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Miyota 8200 - The Ultimate Workhorse? (Part 1)

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  • Henry Krinkle
    replied
    How old is it? Does it run as long as the specs state? Do you know when it was last serviced? It may need a service. It may just be a bit slow to start. I have found that mechanical watches can be delightfully/annoyingly singular in their habits.

    Leave a comment:


  • tzetz
    replied
    This article is priceless. I already have 3 watches using 8203 and this tour was really interesting for me.
    Just a small question.
    I have a watch which runs very accurate +3-4 sec/day but when it runs out of power and stops it takes about 7-10 winds/turns/ of the crown before the second had starts moving. Is there a problem with the movement?
    My other two watches start almost immediately after the beginning of the maual crown winding.
    Thank you for your support and reply!

    Leave a comment:


  • Syncro16
    replied
    Thank you Jun ever so much for this post. It is most interesting !
    I love my Citizen NY0040 even more now that I have seen it inside and read your knowledgable tour of this movement.
    Yes your effort of writing this is timeless, it is now Aug 2016 and still a gem.
    Thanks.

    Leave a comment:


  • b-a-r-t
    replied
    Hi, excellent post!

    Question: can my 52-0110 Citizen diver's 8210a caliber be replaced by any brand new Miyota caliber? If so, which one is best?

    Kind regards,
    Bart

    Leave a comment:


  • JunMel
    replied
    Hi,

    I am also puzzled about the rattling noise inside the watch as you've stated. The Miyota 9015 is an upgraded version of the Caliber 6105 and not in the line of the Caliber 8200 which is 'famous' for its rotor bearing's roaring sound. The Caliber 6105 is a bi-directional winding automatic while the Miyota 9015 is uni-ddirectional. The designs, as I've said are very similar except for the winding direction.

    Unlike the 6105, the 9015 has a 3-screw rotor fastener which I believe is a more secure system than the 6105's. The reason for the upgrade is that the rotor of the 6105 tends to break loose and often causes malfunction. You will know it has come loose when the rattling sound comes in for sometime. IMO, this will never happen to the 9015 because of the revised fastening system. I suspect a mis-seated movement retainer screw/clip inside the case that holds the movement against the case. This screw or clip can restrain the rotor's swing or even binds it when it gets stuck under the rotor. No winding means stoppage. Have it checked.

    In case the winding is sufficient and the rotor is free of any obstruction, the slowing down in daily rate is due to the settling of the lubrication on the pivots and inside the mainspring barrel. This is normal to any watch that has come out recently from servicing or has sat for quite some time in the showcase and just been recently purchased. It takes a while for the balance wheel to acheive the required amplitude and only then it can be regulated to the correct daily rate. This is the reason why most service shops retain your watch in their possession for at least two weeks to complete the 'settling period', to let the lubricants migrate and be distributed evenly in the critical points then finally regulated before it is released so that slowing/gaining does not happen when the owner is already using it. It is like breaking-in a new automotive engine.

    Have the movement holder screw checked. Hope that helps

    Leave a comment:


  • dinkerson
    replied
    Question for Jun (or anyone else in the know)...

    You seem to have a great deal of knowledge of Miyota movements (great post btw). I recently acquired a Kemmner automatic that uses a Miyota 9015 movement. I love the watch, and the time-keeping is generally good compared to the published specs, but I'm noticing a couple of worrying issues:

    1. The watch makes a pronounced rattling noise when you tap the case or otherwise jolt it. It's very noticeable (can be heard at arm's length), and the case or crystal doesn't need to be tapped very hard to produce the sound. I'm aware it's considered a fairly noisy movement relative to others, but this sound is different to the whirring noise of the rotor when it spins. It's a definite rattling sound caused by tapping the case. I've seen others complain of similar issues on other threads, without a clear answer. Do you know the likely cause/fix?
    2. The watch started out keeping very accurate time (after 1 week the watch was +2 seconds overall). It would tend to lose 1-3 seconds on the wrist during the day, but then gain them back overnight in the face up position on the nightstand. More recently, the watch seems to be consistently losing 4-6 seconds per day. I'm not sure if (a) this could be related to the rattling; or (b) it could be the result of the movement having stopped and been restarted (I read somewhere that each time the movement stops through lack of wearing and needs to be restarted, it will keep different time). Any thoughts on this inconsistency of time keeping?

    Any help much appreciated. I'm wondering if I need to get it looked at or whether I can try something myself first.

    Thanks!

    Leave a comment:


  • TylerEOT
    replied
    Great stuff, Jun! I do like the Miyota in my Magrette. They avoided the problems with it, by leaving off the date, and the seconds hand entirely! It runs a tad fast, but it doesn't make much difference the way I wear it. The only annoyance is the winding sound is a kind of grinding rattle.
    I see a lot of companies now going with the new 9015, including Magrette. Keen to try it.

    Leave a comment:


  • rgatkinson
    replied
    Very interesting article indeed. I've just purchased a Citizen Automatic NH8250-53X from Japan (sold out locally) that uses the 8200 movement. I wasn't aware of its pedigree but I am now. Sounds like I've invested wisely :-)

    Leave a comment:


  • JunMel
    replied
    Thanks Kurt, citchu. Surprised to read an old thread!

    @citchu, there are several factors affecting the accuracy of any watch. In the worst scenario, worn-out parts due to neglect or depriving a seemingly well-running watch of a much needed COA. Note that COA should be periodically given to a watch for a preventive maintenance. In the case of your 8200A, someone might have thrown the regulator to "+" position which gives a fast rate. If you center the regulator between the + and - and acceptable timing is acheived, then it is done. But if you happen to observe an erratic rate, then your watch must be submitted for COA. A good timing machine can spot errors in real time and it is only here that you can confirm if the watch requires a much needed COA.

    DSCN4498.jpg

    If you are familiar with the service history of your watch, I advise you to have it serviced every 5 years at most, that is if it is an ISO rated water resistant dive watch. For most watches with only 30 meters to 50 meters rating COA must be conducted periodically every 2 to 3 years. In every COA, have the gaskets replaced to ensure water resistance.

    COA - Cleaning, Oiling, Adjusting.

    Leave a comment:


  • kurt48
    replied
    Thanks Jun, LOVE Citizen !

    Kurt

    Leave a comment:


  • citchu
    replied
    My compliments for the overall best article I've yet seen on any watch subject. You confirm my feelings about Citizen quality, especially after the last 3 Seikos I've had have stung me (2 kinetics & a 7T92).
    A question about the 8200A...I just lucked into my first one, probably a 70's model, hooded lug SS 3 hand w/ gold colored dial & plastic crystal. To my amazement, it still works and keeps halfway decent time, tho a bit fast. Upon opening, I find the adjustment tab set way over on "+". Would I be right in guessing that cautious readjustments back toward the "-" mark will bring better accuracy--or is a good cleaning the answer? Many thanks in advance.

    Leave a comment:


  • JunMel
    replied
    Thank you all guys. I am hoping these kind of threads will benefit everyone.

    @Tyler: That is not actually a rattle but the sound coming from the bumping action of the rotor turning the ratchet wheel in one direction leaving the other direction freewheeling. The force of the mainspring rebounds the rotor, hence the bumping sound. Note that the rotor turns on a full bearing and its very sensitive that only a slight movement sends the rotor to jerk. Miyota did not rectify this over the years since it poses no problem in the automatic mechanism's performance. You can only hear this when you hold the watch near your ear, otherwise you won't notice it.

    @Barometer Watch: Seiko's are worse on this that you can actually hear a grinding sound. To make matters worst, the bearing employed on a Seiko has only 5 to 6 steel balls that tend to wear over the years and the rotor would grind on the plate and the bridge.

    In my 40 years experience servicing watches, except for those destroyed by water entry, I haven't seen a worn out 8200 bearing in normal use. I remember replacing bearings on a Seiko 5206, a couple of 6309's and dozens now on 7XXX series, but never on 8200's.

    Except for those Seiko calibers with jeweled barrel arbors, most Seiko calibers tend to eat the bushings for the barrel arbor. Whenever you see brassing on the barrel wheel (worst scenario) suspect a heavily worn-out arbor bushing. If the watch is left alone in this situation the click wheel will eat on the bridge and the barrel binds on the bridge and the plate giving an erratic timing. Seiko 7S26/36 is the weakest caliber regarding this as it doesn't have a replaceable barrel arbor bushing. The workaround is to punch near the arbor hole to compensate for the wear. I say "hole" and no bushings on 7S26/36.

    This is what greets you when the barrel arbor bushing is already worn out. Good timing for me since it was only beginning and the barrel wheel hasn't brassed yet. Note the wear pointed by the red arrow. The bushing is worn-out on its side near the wear on the bridge. It is replaceable though, so no problem here.
    PICT2378.jpg

    There are plenty of replacement bushings. And since this Seiko 6139 (courtesy of Mr. Sparks) is priceless to me, I also replaced the third wheel bushing with a jewel. Now it runs perfectly. Red arrow points to worn-out bushings.
    Replacements.jpg

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  • TylerEOT
    replied
    Thanks, Jun...and a question...

    We have the Miyota 8215 in the Magrette Bronze watches. Any interesting variations on this?

    The rotor has a peculiar rattle to it.

    Leave a comment:


  • Chris
    replied
    Super writeup!

    Thanks Jun. Fascinating.

    Chris

    Leave a comment:


  • Barometer Watch
    replied
    Is the miyota movement better than the 7S26 movement?

    Leave a comment:

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