Rolex Explorer II question.

[Watchtower]

My name is Dan. I am new to this forum. I am 60 and have been working on watches and clocks since I was 15. I just recently bought a pre-owned Rolex Explorer II Polar 42mm (Cal 3187 movement). I love the watch but have a question in terms of regulation. On the Timegrapher, the watch seems a bit more "out of beat" than I would expect from a Rolex. The milliseconds reading is 1.1ms on average. I was under the assumption that it should ideally be .3 or less. Is this true? And, if so, can anyone tell me how to adjust this number? Do I have to tweak the hairspring collet? or is there a dual regulator on the balance bridge? (I've yet to open the case) Thanks...  

[Delgetti]

Hello, you will find all information in this thread:

 

 

[JohnR725]

I think it would be helpful if you opened up your watch.  Googling there's a fair amount of information on the movement out there including the first link which has a nice picture of the balance bridge. Notice it has what resembles the standard Rolex stud holder for putting the watch in beat. Then you really don't want to mess with the Parachrom hairspring collet unless you have a special tool and you know exactly what you're doing.

 

https://rubberb.com/blog/technical-changes-of-the-rolex-explorer-ii-42mm/

http://static.rolex.com/flipboard/the-parachrom-hairspring.html