Hey everyone. I figured since I’ve posted a few serviced Yukis for sale, some people might be interested to see what goes into a service and why Yuki suggests one. Sure, there are plenty of pictorials and videos of a gen 3135 being serviced – this isn’t so much a tutorial, but rather a walkthrough of what I do and why it's a good idea to get a service.
So here we go with the latest:
Performance as it shipped. You can see the amplitude (the amount the balance swings, measured in degrees) is pretty low, there is a slight beat error (it swings to one side slightly more than the other) and it’s unacceptably fast.
Now – you could certainly get one, throw it in a watch, regulate it and be on your way. I’m sure that most of them would perform just as well as any Asian clone you’d get from the rep factories – for years even. But as I said early, Yuki recommend the Y3135 be serviced because the factories are dirty. You might think “oh, they’re overblowing it” to cover themselves. What follows are some photos showing why they’re not kidding. (PS – This isn’t meant to “shame” them or call them out for inferior QC/craftsmanship. I LOVE this movement and they’ve worked with me to resolve any show-stopping issues I’ve uncovered. But some do come pretty dirty, so I wanted to show exactly what that looks like) <3 you Yukiwatch
Uh-oh… those look like water spots on the barrel…
Aaaand, surface rust under the barrel
Those are some grimy keyless works!
Now on to the cleaning. Everything gets stripped down including the spring from the barrel. Even the cap jewel for the balance comes off!
And here it is! Everything in a Yuki 3135. All the parts on the left go through the cleaning machine. The parts on the right are put through separately as they’re either too fragile (hairspring/balance, pallet fork, jewels) or not at all (painted wheels, springs, etc.)
Now everything gets packed nice and neatly into the cleaning baskets
I’d started out using an ultrasonic, but it just didn’t clean like my L&R Mastermatic and you still had to dry the parts somehow. This one machine does everything! The little basket hooks in, you swing it around, drop in cleaning jar and let it run for a few minutes. It automatically reverses direction every few seconds creating a nice agitation. Then you lift it out, spin off the excess liquid and drop it into rinse #1. There should be a 3[SUP]rd[/SUP] jar for rinse #2 but it broke during delivery and I haven’t gotten a replacement yet. No matter – I haven’t put enough movements through to need a second rinse yet anyway. After that you drop it in that tube on the left where a heater sits and spin it in there for a while drying the parts with hot air. It’s fantastic.
Nice clean parts:
$100 worth of tools JUST to put the barrel back together
And now some pictures of the movement going back together clean. I tried to get similar shots so you could see the difference. No more rust on the main plate:
Now that is some clean stuff!
Once cleaned it really shines!
All done!
Now comes the hard part - This is where a lot of time can be spent because the main difference between the Yuki and a real Calibre 3135 is the balance setup. A Rolex uses an unsprung balance setup meaning the length of the spring is fixed and the rate is adjusted using screws on the balance wheel itself. The Yuki uses a regulated setup meaning there is a lever to adjust the length of the spring and one to adjust the rate. ETA movement have nice tools to regulate/adjust the movement. The Yuki? Not so much...
Here is the movement put back together after cleaning: Much better amplitude but the beat error is still there and the rate is off:
Here are the pins that need to be adjusted. The red arrow shows the rate adjustment lever and the blue arrow shows how to adjust for beat error. The issue is that there are no special tools for this setup so I just use carbon fiber tweezers and do it by hand. If you can see it move, you've moved it WAY too much. If you can feel it move you've still moved it too much
That's about it! Once I get the timing dialed in, it's ready to be installed! As I said, the adjustment is tricky and very sensitive. It's likely that once installed it would need a bit of regulation again. Even movements from watch supply stores that I've bought have needed tweaking once in a case. Even so, the Yuki provides the most gen Rolex look and feel from a movement perspective. Hope this helps demonstrate why it's a good idea to have it serviced!