Yuki 3135 time fluctuation

[henrymaire]

Hello!
I found a rolex rep.
It's a submariner with 3135 yuki movement.
It has signs of shock, scratches...and the date was not working.
So i opened it, managed to put the date wheel in place
I had a problem with the keyless after replacing the winding knob, so i had to dismantle some parts to have the keyless work again.
Managed to put everything back and now i'm checking the accuracy.
Using tg timer and fiddling with the 2 levers on the balanced wheel i managed to get sastisfying results (cf picture)
But the watch behaves very strangely.
I leave it in a quiet place,
Sometimes it stays on time for 12 hours (a night) and then when i check it some hours later it has lost 10 min... And without winding it again, i check Calibration and it's still acceptable...
What happened? I'm lost here...

Envoyé de mon Redmi 4X en utilisant Tapatalk

 

[ado213]

loose canon pinion ?

 

[RayBubble]

Some time ago, i found a similiar issue with my JF16610 with SH3135 movent.

The messurements at the timegrapher looks perfect without any issue.

Unfortunately it lose some minutes on one day, mostly around midnight... sometimes it doesn't.
Somedays it happens when the date flips (sometimes not)

Strange behaviour for me...

However,
my watchsmith told me that this could be of a "lose" canon pinion, like Ado pointed out.

With this i learned that the minute wheel & canon pinion are working friction based together (& sometimes the chinese seem to make them to lose).

Here i found i good report on this & how to solve it:

http://blog.watchdoctor.biz/2018/02/11/what-is-a-cannon-pinion/