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Bulova 21J - Citizen/Miyota 82S0 movement Disassembly

sstakoff
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sstakoff WRT Addict

sstakoff

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Sequential disassembly of a 21J Citizen/Miyota 82S0 skeleton automatic movement. Pics only at this time...
I've never worked on one of these before. Seems pretty straightforward although there are a number of differences from a typical swiss automatic. Does anyone know of a service manual for this movement?

The watch is running very fast (+60min/day) with very low amplitude. Removing the balance and pallets I find that the train runs sloppy with minimal wind on the mainspring. Escape wheels runs, then stops and starts several times before the wind is fully released. Nothing obvious on disassembly, but I do see some excess oil has leaked below some of the jewels and is present on the flat side. Perhaps this has attracted some dust or similar. Going to give it a good cleaning and see if that solves the problem - I suspect it will.

More pics here:  https://adobe.ly/2LLB4Jj

DSC_0616-1.thumb.jpg.fcc297b9376389419ae26e2fc279b055.jpg

Edited by sstakoff
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sstakoff WRT Addict

sstakoff

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19 minutes ago, clockboy said:

Looking at your l pics the hairspring does not seem to be sitting correctly on the final bend. This could cause regulation issues.

Thank you - I do agree. Not certain this would create the extremely low amplitude observed. I think that is probably due to a lack of power coming through the train, which is consistent with the action observed with the escapement removed. But, perhaps the hairspring is more to blame. Just don't understand how this would occur suddenly - I assumed the spring was likely in this condition when the movement was manufactured.Will see how the train behaves after cleaning - I haven't had time to put it through the machine yet. I'm also writing this up as a walkthrough (see jdm comment above) - so will repost when that's done.

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    • Neverenoughwatches
      Commando special

      By Neverenoughwatches · Posted

      Looks that way, if it had any amount of significant jewel count it would say so on the dial. 
    • Neverenoughwatches
      Gamblin Gamsol for cleaning?

      By Neverenoughwatches · Posted

      Light naptha is what you need to be looking for. The carbon to hydrogen ratio is high with heavy naptha, it doesn't evaporate as well as light naptha and is prone to leaving more residue. Try tom's suggestion of the mirror test.
    • Neverenoughwatches
      I'm going to be setting up a decent little workshop here at home.

      By Neverenoughwatches · Posted

      Its a big item Michael and a lot that could go wrong with the process of getting it to its new location. I once helped install one of these units into a conservatory that i had built. It was big and bloody heavy and took six of us to get it in safely. If you have sliding doors and you need to remove the whole frame then that may or may not go well. But i would advise getting a professional in if you have little knowledge on the installation of them. The glazing of the doors could well be 6mm laminated glass which again will be heavy very heavy if the glazing units are big. The glass would also need to be set up and packed correctly to open the doors properly more so if they are unframed and the sliders are upvc. Seems a shame but if no one is biting and that may be due to having no warranty i guess the only takers might be someone that installs them for a living and knows how to repair. If its fibreglass just be careful, i sometimes have to cut fibreglass baths out and they are nasty to work with . Thick gloves are definitely recommended,  not fun picking out fibreglass spells two days later that have started to go septic. Good luck with it all matey.
    • tomh207
      Gamblin Gamsol for cleaning?

      By tomh207 · Posted

      I don’t know anything about this product, however assuming you have it if you put a drop on a mirror or piece of glass lying flat on a table and leave it to evaporate if it leaves any sort of residue it is not really suitable for watch part cleaning.   Tom
    • Michael1962
      I'm going to be setting up a decent little workshop here at home.

      By Michael1962 · Posted

      Well I put the spa on Gumtree (selling service) to try and sell it as it only needs a recirc pump to get it going. However, it weighs circa 250kg, so there's 4 fairly strong guys, and I would have to remove the sliding door in the room completely to be able to get it out, as well as clearing out a multitude of potted plants and the Alfresco outdoor setting to be able to get it out. Then move nearly everything in the back of the garage to be able to push it through to the front of the house. I would also need to hire furniture skates to be able to shift it around as carrying it is out of the question. Then someone would need a trailer to get it to their place as you won't get it on the back of a ute. So, the only answer is, out with the reciprocating saw and cut it all up into manageable pieces. Crying shame as it is in really good nick. I was only asking $1,500 and only got two bites, but it would only take something to go wrong with removing the sliding door etc that everything I make on the sale could go out the door on repairs etc. It would have been nice to be able to turn it into tools etc, but que sera sera. I don't know about the rest of the world, but there just seems to be very little interest from people wanting to buy things secondhand.  
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