Zenith El Primero Rainbow Flyback Upgrades (case back, strap)

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I undertook a small project today - installing a sapphire case back from Custom Watch Concepts (http://www.customwatchconcepts.com/) on my El Primero Rainbow Flyback. My watchmaker said I shouldn't put aftermarket parts on a watch with such an iconic special hi-beat caliber. I said I want to precisely _because_ it has that caliber and I want to see it! It's a high quality part, and I don' think I have anything to worry about. I'm also trying it on a strap for variety, even though I love the bracelet it came on. I got the Hirsch Kansas Buffalo Embossed Calf-Leather (https://www.hirschstraps.com/collec...-leather-watch-strap-in-black-with-red-stitch) because it's the closest thing I could find to the strap that came with these originally.
I love the result... the case back at least... I'll probably tire of the strap in a week and go back to the bracelet.
 
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Me likey! Seeing the movement of a great watch is half the appeal for me personally!
 
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I normally hate display backs, but I have to admit, it's kinda cool and the movement is stunning. Also one of the top 5 watches in my wish list- so I'm biased.
I would be cautious around water though as unless you have it pressure tested with that back, you don't know how solid that seal it.
 
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Me likey! Seeing the movement of a great watch is half the appeal for me personally!
Agreed! I think they would have done it back in the 90s if such parts had been developed. It's a joy to see the EP in action
 
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I normally hate display backs, but I have to admit, it's kinda cool and the movement is stunning. Also one of the top 5 watches in my wish list- so I'm biased.
I would be cautious around water though as unless you have it pressure tested with that back, you don't know how solid that seal it.

Good advice, thanks. I don't get this one wet because the service history is unknown. I
 
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Stunning watch - I have an early 90's 2-tone blue dial Rainbow but if I had it to do over again, I would have waited and bought the Flyback like yours. I also have a 1970's 3019 Surf, so I'm reluctant to even try to sell the merits of a 3rd EP to my wife. I am not big on display backs either and the Rainbow Flyback has a specially designed caseback that is unique to that model, so whatever you do - DO NOT LOSE IT! It is worth much more than the sapphire mod.

If you are going to wear this watch, I advise you to have it serviced. The EPs are lovely watches but unlike lots of other movements, they have parts that are quite prone to wear when they are not maintained. It is not uncommon for Zenith to change the entire mainplate when servicing an old EP as there are posts that hold gears used to set the time that are part of the plate. I learned this from my watchmaker when he serviced one of mine. He was Rolex trained on the Daytona and knows the specific parts that are sensitive to wear when the oils dry up.
 
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I have a question about the bracelet as I was going to put a leather strap on mine. How tight were the pins as they seem to be friction fit and not spring bar design? I have a bracelet block and punches. Is that how you removed them? Are they one-way (Tapered) or will they go in and out from either side.
 
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I have a question about the bracelet as I was going to put a leather strap on mine. How tight were the pins as they seem to be friction fit and not spring bar design? I have a bracelet block and punches. Is that how you removed them? Are they one-way (Tapered) or will they go in and out from either side.

I used a bracelet block and pin driver and a little hammer. You can push either way. It's easy.
 
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Stunning watch - I have an early 90's 2-tone blue dial Rainbow but if I had it to do over again, I would have waited and bought the Flyback like yours. I also have a 1970's 3019 Surf, so I'm reluctant to even try to sell the merits of a 3rd EP to my wife. I am not big on display backs either and the Rainbow Flyback has a specially designed caseback that is unique to that model, so whatever you do - DO NOT LOSE IT! It is worth much more than the sapphire mod.

If you are going to wear this watch, I advise you to have it serviced. The EPs are lovely watches but unlike lots of other movements, they have parts that are quite prone to wear when they are not maintained. It is not uncommon for Zenith to change the entire mainplate when servicing an old EP as there are posts that hold gears used to set the time that are part of the plate. I learned this from my watchmaker when he serviced one of mine. He was Rolex trained on the Daytona and knows the specific parts that are sensitive to wear when the oils dry up.

I won't lose the case back 😀

I might put it on a Speidel stretch bracelet and throw the original away though 😉
 
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Nice write up and makes me want to change out the strap for bracelet on mine. I also wondered if anyone can tell me hot to post on the for sale area if I am not yet approved or have many posts....thanks
 
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Nice write up and makes me want to change out the strap for bracelet on mine. I also wondered if anyone can tell me hot to post on the for sale area if I am not yet approved or have many posts....thanks
That's not allowed
 
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I just came across this thread and I have to say that your mod turned out lovely. I agree that the movement should be enjoyed! I have to wear my flyback on leather as I purchased mine secondhand with a bracelet that is too small for me 🙁 Anyone know where I could get (or would be willing to sell me) 2 spare links? I have had the piece for 6 months and haven't been able to enjoy it on bracelet...
 
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I just came across this thread and I have to say that your mod turned out lovely. I agree that the movement should be enjoyed! I have to wear my flyback on leather as I purchased mine secondhand with a bracelet that is too small for me 🙁 Anyone know where I could get (or would be willing to sell me) 2 spare links? I have had the piece for 6 months and haven't been able to enjoy it on bracelet...
Those can be found rather easily on eBay. Just perform a search there…
 
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Hi,
I know that the topic was created some time ago but could any of you measure the diameter of the thread of the caseback? Bradurani,
maybe you still have the original caseback at hand and you could measure it? thanx
 
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Nice mod! I have the same watch and always wish I could see the movement. Have you had any issues with the watch since you swapped the caseback out?
 
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Nice mod! I have the same watch and always wish I could see the movement. Have you had any issues with the watch since you swapped the caseback out?
No, but I don't swim with it. Actually I'm going to swap back though soon, keep it original
 
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I undertook a small project today - installing a sapphire case back from Custom Watch Concepts (http://www.customwatchconcepts.com/) on my El Primero Rainbow Flyback. My watchmaker said I shouldn't put aftermarket parts on a watch with such an iconic special hi-beat caliber. I said I want to precisely _because_ it has that caliber and I want to see it! It's a high quality part, and I don' think I have anything to worry about. I'm also trying it on a strap for variety, even though I love the bracelet it came on. I got the Hirsch Kansas Buffalo Embossed Calf-Leather (https://www.hirschstraps.com/collec...-leather-watch-strap-in-black-with-red-stitch) because it's the closest thing I could find to the strap that came with these originally.
I love the result... the case back at least... I'll probably tire of the strap in a week and go back to the bracelet.

Nice one!