Moto Guzzi swingarm which attaches to the back of the
>>> gearbox. The gearbox has 2 recesses in which live plain roller bearings.
>>> The swingarm has threaded holes through which locating pins screw. The tips
>>> of the pins are unthreaded and locate into the ID of of the roller
>>> bearings. Parts #12 here:
>>>
>>> https://harpermoto.com/collections/1980-1984-v-50-iii-500-swing-arm
>>>
>>> The pins are known for being stuck yet mine came out easily, probably
>>> because the inner race was able to rest against the swingarm while the pin
>>> was being pulled out. Assembly is another matter. The bearings don't bottom
>>> out in their recess so the inner race has nothing supporting it when I
>>> screw the pins into the swingarm, and one pin is not sliding into the inner
>>> race (the other pin fits into both races as it should). I don't want to
>>> hammer on it and dent the races. I've sanded it with some 400 grit but I'm
>>> pretty sure the pins are hardened and so I haven't made any progress.
>>>
>>> Any thoughts on how to get this pin to fit in the bearing? Freezing it
>>> is not a great option because of the time it takes to get things installed,
>>> plus I'll need to do clearance adjustments.
>>>
>>> thanks,
>>> jim
>>> _______________________________________________
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